Damper

Abstract

A damper for damping vibrations of a structure comprises: a first damping unit, comprising a first damping body having a first mass (m.sub.1), a first spring element having a first spring constant (k.sub.1) and a first damping element having a first damping constant (c.sub.1), wherein said first damping body is configured to be attached to said structure via said first spring element and said first damping element; and a second damping unit, comprising a second damping body having a second mass (m.sub.2), a second spring element having a second spring constant (k.sub.2) and a second damping element having a second damping constant (c.sub.2), wherein said second damping body is configured to be attached to said first damping body via said second spring element and said second damping element.

Claims

1. A damper for damping vibrations of a structure, comprising: a first damping unit, comprising a first damping body having a first mass (m.sub.1), a first spring element having a first spring constant (k.sub.1) and a first damping element having a first damping constant (c.sub.1), wherein said first damping body is configured to be attached to said structure via said first spring element and said first damping element; and a second damping unit, comprising a second damping body having a second mass (m.sub.2), a second spring element having a second spring constant (k.sub.2) and a second damping element having a second damping constant (c.sub.2); wherein said second damping body is configured to be attached to said first damping body via said second spring element and said second damping element; wherein m.sub.0 is the mass of said structure: $\mathrm{.Math.}=\left(m_1+m_2\right)/m_0;$ ${\omega }_0=\frac{\surd k_0}{m_0};$ ${\omega }_2=\frac{\surd k_2}{m_2};$ ${\Omega }_2={\omega }_2/{\omega }_0;$ wherein 0.018≤μ≤0.25; and wherein ≤.sub.2 is selected such that an estimate d*.sub.e of an ensemble radius of the damper defined by $d_e^{*}\left(\mu ,{\Omega }_2\right)=1-{\left(\frac{9}{2}\frac{{\mu \left(1+\mu \right)}^{5/2}{\Omega }_2^4}{{\left(1-{\Omega }_2^2\right)}^{3/2}\sqrt{3+6{\Omega }_2-\sqrt{1+{\Omega }_2^2-2{\Omega }_2^4}}}\right)}^{1/4}$  fulfills the relation d*.sub.e≥0.375.

2. (canceled)

3. A damper according to claim 1, wherein Ω.sub.2 is selected such that d*.sub.e>0.40.

4. A damper according to claim 3, wherein Ω.sub.2 is selected such that d*.sub.e>0.45.

5. A damper according to claim 1, wherein said first spring element and/or said second spring element comprise a coil spring.

6. A damper according to claim 5, wherein said first damping body and/or said second damping body is configured for a linear movement having a horizontal component and/or a vertical component, the damper preferably comprising at least one guide element for guiding said linear movement.

7. A damper according to claim 1, further comprising a flexible element on which said first damping body and said second damping body are arranged.

8. A damper according to claim 7, wherein said flexible element comprises a beam, a bar, a rod and/or a leaf spring.

9. A damper according to claim 7, wherein said first damping body and/or said second damping body is movably arranged on said flexible element.

10. A damper according to claim 7, furthermore comprising a shear damping element attached to said flexible element and/or to said first damping body and/or to said second damping body.

11. A damper according to claim 10, wherein said shear damping element is configured to dissipate vibration energy through friction and/or magnetic forces.

12. A damper according to claim 1, further comprising a pendulum configured to be suspended from said structure.

13. A damper according to claim 12, furthermore comprising a liquid tank attached to said pendulum.

14. A damper according to claim 13, furthermore comprising obstacles submerged within said liquid tank.

15. A damper according to claim 1, wherein said second damping element comprises a dashpot, comprising: a cylinder which is at least partly filled with a viscous liquid, said cylinder being attached to one of said first damping body and said second damping body; a piston having a piston body which is submerged in said viscous liquid and a piston rod connected to said piston body, said piston rod being attached to the other of said first damping body (3) and said second damping body, wherein an outer diameter of said piston body is smaller than an inner diameter of said cylinder; and a piston ring having an outer diameter larger than said outer diameter of said piston body and smaller than said inner diameter of said cylinder, wherein said piston ring is mounted to said piston body such as to be movable in a plane perpendicular to said piston rod.

16. A damper according to claim 15, wherein said piston body comprises a piston body main part and a piston body cover part attached to or integral with said piston body main part such as to slidably hold said piston ring.

17. A damper according to claim 1, wherein said first damping body and/or said second damping body comprises two or more plates attached to each other, e.g. being bolted together.

18. A structure, comprising a damper according to claim 1.

19. A structure according to the claim 18, wherein the structure is a wind turbine tower, a building, a building floor, a bridge, a footbridge or stairs.

20. A computer-implemented method for configuring a damper according to claim 1 for broadband damping action, comprising: defining an ensemble of different structures whose vibrations are to be damped; computing, for each structure out of a set of structures distributed throughout said ensemble, a maximum frequency response H.sub.∞ as a function of vibration frequency; minimizing a highest value of said maximum frequency response H.sub.∞.

Description

LIST OF FIGURES

[0021] FIG. 1 is a sketch of a one-DOF structure with mass m.sub.0. The elastic stiffness is given by k.sub.0, and the linear damping is given by c.sub.0. We look for the motion of m.sub.0 due to and external influence f.

[0022] FIG. 2 is a sketch of a structure of mass m.sub.0 with an attached Traditional Damper, also known as a Tuned Mass Damper (TMD). The Traditional Damper consists of m.sub.1, k.sub.1 and c.sub.1, which are tuned to minimize the motion of m.sub.0 due to an external influence f.

[0023] FIG. 3 is a sketch of a structure of mass m.sub.0 with an attached Series Damper. The TG Broadband Damper according to the invention can be schematically represented in this way. The Series Damper comprises m.sub.1, m.sub.2, k.sub.1, k.sub.2, c.sub.1 and c.sub.2, which are tuned to minimize the motion of m.sub.0 due to an external influence f.

[0024] FIG. 4 illustrates the frequency response of a simple structure (with one DOF) with undamped eigenfrequency f.sub.0=1. Such a structure is shown in FIG. 1. The forcing frequency f.sub.F is shown on the abscissa. The blue curve shows a system with low damping, and the red curve shows a system with a higher damping. In each case, a dashed curve shows the peak response as expressed by Eq. (1).

[0025] FIG. 5 illustrates an example of a typical frequency response of a tower with multiple DOFs. The mode frequencies appear as peaks in the frequency response plot. Above the first three 3 mode frequencies f.sub.1, f.sub.2 and f.sub.3, the corresponding mode shapes are sketched above the corresponding frequency. When the structure is forced at the frequency f.sub.1, it will respond by bending into the shape sketched above f.sub.1. Similarly for forcing at f.sub.2 and f.sub.3. Successively higher mode frequencies correspond to modes with successively more complicated mode shapes.

[0026] FIG. 6 illustrates the frequency response of a composite structure (this example has 2 DOFs). The solid curve shows the response amplitude. Compare this to the single-DOF frequency response curves shown in FIG. 4. The black dot shows the peak of the response, with the dashed curve indicating the peak value H.sub.∞=8.25, which can be interpreted by Eq. (2) to give ζ.sub.eq=0.061.

[0027] FIG. 7 is an illustration of Ensemble Tuning. The plane shows the structure parameters, i.e. the structure eigenfrequency f.sub.0 and the structure modal mass m.sub.0.

[0028] Left: The Ensembles used according to embodiments of the invention. The parameters are normalized by some nominal values f.sub.0,nominal and m.sub.0,nominal. The grey circular region named ε represents the Ensemble, i.e. the range of structures, for which a given TG Broadband Damper is tuned. The Ensemble Radius d.sub.e is the Radius of ε. The black square indicates the nominal structure. The red square shows a structure within the Ensemble, but with a lower frequency than the nominal structure. The blue square shows a structure outside the Ensemble, with a higher eigenfrequency and a lower mass than the nominal structure.

[0029] Right: Example of a more advanced Ensemble, which could be used with a damper according to the invention in the future. The Ensemble consists of two disjoint non-circular regions ε.sub.1 and ε.sub.2. The damping requirements could be different in the two regions, e.g. with a higher damping required in ε.sub.2 than in ε.sub.1. The green square indicates a structure within ε.sub.1, the black square indicates a structure within ε.sub.2, and the magenta square indicates a structure not within the Ensemble.

[0030] FIG. 8 shows a 1.sup.st schematic embodiment of the damper according to the invention.

[0031] FIG. 9 shows a 2.sup.nd schematic embodiment of the damper according to the invention.

[0032] FIG. 10 shows a 3.sup.rd schematic embodiment of the damper according to the invention.

[0033] FIG. 11 shows a 4.sup.th schematic embodiment of the damper according to the invention.

[0034] FIG. 12 shows a 5.sup.th schematic embodiment of the damper according to the invention.

[0035] FIG. 13 shows a 6.sup.th schematic embodiment of the damper according to the invention.

[0036] FIG. 14 shows a 7.sup.th schematic embodiment of the damper according to the invention.

[0037] FIG. 15 shows an 8.sup.th schematic embodiment of the damper according to the invention.

[0038] FIG. 16 shows a 9.sup.th schematic embodiment of the damper according to the invention.

[0039] FIG. 17 shows a 10.sup.th schematic embodiment of the damper according to the invention.

[0040] FIG. 18 shows a 11.sup.th schematic embodiment of the damper according to the invention.

[0041] FIG. 19 shows a 12.sup.th schematic embodiment of the damper according to the invention.

[0042] FIG. 20 shows a 13.sup.th schematic embodiment of the damper according to the invention.

[0043] FIG. 21 shows a 14.sup.th schematic embodiment of the damper according to the invention.

[0044] FIG. 22 shows a 15.sup.th schematic embodiment of the damper according to the invention.

[0045] FIG. 23 shows a 16.sup.th schematic embodiment of the damper according to the invention.

[0046] FIG. 24 shows a 17.sup.th schematic embodiment of the damper according to the invention.

[0047] FIG. 25 shows a 18.sup.th schematic embodiment of the damper according to the invention.

[0048] FIG. 26 shows a 19.sup.th schematic embodiment of the damper according to the invention.

[0049] FIG. 27 shows a 20.sup.th schematic embodiment of the damper according to the invention.

[0050] FIG. 28 shows a 21.sup.st schematic embodiment of the damper according to the invention.

[0051] FIG. 29 shows a 22.sup.nd schematic embodiment of the damper according to the invention.

[0052] FIG. 30 shows a 23.sup.rd schematic embodiment of the damper according to the invention.

[0053] FIG. 31 shows a 24.sup.th schematic embodiment of the damper according to the invention.

[0054] FIG. 32 shows a 25.sup.th schematic embodiment of the damper according to the invention.

[0055] FIG. 33 shows a 26.sup.th schematic embodiment of the damper according to the invention.

[0056] FIG. 34 shows a 27.sup.th schematic embodiment of the damper according to the invention.

[0057] FIG. 35 shows a 28.sup.th schematic embodiment of the damper according to the invention.

[0058] FIG. 36 shows a 29.sup.th schematic embodiment of the damper according to the invention.

[0059] FIG. 37 shows a 30.sup.th schematic embodiment of the damper according to the invention.

[0060] FIG. 38 shows a 31.sup.st schematic embodiment of the damper according to the invention.

[0061] FIG. 39 shows a 32.sup.nd schematic embodiment of the damper according to the invention.

[0062] FIG. 40 shows a 33.sup.rd schematic embodiment of the damper according to the invention.

[0063] FIG. 41 shows a 34.sup.th schematic embodiment of the damper according to the invention.

[0064] FIG. 42 shows a 35.sup.th schematic embodiment of the damper according to the invention.

[0065] FIG. 43 shows a 36.sup.th schematic embodiment of the damper according to the invention.

[0066] FIG. 44 shows a 37.sup.th schematic embodiment of the damper according to the invention.

[0067] FIG. 45 shows a 38.sup.th schematic embodiment of the damper according to the invention.

[0068] FIG. 46 shows a schematic cross-sectional view of a dashpot used as a part of the second damping element in an embodiment of the damper according to the invention.

2 TECHNICAL DEFINITION OF DAMPING

[0069] 2.1 Simple Damped Structure

[0070] A structure can be described in a simplified manner as shown on FIG. 1. The structure has one moving mass m.sub.0, so it is said to have one degree-of-freedom or one DOF.

[0071] In FIG. 1, a mass m.sub.0 is attached to the ground via a spring element (or simply “spring”) of spring constant or spring rate (or simply “rate”) k.sub.0 and a linear damping element of damping constant or damping rate (or simply “rate”) c.sub.0. The constants k.sub.0 and c.sub.0 are force coefficients, with the spring rate k.sub.0 measured in units of

[00001]$\frac{N}{m}$

and the damping rate c.sub.0 measured in units of

[00002]$\frac{N}{m/s}.$

When the structure displacement is x.sub.0 and the structure velocity is {dot over (x)}.sub.0, the force on the structure is F=−k.sub.0.Math.x.sub.0−c.sub.0.Math.{dot over (x)}.sub.0. The linear damping element can be visualized as the oil-filled piston-in-cylinder shock absorber (also known as a dashpot) used in an automobile.

[0072] It is practical to introduce the undamped eigenfrequency f.sub.0, with

[00003]$2\pi f_0=\sqrt{\frac{k_0}{m_0}},$

and the non-dimensional damping ratio

[00004]${\zeta }_0=\frac{c_0}{2\sqrt{k_0{m}_0}}.$

If the structure is pulled to the side and released, it will oscillate back and forth at a frequency close to f.sub.0. In the presence of damping, ζ.sub.0>0, these oscillations decay over time.

[0073] Consider now a horizontal force f=F.sub.0 cos(2πf.sub.Ft) applied to the structure. The forcing has amplitude F.sub.0 and varies at a frequency f.sub.F with the time t. After some time has passed, the structure will respond to the forcing by performing oscillations back and forth at the forcing frequency f.sub.F and at the amplitude x.sub.0.

[0074] A frequency response is the normalized amplitude

[00005]$H=\frac{x_0}{F_0/k_0}$

as a function of the forcing frequency f.sub.F. A frequency response plot for the damped structure on FIG. 1 is shown on FIG. 4.

[0075] It can be see that the response is very large when f.sub.F≈f.sub.0. This phenomenon is known as resonance. At resonance, the response H is only limited by the damping ratio ζ.sub.0. Indeed, the maximum value (mathematically speaking the infinity norm) of the response

[00006]$H_{\infty }=\underset{f_F}{\max }\left(H\right)$

is described to a good approximation by

[00007]$\begin{array}{cc}{H}_{\infty }\approx \frac{1}{2{\zeta }_0},\mathrm{or}{\zeta }_0\approx \frac{1}{2H_{\infty }}.& \left(1\right)\end{array}$

[0076] The approximation, Eq. (1), is indicated on FIG. 4 by the dashed horizontal lines showing the approximate maximal response values.

[0077] 2.2 Composite Structures

[0078] Real structures are composed of several parts, which can move independently, but are elastically connected. We say that they have more than one DOF. In this case, a periodic forcing will result in a more complicated frequency response than that of a single-DOF structure, typically with more than one resonance peak in the frequency response. Each resonance peak is associated with a mechanical mode and a particular mode shape, i.e. a particular shape of the vibrating structure. Each mode is also associated with a modal mass. A Vibration Damper is often installed with the purpose of damping the motion of a particular identified mode. An example of a frequency response of a multi-DOF tower with sketches of the associated first few mode shape is shown in FIG. 5.

[0079] In contrast to a single-DOF structure, a multi-DOF structure is not characterized by a single number expressing its damping. The mechanical behavior of a structure is however completely described in terms of its frequency response function H, so various measures of damping can be derived from H. FIG. 6 shows a frequency response for a multi-DOF structure. Of particular interest to structural engineers is the peak value H.sub.∞ of H, as indicated by the black dot on FIG. 6. At the forcing frequency where the peak occurs, the structure will respond strongly, possibly leading to problems as discussed in Sec. 1 above.

[0080] We shall however introduce an equivalent damping ratio ζ.sub.eq by the relation shown in Eq. (1).

[0081] We define

[00008]$\begin{array}{cc}{\zeta }_{eq}\approx \frac{1}{2H_{\infty }}.& \left(2\right)\end{array}$

[0082] The equivalent damping introduced in Eq. (2) will be used to characterize the damping supplied to a structure by a Vibration Damper. If we consider the frequency response shown on FIG. 6 as corresponding to a structure with an attached Vibration Damper, we would say by Eq. (2) that the Damper achieves an equivalent damping of ζ.sub.eq=0.061, see the caption to FIG. 6.

3 VIBRATION DAMPERS: DETAILED DESCRIPTION

[0083] 3.1 Types of Dampers

[0084] As mentioned above, a structure without a Damper can be represented as a mass on a spring, see FIG. 1.

[0085] A Traditional Damper, also known in the prior art as a TMD, see FIG. 2, consists of a single mass m.sub.1 attached to structure by the elastic stiffness k.sub.1 and the damping coefficient c.sub.1. Traditional Dampers have been in use for many years and can significantly reduce structure vibrations. The Damper must however be precisely tuned for the specific structure eigenfrequency f.sub.0 and mass m.sub.0, meaning that the Traditional Damper is rather inflexible and costly, with major costs associated with precise measurements of the structure properties and subsequent Damper adjustments.

[0086] The TG Broadband Damper according to the invention, see FIG. 3, is a Series Damper. It comprises two masses attached to a structure in series, with one mass m.sub.1 connected to the structure m.sub.0 through an elastic stiffness k.sub.1 and a damping c.sub.1, and another mass m.sub.2 connected to m.sub.1 through an elastic stiffness k.sub.2 and a damping c.sub.2. In other words, the damper according to the invention comprises a first damping unit, comprising a first damping body having a first mass m.sub.1, a first spring element having a first spring constant k.sub.1 and a first damping element having a first damping constant c.sub.1, wherein said first damping body is configured to be attached to said structure via said first spring element and said first damping element; and a second damping unit, comprising a second damping body having a second mass m.sub.2, a second spring element having a second spring constant k.sub.2 and a second damping element having a second damping constant c.sub.2, wherein said second damping body is configured to be attached to said first damping body via said second spring element and said second damping element.

[0087] The TG Broadband Damper according to the invention is optimized for broadband action. Optimization procedures will be discussed below.

[0088] The purpose of each of the above-mentioned Dampers is to reduce vibrations of the structure, when it is exposed to an influence f from the outside world. The force f may represent both external forces and ground movements, e.g. foot loads, traffic loads, wind forces, ground accelerations, earthquakes or machine induced vibrations.

[0089] Dampers may look rather different from the sketches, FIGS. 2 and 3. For example, the structure may be a high tower performing horizontal vibrations in a vibration mode with modal mass m.sub.0 and frequency f.sub.0. The connections realized by means of the spring elements k.sub.1 and k.sub.2 may comprise springs or by pendulum-like suspensions, where gravity provides the stiffnesses k.sub.1 and k.sub.2. As another example, the mass m.sub.2 may be replaced by a liquid-filled container of effective mass m.sub.2. The damping coefficients c.sub.1 and c.sub.2 may be due to actual dashpots or due to some other source of friction. In each case, it is important to take the effective mass of each component into account. This can be computed using the methods presented in [2].

[0090] 3.2 Different Optimization Criteria for Tuning of Dampers

[0091] Dampers can be tuned with different optimization criteria in mind: [0092] One may minimize the maximum H.sub.∞ of the frequency response function or, equivalently, maximize the equivalent damping ratio ζ.sub.eq, see Eq. (2). The TG Broadband Damper is optimized for maximum ζ.sub.eq in this manner. [0093] One may minimize the 2 norm of H, i.e. H.sub.2=∫H.sup.2df, which minimizes the structure response variance under white-noise forcing. [0094] One may maximize the decay rate of free vibrations obtained by a hold-and-release experiment. This is sometimes referred to as a “stability” criterion in the engineering literature.

[0095] Furthermore, the Damper may be optimized with different structures or groups of structures in mind: [0096] The Damper may be Point Optimized, i.e. optimized for a single structure with predefined values of f.sub.0 and m.sub.0. This type of tuning has been employed in the tuning of the vast majority of existing Dampers. [0097] We introduce the concept of Ensemble Tuning, where the Damper is optimized for a group (an Ensemble) of structures, whose frequency f.sub.0 and mass m.sub.0 can both vary. Ensemble Tuning is characterized by the Ensemble Radius d.sub.e, which describes the allowed variation of f.sub.0 and m.sub.0. The TG Broadband Damper is Ensemble Tuned.

[0098] The definition of an Ensemble and the Ensemble Radius d.sub.e is illustrated in FIG. 7. The Ensemble is a set of structures with f.sub.0 and m.sub.0 varying around a set of parameters f.sub.0,nominal and m.sub.0,nominal, which is denoted the Nominal Structure Parameters. The performance of a TG Broadband Damper are defined as the worst-case value of ζ.sub.eq on the Ensemble.

[0099] 3.3 Parameters Describing the TG Broadband Damper

[0100] The TG Broadband Damper is a Series Damper, which is preferably Ensemble Tuned for maximum equivalent damping ζ.sub.eq over an Ensemble of Ensemble Radius d.sub.e, see Sections 3.1 and 3.2 and FIG. 3.

[0101] Referring to FIG. 3, the following definitions apply: The frequencies defined below may be either computed from the spring rates k.sub.1 and k.sub.2 or from numerical models using standard methods. Alternatively, the frequencies can be directly measured by experiment, and the effective spring rates can subsequently be calculated. The angular frequency of the isolated main structure is ω.sub.0 with

[00009]${\omega }_0=\sqrt{\frac{k_0}{m_0}}$

or equivalently, k.sub.0=m.sub.0ω.sub.0.sup.2. The angular frequency of m.sub.1, with m.sub.1 and m.sub.2 fixed together, is ω.sub.1 with

[00010]${\omega }_1=\sqrt{\frac{k_1}{m_1+m_2}}$

or equivalently, k.sub.1=(m.sub.1+m.sub.2)ω.sub.0.sup.2. The angular frequency of m.sub.2 is ω.sub.2 with

[00011]${\omega }_2=\sqrt{\frac{k_2}{m_2}}$

or equivalently, k.sub.2=m.sub.2ω.sub.2.sup.2.

[00012]$\begin{array}{cc}\mu =\frac{m_1+m_2}{m_0},{\mu }_2=\frac{m_2}{m_1+m_2},& \left(3\right)\end{array}$${\Omega }_1=\frac{{\omega }_1}{{\omega }_0},{\Omega }_2=\frac{{\omega }_2}{{\omega }_0},$${\zeta }_0=\frac{c_1}{2m_0{\omega }_0},{\zeta }_1=\frac{c_1}{2\left(m_1+m_2\right){\omega }_1},{\zeta }_2=\frac{c_2}{2m_2{\omega }_2}.$

[0102] The parameters have the following significance: The most fundamental parameter describing a Damper is the Mass Ratio μ, which essentially determines the price of the Damper. With higher μ, both the price and the effectiveness of the Damper increase. The frequency ratio Ω.sub.2 is a critical parameter for a Series Damper and can be used to distinguish between various types of Series Dampers. The nondimensional frequencies Ω.sub.1 and Ω.sub.2 (and their dimensional counterparts ω.sub.1 and ω.sub.2) describe the tuning of the masses m.sub.1 and m.sub.2. Lastly, the parameters ζ.sub.0, ζ.sub.1 and ζ.sub.2 describe the damping ratios associated with motion of each of the masses m.sub.0, m.sub.1 and m.sub.2, respectively.

[0103] Note that a given set of Damper parameters can be realized by many different physical embodiments. Consider for example an SD with m d.sub.2 replaced by an open liquid container, whose mass is 20% of the total mass of the Damper. Effectively (for a particular choice of contained geometry), one half of the liquid mass should be counted as m.sub.2, and the other half should be counted as part of m.sub.1, leading to an effective value of μ.sub.2 of μ.sub.2=10%. Practical methods for computing the effective mass of a complicated DOF are given in [2]. It is critical to base the calculation of the TG Broadband Damper parameters, Eqs. (3) on the effective masses of each Damper component.

[0104] In summary, a TG Broadband Damper is described by choosing the parameters μ, μ.sub.2, Ω.sub.1, Ω.sub.2, ζ.sub.1 and ζ.sub.2. The dimensional parameters of the TG Broadband Damper are then determined by using the Nominal Structure Parameters f.sub.0=f.sub.0,nominal and m.sub.0=m.sub.0,nominal.

[0105] 3.4 Procedure for Tuning the TG Broadband Damper

[0106] When designing a TG Broadband Damper for a specific application, one first selects a particular Mass Ratio μ and a particular Ensemble Radius d.sub.e.

[0107] An approximation to the appropriate TG Broadband Damper parameters μ.sub.2, Ω.sub.1, Ω.sub.2, ζ.sub.1 and ζ.sub.2, see Eqs. (3), is then computed from a set of approximate relations developed below in Sec. 4 by detailed theoretical analysis of the system. In order to get improved Damper efficiency, the precise values of μ.sub.2, Ω.sub.1, Ω.sub.2, ζ.sub.1 and ζ.sub.2 may be refined by numerical optimization as described below:

[0108] For the numerical optimization, any computational language can be used, preferably with built-in routines for non-linear optimization. For example, the GNU Octave routine sqp can be used. For a given set of TG Broadband Damper parameters (μ.sub.2, Ω.sub.1, Ω.sub.2, ζ.sub.1 and ζ.sub.2), the equivalent damping ζ.sub.eq is computed for a representative set of structures distributed within the Ensemble of Ensemble Radius d.sub.e. For example, a set of structures on the circular boundary of the Ensemble can be used, see FIG. 7. The equivalent Ensemble damping ζ.sub.eq is then taken as the lowest found value (the worst-case value) of ζ.sub.eq.

[0109] The equations needed for computing H.sub.∞ and subsequently ζ.sub.eq are given below in Sec. 4, together with equations for approximate values of μ.sub.2, Ω.sub.1, Ω.sub.2, ζ.sub.1 and ζ.sub.2 to be used as a starting-point for the Ensemble Tuning process.

4 DETAILED MECHANICAL ANALYSIS OF THE TG BROADBAND DAMPER

[0110] Below, we present a theoretical analysis of the TG Broadband Damper. Approximate tuning rules are derived, allowing the determination of TG Broadband Damper parameters, see Eqs. (3), for given values of μ and d.sub.e.

[0111] The tuning of the TG Broadband Damper should be based on the effective value of μ, i.e. disregarding parts of the Damper, which are effectively fixed to the structure. The following discussion applies to TG Broadband Dampers with 0.018≤μ≤0.25.

[0112] 4.1 Equations of Motion

[0113] Consider the TG Broadband Damper represented in FIG. 3 with the parameters defined in Eqs. (3). The positions x.sub.i with i=0, 1, 2 as functions of time are defined as follows: The position of m.sub.0 is denoted x.sub.0. The position of m.sub.1 relative to m.sub.0 is denoted x.sub.1. The position of m.sub.2 relative to m.sub.1 is denoted x.sub.2. In each case, a dot denotes a time derivative, e.g.

[00013]$\stackrel{.}{x}=\frac{\partial x}{\partial t}.$

The equations of motion follow from conservation of momentum for m.sub.0+m.sub.1+m.sub.2, m.sub.1+m.sub.2 and m.sub.2, respectively:

(m.sub.0+m.sub.1+m.sub.2){umlaut over (x)}.sub.0+(m.sub.1+m.sub.2){umlaut over (x)}.sub.1+m.sub.2{umlaut over (x)}.sub.2+c.sub.0{dot over (x)}.sub.0+k.sub.0x.sub.0=f,  (4a)

(m.sub.1+m.sub.2)({umlaut over (x)}.sub.0+{umlaut over (x)}.sub.1)+m.sub.2{umlaut over (x)}.sub.2+c.sub.1{dot over (x)}.sub.1+k.sub.1x.sub.1=0,  (4b)

m.sub.2({umlaut over (x)}.sub.0+{umlaut over (x)}.sub.1+{umlaut over (x)}.sub.2)+c.sub.2{dot over (x)}.sub.2+k.sub.2x.sub.2=0,  (4c)

[0114] For most applications, ζ.sub.0≈0, and a non-zero value of ζ.sub.0 is known to have little effect on the system dynamics. Furthermore, Series Dampers are typically most effective with ζ.sub.1<<1, corresponding to the fact that m.sub.1 acts as a means for channeling the vibration energy into the relative motion of m.sub.2, and this transfer is most effective, when ζ.sub.1≈0. We therefore assume ζ.sub.0=ζ.sub.1=0, i.e. c.sub.0=c.sub.1=0. Dividing the equations in (4) by m.sub.0, m.sub.1+m.sub.2 and m.sub.2, respectively, we rewrite (4),

[00014]$\begin{array}{cc}\left(1+\mu \right){\stackrel{.Math.}{x}}_0+\mu {\stackrel{.Math.}{x}}_1+\mu {\mu }_2{\stackrel{.Math.}{x}}_2+{\omega }_0^2{x}_0=\frac{f}{m_0},& \left(5a\right)\end{array}$$\begin{array}{cc}{\stackrel{.Math.}{x}}_0+{\stackrel{.Math.}{x}}_1+{\mu }_2{\stackrel{.Math.}{x}}_2+{\omega }_1^2{x}_1=0,& \left(5b\right)\end{array}$$\begin{array}{cc}{\stackrel{.Math.}{x}}_0+{\stackrel{.Math.}{x}}_1+{\stackrel{.Math.}{x}}_2+2{\zeta }_2{\omega }_2{x}_2+{\omega }_2^2{\stackrel{.}{x}}_2=0.& \left(5c\right)\end{array}$

[0115] 4.2 Frequency-Response Functions

[0116] In order to express the frequency-response function (see Eq. (1)), we assume harmonic motions at the angular frequency ω, so x.sub.a˜e.sup.iωt with α=0, 1, 2, and solve Eqs. (5). This is done successively as follows. We first express x.sub.2 from (5c) and insert the result into (5b), which yields x.sub.1, and these results are then inserting into (5a), yielding x.sub.0:

[00015]$\begin{array}{cc}{x}_2=H_2.Math.\left(x_0+x_1\right),\mathrm{with}{H}_2\left(\omega \right)=\frac{{\omega }^2}{{\omega }_2^2-{\omega }^2+2i{\zeta }_2{\omega }_2\omega },& \left(6a\right)\end{array}$$\begin{array}{cc}{x}_1=H_1.Math.x_0,\mathrm{with}{H}_1\left(\omega \right)=\frac{{\omega }^2\left(1+{\mu }_2{H}_2\right)}{{\omega }_1^2-{\omega }^2+\left(1+{\mu }_2{H}_2\right)},& \left(6b\right)\end{array}$$\begin{array}{cc}{x}_0=H_0.Math.\frac{f}{m_0{\omega }_0^2},\mathrm{with}{H}_0\left(\omega \right)=\frac{{\omega }_0^2}{{\omega }_0^2-{\omega }^2+\mu {\omega }^{2}D},\mathrm{with}& \left(6c\right)\end{array}$$\begin{array}{c}D\left(\omega \right)=\left(1+H_1\right)\left(1+{\mu }_2{H}_2\right)\\ =\frac{{\omega }_1^2\left(1+{\mu }_2{H}_2\right)}{{\omega }_1^2-{\omega }^2\left(1+{\mu }_2{H}_2\right)}.\end{array}$

[0117] 4.3 Approximate tuning rules for Ω.sub.1, μ.sub.2 and ζ.sub.2

[0118] Based on theoretical considerations, see e.g. [6] and [7], we obtain the following approximate relations for the tuning of the parameters Ω.sub.1, μ.sub.2 and ζ.sub.2, expressed as functions of Ω.sub.2. We consider the subsystem consisting of DOFs 1 and 2 as a traditional Tuned Mass Damper optimized for minimal relative motion under fixed amplitude base excitation and use results from [7]. The ratio of the masses within this subsystem is

[00016]$\frac{m_2}{m_1}=\frac{{\mu }_2}{1-{\mu }_2}.$

In the absence of m.sub.2, the vibration frequency of m.sub.1 relative to a fixed m.sub.0 is Ω.sub.1/√{square root over (1−μ.sub.2)}.

[0119] The shape of the frequency response function of the DOF 1-2 subsystem determines the properties of the assembled TG Broadband Damper. We use the results in [7], Section 4.4.2, for the optimal traditional damper optimized for fixed deflection base load excitation with minimal relative motion of the primary mass (in this case m.sub.1). The optimal frequency Ω.sub.1 follows from determining the mean frequency of [7], eq. (4.80). The frequency ratio Ω.sub.2/≤.sub.1 follows from [7], Eq. (4.78), and the optimal value of ζ.sub.2 follows from [7], Eq. (4.82). The estimated optimal parameters are

[00017]$\begin{array}{cc}\frac{1}{{\Omega }_1/\sqrt{1-{\mu }_2}}=\frac{1}{2}\sqrt{1-{\mu }_2}\left(\sqrt{1+\sqrt{\frac{1}{2}\frac{{\mu }_2}{1-{\mu }_2}}}+\sqrt{1-\sqrt{\frac{1}{2}\frac{{\mu }_2}{1-{\mu }_2}}}\right)& \left(7\right)\end{array}$$\begin{array}{cc}\frac{1}{{\Omega }_1/\sqrt{1-{\mu }_2}}=\sqrt{\left(1-{\mu }_2\right)\left(1-\frac{3}{2}{\mu }_2\right)}& \left(8\right)\end{array}$$\begin{array}{cc}{\zeta }_2^2=\frac{1}{8}\frac{{\mu }_2\left(1-{\mu }_2\right)\left(3-\sqrt{\frac{1}{2}\frac{{\mu }_2}{1-{\mu }_2}}\right)}{1-\frac{3}{2}{\mu }_2}& \left(9\right)\end{array}$

[0120] Solving Eq. (8) for μ.sub.2 and expanding Eq. (7) to lowest order in μ.sub.2, we get to very good approximation,

[00018]$\begin{array}{cc}{\Omega }_1=1& \left(10\right)\end{array}$$\begin{array}{cc}{\mu }_2\left({\Omega }_2\right)=\frac{2}{3}\left(1-{\Omega }_2^2\right)& \left(11\right)\end{array}$$\begin{array}{cc}{\zeta }_2^2=\frac{1}{8}\frac{{\mu }_2\left({\Omega }_2\right)\left(1-{\mu }_2\left({\Omega }_2\right)\right)\left(3-\sqrt{\frac{1}{2}\frac{{\mu }_2\left({\Omega }_2\right)}{1-{\mu }_2\left({\Omega }_2\right)}}\right)}{1-\frac{3}{2}{\mu }_2\left({\Omega }_2\right)}& \left(12\right)\end{array}$

[0121] 4.4 The estimate d.sub.e*(μ, Ω.sub.2) of the Ensemble Radius d.sub.e

[0122] In order to quantify the broadband action of the TG Broadband Damper, we estimate the damper effect at the in the edge of the Ensemble. The estimated Ensemble Radius will be denoted d.sub.e*. First, we Taylor expand the denominator of Eq. (6c) around ω=0 and evaluate the imaginary part in the worst-case direction of the Ensemble, with a reduced structure angular frequency ω.sub.0* and a reduced mass ratio m.sub.0, with

Ω.sub.0*=(1−d.sub.e*)ω.sub.0,μ*=(1−d.sub.e*)μ.  (13)

[0123] The resonances, i.e. the forcing frequencies ω, where the real part of the denominator of (6c) becomes zero, occur due to the lowest order expansion of the real part of v Eq. (6c) when ω.sub.0.sup.2*−(1+μ)ω.sup.2=0, so we consider the resonant forcing frequency

[00019]$\begin{array}{cc}\omega =\frac{{\omega }_0^{*}}{\sqrt{1+\mu }}.& \left(14\right)\end{array}$

[0124] If the TG Broadband Damper is to provide broadband action up to the Ensemble Radius d.sub.e, the imaginary part of the denominator of Eq. (6c) must be of the same magnitude as the imaginary part of the denominator at ω=ω.sub.0. Based on [7], Eq. 4.81, we have

[00020]$\frac{1}{H_{0,\max }}\approx \mu ,$

so we set

[00021]$\begin{array}{cc}.Math.\mathrm{Im}\left(\left(1-d_e^{*}\right)\frac{{\omega }^2}{{\omega }_0^2}D\right).Math.=\mu .& \left(15\right)\end{array}$

[0125] We then insert the Taylor expansion of D and isolate d.sub.e*,

[00022]$\begin{array}{cc}{\left(1-d_e^{*}\right)}^4=\frac{{\mu \left(1+\mu \right)}^{5/2}{\Omega }_2^3}{2{\zeta }_2\sqrt{{\mu }_2}},& \left(16\right)\end{array}$

leading to

[00023]$\begin{array}{cc}{d}_e^{*}=1-{\left(\frac{{\mu \left(1+\mu \right)}^{5/2}{\Omega }_2^3}{2{\zeta }_2\sqrt{{\mu }_2}}\right)}^{1/4}.& \left(17\right)\end{array}$

[0126] This is expressed as a function of μ and Ω.sub.2 alone by inserting (11) and (12),

[00024]$\begin{array}{cc}{d}_e^{*}\left(\mu ,{\Omega }_2\right)=1-{\left(\frac{9}{2}\frac{{\mu \left(1+\mu \right)}^{5/2}{\Omega }_2^4}{{\left(1-{\Omega }_2^2\right)}^{3/2}\sqrt{3+6{\Omega }_2-\sqrt{1+{\Omega }_2^2-2{\Omega }_2^4}}}\right)}^{1/4}.& \left(18\right)\end{array}$

[0127] Eq. (18) provides a good estimate of the Ensemble Radius d.sub.e=d.sub.e* and allows for tuning of a TG Broadband Damper. We are mainly interested in large Ensemble Radii, i.e. d.sub.e*≥37.5%, and small mass ratios, 1.8%≤μ≤25%.

5 SUMMARY OF THE ANALYSIS

[0128] The mechanical analysis of the damper has provided the approximate tuning rules in Eqs. (10), (11) and (12) to be preferably fulfilled. Furthermore, the estimate d.sub.e* of the Ensemble Radius, Eq. (18) has been analytically derived, based on the allowed deviation of f.sub.0 and m.sub.0 in the Ensemble. These equations can be used in one of the two following ways. In each case, the mass ratio μ is considered given and fixed. [0129] For a given choice of Ω.sub.2, the Ensemble Radius d.sub.e can be estimated by d.sub.e* as computed by Eq. (18), and the remaining TG Damper parameters can be computed by Eqs. (10), (11) and (12). The parameters may be further refined by numerical optimization as described in Section 3.4. [0130] If, on the other hand, the desired Ensemble Radius d.sub.e is given, Eq. (18) is numerically solved with d.sub.e*=d.sub.e to give the appropriate value of Ω.sub.2. Note that d.sub.e* is a decreasing function of Ω.sub.2, so a requirement d.sub.e*≥d.sub.e*′, where d.sub.e*′ is a given constant, is equivalent to a requirement that Ω.sub.2≤Ω.sub.2′, where d.sub.e*(μ, Ω.sub.2′)=d.sub.e*′. The value of Ω.sub.2=Ω.sub.2′ thus obtained is then used in Eqs. (10), (11) and (12) to give the remaining TG Broadband Damper parameters. The parameters may be further refined by numerical optimization as described in Section 3.4.

[0131] The damper according to the invention can be practically implemented in a variety of embodiments. Some preferred cases are described in the following with reference to FIGS. 8-45:

[0132] FIG. 8 shows a 1.sup.st practical embodiment of the damper according to the invention. In this schematic figure the first damping element is omitted since its damping constant is close to 0.

[0133] Synergistic Effects: [0134] The static deflection caused by gravity (vertical oriented damper) acting on the masses could be reduced by selecting a higher nominal frequency, f.sub.0, within the ensemble radius. Higher frequency leads to higher stiffness and decreased static deflection. [0135] The EOSD (broad band) enables a more stable configuration by selecting a higher nominal frequency, f.sub.0, within the ensemble radius. A higher frequency leads to a stiffer setup which is less sensitive to buckling, external vibrations etc. [0136] Mass of guides installed on the secondary damper mass would contribute to mass of the primary damper mass.

[0137] Elements:

[0138] 1) Structure (moving) to be damped

[0139] 2) Primary spring (corresponding to first spring element in this and all further embodiments)

[0140] 3) Primary damper mass, m.sub.1 (corresponding to first mass in this and all further embodiments)

[0141] 4) Secondary spring (corresponding to second spring element in this and all further embodiments)

[0142] 5) Secondary damper mass, m.sub.2 (corresponding to second mass in this and all further embodiments)

[0143] 6) Secondary damper (dashpot) (corresponding to second damping element in this and all further embodiments)

[0144] Description: [0145] The embodiment can damp vibrations in the horizontal and/or vertical plane. [0146] Frequency, f.sub.1 and f.sub.2, could be estimated by common theory or experimentally. [0147] The internal damping (ζ.sub.2) can be determined experimentally. [0148] The damper masses could be supported by guides.

[0149] FIG. 9 shows a 2.sup.nd practical embodiment of the damper according to the invention.

[0150] Synergistic Effects: [0151] In contrast to a traditional Tuned Liquid Dampers, all the liquid mass is exploited effectively, i.e. a part of the liquid mass contributes as the secondary damper mass and the rest as the primary damper mass, see [1]. [0152] Due to the above-mentioned effective mass usage, the present setup allows the use of more flow restrictions than in a traditional Tuned Liquid Damper, allowing for greater internal damping of the wave motions. This is a significant advantage, because sufficient wave damping is traditionally very difficult to obtain in Tuned Liquid Dampers. [0153] The above-mentioned flow restrictions may furthermore be used to lower the wave frequency, adding flexibility and tuning possibilities to the setup. [0154] Due to the broadband damper effect of the EOSD, the pendulum frequency may be set significantly higher than the eigenfrequency of the structure to be damped. This allows for shorter pendulum lengths for the shown pendulum embodiment of the EOSD in cases, where very long pendulums are impractical. [0155] Due to the broadband damper effect of the EOSD, the pendulum frequency may be set significantly lower than the eigenfrequency of the structure to be damped. This allows for larger liquid tank sizes for the shown embodiment of the EOSD with a sloshing liquid component in cases, where high structure frequencies would otherwise necessitate impractically small liquid tanks. [0156] This embodiment is similar to the 4.sup.th embodiment.

[0157] Elements:

[0158] 1) Structure (moving) to be damped

[0159] 2) Hinge (rotating joint)

[0160] 3) Hanger (wire, cable, chain, rod, bar, beam)

[0161] 4) Hinge (rotating joint)

[0162] 5) Part of the primary damper mass (pendulum)

[0163] 6) Liquid mass contributing both to the secondary damper mass and to the primary damper mass

[0164] 7) Submerged obstacles such as gravel, perforated geometries, wires, tubes

[0165] 8) Liquid tank/container

[0166] 9) Rigid or flexible connection between liquid tank and primary damper mass

[0167] Description: [0168] The embodiment comprises two sub-structures: a pendulum (2,3,4,5) and a liquid tank (8). [0169] The embodiment can damp vibrations in the horizontal plane. [0170] Frequency, f.sub.1 and f.sub.2, could be estimated by common theory or experimentally. [0171] The internal damping (ζ.sub.2) is determined experimentally. [0172] The secondary damper equivalent 1-dof mass m.sub.2 can be determined experimentally. [0173] Damping (ζ.sub.2) is generated with obstacles submerged into the liquid. The mass of the obstacles contributes to the primary damper mass.

[0174] FIG. 10 shows a 3.sup.rd practical embodiment of the damper according to the invention.

[0175] Synergistic Effects:

[0176] This embodiment has synergistic effects similar to the 2.sup.nd embodiment.

[0177] Elements:

[0178] 1) Structure (moving) to be damped

[0179] 2) Hinge (rotating joint)

[0180] 3) Hanger (wire, cable, chain, rod, bar, beam)

[0181] 4) Hinge (rotating joint)

[0182] 5) Liquid tank/container

[0183] 6) Liquid mass contributing both to the secondary damper mass and to the primary damper mass

[0184] 7) Submerged obstacles such as gravel, perforated geometries, wires, tubes

[0185] Description:

[0186] This embodiment has synergistic to the 2.sup.nd embodiment.

[0187] FIG. 11 shows a 4.sup.th practical embodiment of the damper according to the invention.

[0188] Synergistic Effects: [0189] This embodiment is similar to the 2.sup.nd embodiment. [0190] The flexible connection between liquid tank and pendulum mass may lower liquid sloshing frequencies, while still exploiting the all of the liquid mass and possibly achieving a higher contribution to the secondary damper mass. [0191] A low nominal frequency, f.sub.0, allows for longer pendulum lengths for the shown pendulum embodiment of the EOSD in cases, where very short pendulums are impractical.

[0192] Elements:

[0193] 1) Structure (moving) to be damped

[0194] 2) Hinge (rotating joint)

[0195] 3) Hanger (wire, cable, chain, rod, bar, beam)

[0196] 4) Hinge (rotating joint)

[0197] 5) Liquid tank/container

[0198] 6) Liquid mass contributing both to the secondary damper mass and to the primary damper mass

[0199] 7) Submerged obstacles such as gravel, perforated geometries, wires, tubes

[0200] 8) Additional spring

[0201] 9) Rigid or flexible connection between liquid tank and primary damper mass

[0202] Description: [0203] Similar to the 2.sup.nd embodiment. [0204] The additional tension spring enables large displacements for high frequency dampers, by using long pendulum length and compensate loss of stiffness with a spring. [0205] The flexible connection between liquid tank and pendulum mass enables lower liquid sloshing frequencies.

[0206] FIG. 12 shows a 5.sup.th practical embodiment of the damper according to the invention.

[0207] Synergistic Effects:

[0208] This embodiment has synergistic to the 2.sup.nd embodiment and similar to the 4.sup.th embodiment.

[0209] Elements:

[0210] 1) Structure (moving) to be damped

[0211] 2) Hinge (rotating joint)

[0212] 3) Hanger (wire, cable, chain, rod, bar, beam)

[0213] 4) Hinge (rotating joint)

[0214] 5) Liquid tank/container

[0215] 6) Liquid mass contributing both to the secondary damper mass and to the primary damper mass

[0216] 7) Submerged obstacles such as gravel, perforated geometries, wires, tubes

[0217] 8) Additional spring

[0218] 9) Rigid or flexible connection between liquid tank and primary damper mass

[0219] Description: [0220] This embodiment is similar to the 2.sup.nd embodiment. [0221] The additional tension spring enables large displacements for high frequency dampers, by using long pendulum length and compensate loss of stiffness with a spring. [0222] The additional spring enables simple frequency adjustment, as the horizontal stiffness contribution from the spring (8) is proportional with the spring preload. [0223] Compression springs could reduce the frequency, f.sub.1, which can be advantageous for low frequency dampers, i.e. dampers with shorter pendulum lengths. [0224] The flexible connection between liquid tank and pendulum mass enables lower liquid sloshing frequencies.

[0225] FIG. 13 shows a 6.sup.th practical embodiment of the damper according to the invention.

[0226] Synergistic Effects: [0227] Due to the broadband damper effect of the EOSD, the pendulum frequency may be set significantly higher than the eigenfrequency of the structure to be damped. This allows for shorter pendulum lengths for the shown pendulum embodiment of the EOSD in cases, where very long pendulums are impractical. [0228] The pendulum frequency may be set significantly lower than the eigenfrequency of the structure to be damped. This allows for longer pendulum lengths for the shown pendulum embodiment of the EOSD in cases, where very short pendulums are impractical.

[0229] Elements:

1) Structure (moving) to be damped
2) Hinge (rotating joint)
3) Hanger (wire, cable, chain, rod, bar, beam)
4) Hinge (rotating joint)
5) Primary damper mass
6) Hinge (rotating joint)
7) Hanger (wire, cable, chain, rod, bar, beam)
8) Hinge (rotating joint)
9) Secondary damper mass
10) Secondary damper (dashpot) or shear damping element (friction, magnet, viscous, viscoelastic, rubber, elastomer).

[0230] Description: [0231] The embodiment comprises two sub-structures: a primary pendulum (2,3,4,5) and a secondary pendulum (6,7,8,9) [0232] The embodiment can damp vibrations in the horizontal plane. [0233] Frequency f.sub.1 and f.sub.2 of the pendulums are estimated by common theory or experimentally. [0234] Damping (ζ.sub.2) can be determined experimentally. [0235] Damping (ζ.sub.2) can be achieved with a dashpot or shear damping elements (friction, magnet, viscous, viscous-elastic, rubber, elastomer).

[0236] FIG. 14 shows a 7.sup.th practical embodiment of the damper according to the invention.

[0237] Synergistic Effects: [0238] In contrast to a traditional liquid type damper, all the liquid mass can be exploited effectively, i.e. a part of the liquid mass contributes as the secondary damper mass and the rest as the primary damper mass, see [2]. [0239] Due to the above-mentioned effective mass usage, the present setup allows the use of more flow restrictions than in a traditional liquid type damper, allowing for greater internal damping of the oscillator. [0240] The above-mentioned flow restrictions may furthermore be used to lower the submerged oscillator frequency, adding flexibility and tuning possibilities to the setup. [0241] The interaction between mass contributions to primary and secondary damper masses, enables advantageous tuning properties for the inverse pendulum, while still exploiting the all of the liquid mass. [0242] Synergistic effects similar to the 6.sup.th embodiment.

[0243] Elements:

[0244] 1) Structure (moving) to be damped

[0245] 2) Hinge (rotating joint)

[0246] 3) Hanger (wire, cable, chain, rod, bar, beam)

[0247] 4) Hinge (rotating joint)

[0248] 5) Liquid tank/container

[0249] 6) Submerged damper mass contributing to the secondary damper mass.

[0250] 7) Liquid mass contributing both to the secondary damper mass and to the primary damper mass

[0251] 8) Secondary spring

[0252] Description: [0253] The embodiment comprises two sub-structures: a pendulum (2,3,4,5) and a submerged oscillator (6,8) [0254] The embodiment can damp vibrations in the horizontal plane. [0255] Frequency f.sub.1 and f.sub.2 of could be determined experimentally. [0256] Damping (ζ.sub.2) can be determined experimentally. [0257] Damping (ζ.sub.2) can be achieved with a dashpot or shear damping elements (friction, magnet, viscous, viscous-elastic, rubber, elastomer). [0258] The primary and secondary damper equivalent 1-dof masses could be determined experimentally. [0259] Damping (ζ.sub.2) can be generated by fluid dynamic energy loss and flow restrictions. [0260] The oscillator (6,8) could be supported by guides.

[0261] FIG. 15 shows an 8.sup.th practical embodiment of the damper according to the invention.

[0262] Synergistic Effects: [0263] This embodiment has synergistic effects similar to the 6.sup.th embodiment [0264] Mass of guides installed on the secondary damper mass would contribute to mass of the primary damper mass.

[0265] Elements:

[0266] 1) Structure (moving) to be damped

[0267] 2) Hinge (rotating joint)

[0268] 3) Hanger (wire, cable, chain, rod, bar, beam)

[0269] 4) Hinge (rotating joint)

[0270] 5) Primary damper mass

[0271] 6) Secondary spring

[0272] 7) Secondary mass

[0273] 8) Secondary dashpot

[0274] Description: [0275] The embodiment comprises two sub-structures: a pendulum (2,3,4,5) and a damped oscillator (6,7,8) [0276] The embodiment can damp vibrations in the horizontal plane. [0277] Frequency f.sub.1 and f.sub.2 of could be determined experimentally or by theory. [0278] Damping (ζ.sub.2) can be determined experimentally. [0279] The oscillator (6,7,8) could be supported by guides.

[0280] FIG. 16 shows a 9.sup.th practical embodiment of the damper according to the invention.

[0281] Synergistic Effects: [0282] This embodiment has synergistic effects similar to the 6.sup.th embodiment. [0283] The EOSD (broad band) enables a more stable configuration by selecting a higher nominal frequency, f.sub.0, within the ensemble radius. A higher frequency leads to a stiffer setup which can be less sensitive to buckling, external vibrations etc. [0284] Mass of guides installed on the secondary damper mass would contribute to mass of the primary damper mass, enabling full exploitation of element masses.

[0285] Elements: [0286] 1) Structure (moving) to be damped [0287] 2) Hinge (rotating joint) [0288] 3) Hanger (wire, cable, chain, rod, bar, beam) [0289] 4) Hinge (rotating joint) [0290] 5) Primary damper mass [0291] 6) Elastic element (beam, bar, rod, leaf spring). [0292] 7) Shear damping element (friction, magnet, viscous, viscous-elastic, rubber, elastomer) connected between pendulum mass and secondary damper mass [0293] 8) Secondary damper mass

[0294] Description: [0295] The embodiment comprises two sub-structures: a pendulum (2,3,4,5) and a damped oscillator (6,7,8) [0296] The embodiment can damp vibrations in the horizontal plane. [0297] Frequency f.sub.1 and f.sub.2 of could be determined experimentally or by theory. [0298] Damping (ζ.sub.2) can be determined experimentally.

[0299] FIG. 17 shows a 10.sup.th practical embodiment of the damper according to the invention.

[0300] Synergistic Effects: [0301] This embodiment has synergistic effects similar to the 4.sup.th embodiment. [0302] The flexible connection between secondary damper mass and pendulum mass enables lower frequencies, while still exploiting the secondary mass and possibly achieving a higher contribution to the secondary damper mass.

[0303] Elements:

[0304] 1) Structure (moving) to be damped

[0305] 2) Hinge (rotating joint)

[0306] 3) Hanger (wire, cable, chain, rod, bar, beam)

[0307] 4) Hinge (rotating joint)

[0308] 5) Liquid tank/container

[0309] 6) Liquid mass contributing both to the secondary damper mass and to the primary damper mass

[0310] 7) Submerged obstacles such as gravel, perforated geometries, wires, tubes

[0311] 8) Rolling joint (roller/sliding bearing) connecting (9) and (14)

[0312] 9) Pendulum mass contributing to primary damper mass

[0313] 10) Hinge (rotating joint)

[0314] 11) Hinge (rotating joint)

[0315] 12) Rigid rod, bar, beam

[0316] 13) Rigid or flexible connection between liquid tank and primary damper mass

[0317] 14) Inverse pendulum mass contributing to primary damper mass

[0318] Description: [0319] The embodiment comprises three sub-structures: pendulum (2,3,4,9), inverse pendulum (10,11,12,14) and liquid tank (5,6,7). [0320] The embodiment can damp vibrations in the horizontal plane. [0321] Frequency f.sub.1 and f.sub.2 of could be determined experimentally. [0322] Damping (ζ.sub.2) can be determined experimentally. [0323] The inverse pendulum enables lower frequencies for pendulums. [0324] The secondary damper equivalent 1-dof mass m.sub.2 is determined experimentally.

[0325] FIG. 18 shows a 11.sup.th practical embodiment of the damper according to the invention.

[0326] Synergistic Effects: [0327] This embodiment has synergistic effects similar to the 10.sup.th embodiment. [0328] The interaction between mass contributions to primary and secondary damper masses, enables advantageous tuning properties for the inverse pendulum, while still exploiting the all of the liquid mass.

[0329] Elements:

[0330] 1) Structure (moving) to be damped

[0331] 2) Hinge (rotating joint)

[0332] 3) Hanger (wire, cable, chain, rod, bar, beam)

[0333] 4) Hinge (rotating joint)

[0334] 5) Liquid tank/container

[0335] 6) Liquid mass contributing both to the secondary damper mass and to the primary damper mass

[0336] 7) Submerged obstacles such as gravel, perforated geometries, wires, tubes

[0337] 8) Rolling joint (roller/sliding bearing) connecting (9) and (14)

[0338] 9) Pendulum mass contributing to primary damper mass

[0339] 10) Hinge (rotating joint)

[0340] 11) Hinge (rotating joint)

[0341] 12) Rod, bar, beam

Description:

[0342] The embodiment comprises two sub-structures: a pendulum (2,3,4,9) and a liquid tank (5,6,7). [0343] The embodiment can damp vibrations in the horizontal plane. [0344] Frequency f.sub.1 and f.sub.2 of could be determined experimentally. [0345] Damping (ζ.sub.2) can be determined experimentally. [0346] The inverse pendulum enables lower frequencies for pendulums. [0347] The secondary damper equivalent 1-dof mass m.sub.2 is determined experimentally.

[0348] FIG. 19 shows a 12.sup.th practical embodiment of the damper according to the invention.

[0349] Synergistic Effects: [0350] This embodiment has synergistic effects similar to the 6.sup.th embodiment. [0351] Mass of bearings would contribute to mass of the primary damper mass, enabling full exploitation of element masses.

[0352] Elements:

[0353] 1) Structure (moving) to be damped

[0354] 2) Hinge (rotating joint)

[0355] 3) Hanger (wire, cable, chain, rod, bar, beam)

[0356] 4) Hinge (rotating joint)

[0357] 5) Primary damper mass

[0358] 6) Bearings with curved track or bearings following a curved track or guide.

[0359] 7) Secondary damper (dashpot)

[0360] 8) Secondary damper mass

[0361] Description: [0362] The embodiment comprises two sub-structures: a pendulum (2,3,4,5) and a bearing supported mass (6,7,8). [0363] The embodiment can damp vibrations in the horizontal plane. [0364] Frequency f.sub.1 and f.sub.2 of could be determined experimentally. [0365] Damping (ζ.sub.2) can be determined experimentally. [0366] As the secondary damper mass moves horizontally, the curved track the forces the secondary mass upwards contributing to a change in potential energy, i.e. the restoring force (stiffness) is gravity based. [0367] Damping (ζ.sub.2) can be achieved with a dashpot or shear damping elements (friction, magnet, viscous, viscous-elastic, rubber, elastomer).

[0368] FIG. 20 shows a 13.sup.th practical embodiment of the damper according to the invention.

[0369] Synergistic Effects: [0370] This embodiment has synergistic effects similar to the 6.sup.th embodiment. [0371] Mass of the elastic bodies would contribute to mass of the primary damper mass, enabling full exploitation of element masses.

[0372] Elements:

[0373] 1) Structure (moving) to be damped

[0374] 2) Hinge (rotating joint)

[0375] 3) Hanger (wire, cable, chain, rod, bar, beam)

[0376] 4) Hinge (rotating joint)

[0377] 5) Primary damper mass

[0378] 6) Elastic body/element able to shear, e.g. coil spring, elastomer pad/bearing, elastomer, laminated pad/bearing, sandwich element

[0379] 7) Secondary damper mass

[0380] Description: [0381] The embodiment comprises two sub-structures: a pendulum (2,3,4,5) and a damped oscillator (6,7). [0382] The embodiment can damp vibrations in the horizontal plane. [0383] Frequency f.sub.1 and f.sub.2 of could be determined experimentally. [0384] Damping (ζ.sub.2) can be determined experimentally. [0385] Damping (ζ.sub.2) could be generated by friction in shearing the elastic body.

[0386] FIG. 21 shows a 14.sup.th practical embodiment of the damper according to the invention.

[0387] Synergistic Effects: [0388] This embodiment has synergistic effects similar to the 4.sup.th embodiment. [0389] Mass of the rigid elements (6) could contribute to mass of the primary damper mass.

[0390] Elements:

[0391] 1) Structure (moving) to be damped

[0392] 2) Hinge (rotating joint)

[0393] 3) Hanger (wire, cable, chain, rod, bar, beam)

[0394] 4) Hinge (rotating joint)

[0395] 5) Hinge (rotating joint)

[0396] 6) Rigid element enabling a fixed connection between (4,5)

[0397] 7) Hinge (rotating joint)

[0398] 8) Liquid mass contributing both to the secondary damper mass and to the primary damper mass

[0399] 9) Submerged obstacles such as gravel, perforated geometries, wires, tubes

[0400] 10) Liquid tank

[0401] 11) Hanger (wire, cable, chain, rod, bar, beam)

[0402] Description: [0403] The embodiment comprises two sub-structures: a double pendulum (2,3,4,5,6,7,11) and a liquid tank (10). [0404] The embodiment can damp vibrations in the horizontal plane. [0405] Frequency f.sub.1 and f.sub.2 of could be determined experimentally. [0406] The secondary damper equivalent 1-dof mass m.sub.2 is determined experimentally. [0407] Damping (ζ.sub.2) can be determined experimentally. [0408] Damping (ζ.sub.2) can be generated with obstacles submerged into the liquid. The mass of the obstacles contributes to the primary damper mass. [0409] The rigid element (6) enables reduced height for long pendulum lengths, i.e. combing two pendulum lengths (3,11).

[0410] FIG. 22 shows a 15.sup.th practical embodiment of the damper according to the invention.

[0411] Synergistic Effects: [0412] This embodiment has synergistic effects similar to the 14.sup.th embodiment. [0413] Mass of the rigid elements (15) would contribute to mass of the primary damper mass.

[0414] Elements:

[0415] 1) Structure (moving) to be damped

[0416] 2) Hinge (rotating joint)

[0417] 3) Hanger (wire, cable, chain, rod, bar, beam)

[0418] 4) Hinge (rotating joint)

[0419] 5) Rigid element enabling a fixed connection between (4,6)

[0420] 6) Hinge (rotating joint)

[0421] 7) Hinge (rotating joint)

[0422] 8) Hanger (wire, cable, chain, rod, bar, beam)

[0423] 9) Primary damper mass

[0424] 10) Hinge (rotating joint)

[0425] 11) Hanger (wire, cable, chain, rod, bar, beam)

[0426] 12) Hinge (rotating joint)

[0427] 13) Hinge (rotating joint)

[0428] 14) Hanger (wire, cable, chain, rod, bar, beam)

[0429] 15) Rigid element enabling a fixed connection between (12,13)

[0430] 16) Hinge (rotating joint)

[0431] 17) Liquid tank

[0432] 18) Liquid mass contributing both to the secondary damper mass and to the primary damper mass

[0433] 19) Submerged obstacles such as gravel, perforated geometries, wires, tubes

[0434] Description: [0435] The embodiment comprises three sub-structures: double pendulum (2,3,4,5,6,7,8,9), double pendulum (10,11,12,13,14,15,16) and a liquid tank (17). [0436] The embodiment can damp vibrations in the horizontal plane. [0437] Frequency f.sub.1 and f.sub.2 of could be determined experimentally. [0438] The secondary damper equivalent 1-dof mass m.sub.2 is determined experimentally. [0439] Damping (ζ.sub.2) can be determined experimentally. [0440] Damping (ζ.sub.2) can be generated with obstacles submerged into the liquid. The mass of the obstacles contributes to the primary damper mass. [0441] The rigid elements (5,15) enables reduced height for long pendulum lengths, i.e. combing to pendulum lengths.

[0442] FIG. 23 shows a 16.sup.th practical embodiment of the damper according to the invention.

[0443] Synergistic Effects: [0444] This embodiment has synergistic effects similar to the 7.sup.th embodiment. [0445] The interaction between mass contributions to primary and secondary damper masses, enables advantageous tuning properties for the submerged pendulum, while still exploiting the all of the liquid mass.

[0446] Elements:

[0447] 1) Structure (moving) to be damped

[0448] 2) Hinge (rotating joint)

[0449] 3) Hanger (wire, cable, chain, rod, bar, beam)

[0450] 4) Hinge (rotating joint)

[0451] 5) Liquid tank/container

[0452] 6) Hinge (rotating joint)

[0453] 7) Hanger (wire, cable, chain, rod, bar, beam)

[0454] 8) Hinge (rotating joint)

[0455] 9) Submerged secondary damper mass

[0456] 10) Liquid mass (Liquid tank/container) contributing both to the secondary damper mass and to the primary damper mass

[0457] Description: [0458] The embodiment comprises three sub-structures: primary pendulum (2,3,4), liquid tank (5) and submerged pendulum (6,7,8,9). [0459] The embodiment can damp vibrations in the horizontal plane. [0460] Frequency f.sub.1 and f.sub.2 of could be determined experimentally. [0461] The primary and secondary damper equivalent 1-dof mass could be determined experimentally. [0462] Damping (ζ.sub.2) can be determined experimentally. [0463] Damping (ζ.sub.2) can be generated by fluid dynamic energy loss and flow restrictions

[0464] FIG. 24 shows a 17.sup.th practical embodiment of the damper according to the invention.

[0465] Synergistic Effects: [0466] The static deflection caused by gravity (vertical oriented damper) acting on the masses can be reduced by selecting a higher nominal frequency, f.sub.0, within the ensemble radius. Higher frequency leads to higher stiffness and decreased static deflection. [0467] The rotation of the primary damper mass lead to lower frequencies, which can be advantageous for low frequency damper designs. [0468] The EOSD (broad band) enables a more stable configuration by selecting a higher nominal frequency, f.sub.0, within the ensemble radius. A higher frequency leads to a stiffer setup which can be less sensitive to buckling, external vibrations etc. [0469] Mass of the damping and elastic elements would contribute to mass of the primary damper mass, enabling full exploitation of element masses (4,5).

[0470] Elements:

[0471] 1) Structure (moving) to be damped

[0472] 2) Flexible/elastic element (beam, bar, rod, leaf spring).

[0473] 3) Primary damper mass which can be movable along the elastic element to obtain frequency adjustment.

[0474] 4) Shear damping element (friction, magnet, viscous, viscous-elastic, rubber, elastomer).

[0475] 5) Flexible/elastic element (beam, bar, rod, leaf spring).

[0476] 6) Secondary damper mass which can be movable along the elastic element to obtain frequency adjustment.

[0477] Description: [0478] The embodiment can damp vibrations in the horizontal plane and/or vertical plane by rotating the damper. [0479] Frequency f.sub.1 and f.sub.2 of could be determined experimentally. [0480] The primary and secondary damper equivalent 1-dof mass could be determined experimentally. [0481] Damping (ζ.sub.2) can be determined experimentally. [0482] The movable masses are fixed onto the elastic element when the desired frequency can be achieved. [0483] The damper mass gravitational center could be offset from where the mass can be fixed to elastic element.

[0484] FIG. 25 shows a 18.sup.th practical embodiment of the damper according to the invention.

[0485] Synergistic Effects:

[0486] This embodiment has synergistic effects similar to the 17.sup.th embodiment.

[0487] Elements:

[0488] 1) Structure (moving) to be damped.

[0489] 2) Flexible/elastic element (beam, bar, rod, leaf spring).

[0490] 3) Primary damper mass which can be movable along the elastic element to obtain frequency adjustment.

[0491] 4) Shear damping element (friction, magnet, viscous, viscous-elastic, rubber, elastomer).

[0492] 5) Flexible/elastic element (beam, bar, rod, leaf spring).

[0493] 6) Secondary damper mass which can be movable along the elastic element to obtain frequency adjustment.

[0494] 7) Additional spring

[0495] Description: [0496] The embodiment can damp vibrations in the horizontal plane and/or vertical plane by rotating the damper. [0497] Frequency f.sub.1 and f.sub.2 of could be determined experimentally. [0498] The primary and secondary damper equivalent 1-dof mass could be determined experimentally. [0499] Damping (ζ.sub.2) can be determined experimentally. [0500] The movable masses are fixed onto the elastic element when the desired frequency can be achieved. [0501] The damper mass gravitational center could be offset from where the mass can be fixed to elastic element.

[0502] FIG. 26 shows a 19.sup.th practical embodiment of the damper according to the invention.

[0503] Synergistic Effects:

[0504] This embodiment has synergistic effects similar to the 4.sup.th embodiment.

[0505] Elements:

[0506] 1) Structure (moving) to be damped

[0507] 2) Concave surface

[0508] 3) Part of the primary damper mass (liquid tank) sphere, cylinder shaped.

[0509] 4) Liquid mass contributing both to the secondary damper mass and to the primary damper mass

[0510] 5) Submerged obstacles such as gravel, perforated geometries, wires, tubes

[0511] Description: [0512] The embodiment comprises a rolling/rocking liquid tank/container (3) [0513] The embodiment can damp vibrations in the horizontal plane. [0514] Frequency f.sub.1 and f.sub.2 of could be determined experimentally. [0515] The primary and secondary damper equivalent 1-dof masses could be determined experimentally. [0516] Damping (ζ.sub.2) can be determined experimentally. [0517] Damping (ζ.sub.2) could be generated with obstacles submerged into the liquid. The mass of the obstacles contributes to the primary damper mass. [0518] As the primary damper mass moves horizontally, the curved track forces the secondary mass upwards contributing to a change in potential energy, i.e. the restoring force (stiffness) is gravity based.

[0519] FIG. 27 shows a 20.sup.th practical embodiment of the damper according to the invention.

[0520] Synergistic Effects:

[0521] The synergistic (Tuned Liquid damper) effects are similar to the 4.sup.th embodiment.

[0522] Elements:

[0523] 1) Structure (moving) to be damped

[0524] 2) Sphere or cylinder

[0525] 3) Part of the primary damper mass (liquid tank) sphere, cylinder shaped.

[0526] 4) Liquid mass contributing both to the secondary damper mass and to the primary damper mass

[0527] 5) Submerged obstacles such as gravel, perforated geometries, wires, tubes

[0528] Description: [0529] The embodiment contains a rolling/rocking liquid tank/container (3) [0530] The embodiment can damp vibrations in the horizontal plane. [0531] The rocking frequency, f.sub.1, can be estimated by common theory [0532] The fundamental liquid sloshing frequency, f.sub.2, can be determined experimentally. [0533] The secondary damper equivalent 1-dof mass m.sub.2 is determined experimentally. [0534] Internal damping (ζ.sub.2) is generated with obstacles submerged into the liquid. The mass of the obstacles contributes to the primary damper mass. [0535] The internal damping (ζ.sub.2) is determined experimentally. [0536] As the primary damper mass moves horizontally, the curved track forces the secondary mass upwards contributing to a change in potential energy, i.e. the restoring force (stiffness) is gravity based.

[0537] FIG. 28 shows a 21.sup.st practical embodiment of the damper according to the invention

[0538] Synergistic Effects:

[0539] This embodiment has synergistic effects similar to the 1.sup.st embodiment and the 4.sup.th embodiment (Tuned Liquid Damper).

[0540] Elements:

[0541] 1) Structure (moving) to be damped

[0542] 2) Primary spring

[0543] 3) Primary damper mass

[0544] 4) Additional spring

[0545] 5) Liquid tank/container

[0546] 6) Liquid mass contributing both to the secondary damper mass and to the primary damper mass

[0547] 7) Submerged obstacles such as gravel, perforated geometries, wires, tubes

[0548] Description: [0549] The embodiment contains two sub-structures: an approximately undamped oscillator (2,3,4) and a liquid tank (5,6,7). [0550] The embodiment can damp vibrations in the horizontal plane. [0551] The frequencies f.sub.1 and f.sub.2 can be estimated by common theory or experimentally. [0552] The internal damping (ζ.sub.2) can be determined experimentally. [0553] The mass m.sub.1 may be supported by guides. [0554] The secondary damper equivalent 1-dof mass m.sub.2 can be determined experimentally. [0555] Springs (4) oriented perpendicular to (2) enables simple frequency adjustment, as the horizontal spring stiffness contribution is proportional with the spring preload.

[0556] FIG. 29 shows a 22.sup.nd practical embodiment of the damper according to the invention

[0557] Synergistic Effects:

[0558] This embodiment has synergistic effects similar to the 1.sup.st embodiment and the 4.sup.th embodiment (Tuned Liquid Damper).

[0559] Elements:

[0560] 1) Structure (moving) to be damped

[0561] 2) Primary spring

[0562] 3) Primary damper mass

[0563] 4) Liquid tank/container

[0564] 5) Liquid mass contributing both to the secondary damper mass and to the primary damper mass

[0565] 6) Submerged obstacles such as gravel, perforated geometries, wires, tubes

[0566] Description: [0567] This embodiment contains two sub-structures: an approximately undamped oscillator (2,3) and a liquid tank (4,5,6). [0568] The embodiment can damp vibrations in the horizontal plane. [0569] The frequencies f.sub.1 and f.sub.2 can be estimated by common theory or experimentally. [0570] The internal damping (ζ.sub.2) can be determined experimentally. [0571] The mass m.sub.1 may be supported by guides. [0572] The secondary damper equivalent 1-dof mass m.sup.2 can be determined experimentally.

[0573] FIG. 30 shows a 23.sup.th practical embodiment of the damper according to the invention

[0574] Synergistic Effects:

[0575] This embodiment has synergistic effects similar to the 1.sup.st embodiment and the 6.sup.th embodiment.

[0576] Elements:

[0577] 1) Structure (moving) to be damped

[0578] 2) Primary spring

[0579] 3) Primary damper mass

[0580] 4) Hinge (rotating joint)

[0581] 5) Hanger (wire, cable, rod, bar, beam)

[0582] 6) Secondary damper mass

[0583] Description: [0584] The embodiment contains two sub-structures: An approximately undamped oscillator (2,3) and a damped pendulum (4,5,6). [0585] The embodiment can damp vibrations in the horizontal plane. [0586] The frequencies f.sub.1 and f.sub.2 can be estimated by common theory or experimentally. [0587] The internal damping (ζ.sub.2) can be determined experimentally. [0588] The mass m.sub.1 may be supported by guides. [0589] Internal damping (ζ.sub.2) could be generated in the rotating joint (4).

[0590] FIG. 31 shows a 24.sup.th practical embodiment of the damper according to the invention.

[0591] Synergistic Effects: [0592] This embodiment has synergistic effects similar to the 1.sup.st embodiment [0593] The mass of the elastic bodies (5) would contribute to m.sub.1, enabling full exploitation of element masses.

[0594] Elements:

[0595] 1) Structure (moving) to be damped

[0596] 2) Primary spring

[0597] 3) Primary damper mass

[0598] 4) Secondary damper mass

[0599] 5) Elastic element (beam, bar, rod, leaf spring).

[0600] 6) Shear damping element (friction, magnet, viscous, viscoelastic,

rubber, elastomer).

[0601] Description: [0602] The embodiment contains two sub-structures: An approximately undamped oscillator (2,3) and a damped pendulum (4,5,6). [0603] The embodiment can damp vibrations in the horizontal plane or in the vertical plane (by rotating the embodiment). [0604] The frequencies f.sub.1 and f.sub.2 can be estimated by common theory or experimentally. [0605] The internal damping (ζ.sub.2) can be determined experimentally. [0606] The mass m.sub.1 may be supported by guides. [0607] The secondary damper equivalent 1-dof mass m.sub.2 can be determined experimentally.

[0608] FIG. 32 shows a 25.sup.th practical embodiment of the damper according to the invention.

[0609] Synergistic Effects:

[0610] This embodiment has synergistic effects similar to the 1.sup.st embodiment

[0611] Elements:

[0612] 1) Structure (moving) to be damped

[0613] 2) Primary spring

[0614] 3) Primary damper mass

[0615] 4) Additional spring

[0616] 5) Secondary spring

[0617] 6) Secondary damper mass

[0618] 7) Secondary damper (dashpot)

[0619] Description: [0620] The embodiment can damp vibrations in the horizontal plane or in the vertical plane (by rotating the embodiment). [0621] The frequencies f.sub.1 and f.sub.2 can be estimated by common theory or experimentally. [0622] The internal damping (ζ.sub.2) can be determined experimentally. [0623] The masses m.sub.1 and m.sub.2 may be supported by guides.

[0624] FIG. 33 shows a 26.sup.th practical embodiment of the damper according to the invention.

[0625] Synergistic Effects: [0626] This embodiment has synergistic effects similar to the 1.sup.st embodiment [0627] The mass of the elastic bodies (5) would contribute to m.sub.1, enabling full exploitation of element masses.

[0628] Elements:

[0629] 1) Structure (moving) to be damped

[0630] 2) Primary spring

[0631] 3) Primary damper mass

[0632] 4) Secondary damper mass

[0633] 5) Elastic body/element able to shear, e.g. coil spring, elastomer pad/bearing, elastomer, laminated pad/bearing or sandwich element

[0634] Description: [0635] The embodiment contains two sub-structures: An approximately undamped oscillator (2,3) and a mass supported by an elastic body (4,5). [0636] The embodiment can damp vibrations in the horizontal plane or in the vertical plane (by rotating the embodiment). [0637] The frequencies f.sub.1 and f.sub.2 can be estimated by common theory or experimentally. [0638] The internal damping (ζ.sub.2) can be determined experimentally. [0639] The mass m.sub.1 may be supported by guides. [0640] Internal damping (ζ.sub.2) could be generated by friction in shearing the elastic body (4).

[0641] FIG. 34 shows a 27.sup.th practical embodiment of the damper according to the invention.

[0642] Synergistic Effects: [0643] This embodiment has synergistic effects similar to the 1.sup.st embodiment [0644] The mass of the bearings/guide would contribute to m.sub.1, enabling full exploitation of element masses.

[0645] Elements:

[0646] 1) Structure (moving) to be damped

[0647] 2) Primary spring

[0648] 3) Primary damper mass

[0649] 4) Secondary damper mass

[0650] 5) Bearings with curved track or bearings following a curved track or guide.

[0651] 6) Dashpot

[0652] Description: [0653] The embodiment contains two sub-structures: An approximately undamped oscillator (2,3) and a mass supported by bearings (4,5,6). [0654] The embodiment can damp vibrations in the horizontal plane. [0655] The frequencies f.sub.1 and f.sub.2 can be estimated by common theory or experimentally. [0656] The internal damping (ζ.sub.2) can be determined experimentally. [0657] The mass m.sub.1 may be supported by guides. [0658] As the secondary damper mass moves horizontally, the curved track forces the secondary mass upwards contributing to a change in potential energy, i.e. the restoring force (stiffness) is gravity based. [0659] Internal damping (ζ.sub.2) is achieved with a dashpot or shear damping elements (friction, magnet, viscous, viscoelastic, rubber, elastomer).

[0660] FIG. 35 shows a 28.sup.th practical embodiment of the damper according to the invention.

[0661] Synergistic Effects: [0662] This embodiment has synergistic effects similar to the 1.sup.st embodiment [0663] The mass of the bearing and the rigid part between the primary mass and the secondary mass would contribute to m.sub.1, enabling full exploitation of element masses.

[0664] Elements:

[0665] 1) Structure (moving) to be damped

[0666] 2) Hinge (Rotating joint, bearing)

[0667] 3) Rigid rod, bar, beam

[0668] 4) Hinge (Rotating joint, bearing)

[0669] 5) Rigid rod, bar, beam

[0670] 6) Secondary damper mass

[0671] 7) Dashpot

[0672] 8) Secondary spring

[0673] 9) Primary damper mass

[0674] 10) Primary spring

[0675] Description: [0676] This embodiment contains two sub-structures: An approximately undamped oscillator (2,3,9,10) and a damped oscillator (4,5,6,7,8), both with rotational guides. [0677] The embodiment can damp vibrations in the horizontal or vertical plane. (rotating the [0678] damper) [0679] The frequencies f.sub.1 and f.sub.2 can be estimated by common theory or experimentally. [0680] The internal damping (ζ.sub.2) can be determined experimentally. [0681] Internal damping (ζ.sub.2) could be generated in the rotating joint (4). [0682] The springs and dashpot could be movable to enable easy frequency and damping adjustment.

[0683] FIG. 36 shows a 29.sup.th practical embodiment of the damper according to the invention.

[0684] Synergistic Effects: [0685] This embodiment has synergistic effects similar to the 1.sup.th embodiment [0686] The mass of the elastic bodies (4) would contribute to the primary damper mass, enabling full exploitation of element masses.

[0687] Elements:

[0688] 1) Structure (moving) to be damped

[0689] 2) Elastic body/element able to shear, e.g. coil spring, elastomer pad/bearing, elastomer laminated pad/bearing, sandwich element

[0690] 3) Primary damper mass

[0691] 4) Elastic body/element able to shear, e.g. coil spring, elastomer pad/bearing, elastomer laminated pad/bearing, sandwich element

[0692] 5) Secondary damper mass

[0693] Description: [0694] The embodiment contains two sub-structures: A mass supported by an elastic body (2,3) and a mass supported by a damped elastic body (4,5) [0695] The embodiment can damp vibrations in the horizontal or vertical plane (by rotating the damper). [0696] The frequencies f.sub.1 and f.sub.2 can be estimated by common theory or experimentally. [0697] The internal damping (ζ.sub.2) can be determined experimentally. [0698] Internal damping (ζ.sub.2) could be generated by friction in shearing the elastic body (4).

[0699] FIG. 37 shows a 30.sup.th practical embodiment of the damper according to the invention.

[0700] Synergistic Effects:

[0701] This embodiment has synergistic effects similar to the 1.sup.st embodiment and the 4.sup.th embodiment (Tuned Liquid Damper).

[0702] Elements:

[0703] 1) Structure (moving) to be damped

[0704] 2) Elastic body/element able to shear, e.g. coil spring, elastomer pad/bearing, elastomer laminated pad/bearing, sandwich element

[0705] 3) Part of the primary damper mass (liquid tank).

[0706] 4) Liquid mass contributing both to the secondary damper mass and to the primary damper mass

[0707] 5) Submerged obstacles such as gravel, perforated geometries, wires, tubes

[0708] Description: [0709] The embodiment contains a liquid tank/container supported by an elastic body (2,3) [0710] The embodiment can damp vibrations in the horizontal or vertical plane (by rotating the [0711] damper) [0712] The frequencies f.sub.1 and f.sub.2 can be estimated by common theory or experimentally. [0713] The internal damping (ζ.sub.2) can be determined experimentally. [0714] Internal damping (ζ.sub.2) can be generated with obstacles submerged into the liquid. The mass of the obstacles contributes to the primary damper mass. [0715] The secondary damper equivalent 1-dof mass m.sub.2 can determined experimentally.

[0716] FIG. 38 shows a 31.sup.st practical embodiment of the damper according to the invention.

[0717] Synergistic Effects: [0718] This embodiment has synergistic effects similar to the 1.sup.st embodiment [0719] The mass of the elastic bodies (4) would contribute to m.sub.1, enabling full exploitation of element masses.

[0720] Elements:

[0721] 1) Structure (moving) to be damped

[0722] 2) Elastic body/element able to shear, e.g. coil spring, elastomer pad/bearing, elastomer laminated pad/bearing, sandwich element

[0723] 3) Primary damper mass

[0724] 4) Elastic element (beam, bar, rod, leaf spring).

[0725] 5) Secondary damper mass

[0726] 6) Shear damping element (friction, magnet, viscous, viscoelastic, rubber, elastomer) connected between primary and secondary damper mass

[0727] Description: [0728] The embodiment contains two sub-structures: A mass supported by an elastic body (2,3) and a damped oscillator (4,5,6) [0729] The embodiment may damp vibrations in the horizontal or vertical plane (by rotating the damper) [0730] The frequencies f.sub.1 and f.sub.2 can be estimated by common theory or experimentally. [0731] The internal damping (ζ.sub.2) can be determined experimentally. [0732] Internal damping (ζ.sub.2) could be generated by friction in shearing the elastic body (4). [0733] The secondary damper equivalent 1-dof mass m.sub.2 can be determined experimentally.

[0734] FIG. 39 shows a 32.sup.nd practical embodiment of the damper according to the invention.

[0735] Synergistic Effects:

[0736] This embodiment has synergistic effects similar to the 1.sup.st embodiment

[0737] Elements:

[0738] 1) Structure (moving) to be damped

[0739] 2) Elastic body/element able to shear, e.g. coil spring, elastomer pad/bearing, elastomer laminated pad/bearing, sandwich element

[0740] 3) Primary damper mass

[0741] 4) Hinge (rotating joint)

[0742] 5) Hanger (wire, cable, rod, bar, beam)

[0743] 6) Hinge (rotating joint)

[0744] 7) Secondary damper mass

[0745] Description: [0746] The embodiment contains two sub-structures: A mass supported by an elastic body (2,3) and a damped pendulum (4,5,6,7) [0747] The embodiment can damp vibrations in the horizontal plane. [0748] The frequencies f.sub.1 and f.sub.2 can be estimated by common theory or experimentally. [0749] The internal damping (ζ.sub.2) can be determined experimentally. [0750] Internal damping (ζ.sub.2) can be achieved with a dashpot or shear damping elements (friction, magnet, viscous, viscoelastic, rubber, elastomer).

[0751] FIG. 40 shows a 33.sup.rd practical embodiment of the damper according to the invention.

[0752] Synergistic Effects:

[0753] This embodiment has synergistic effects similar to the 1.sup.st embodiment

[0754] Elements:

[0755] 1) Structure (moving) to be damped

[0756] 2) Elastic body/element able to shear, e.g. coil spring, elastomer pad/bearing, elastomer laminated pad/bearing, sandwich element

[0757] 3) Primary damper mass

[0758] 4) Secondary spring

[0759] 5) Secondary damper mass

[0760] 6) Secondary dashpot

[0761] Description: [0762] The embodiment contains two sub-structures: A mass supported by an elastic body (2,3) and a damped oscillator (4,5,6) [0763] The embodiment can damp vibrations in the horizontal plane. [0764] The frequencies f.sub.1 and f.sub.2 can be estimated by common theory or experimentally. [0765] The internal damping (ζ.sub.2) can be determined experimentally.

[0766] FIG. 41 shows a 34.sup.th practical embodiment of the damper according to the invention.

[0767] Synergistic Effects: [0768] This embodiment has synergistic effects similar to the 6.sup.th embodiment [0769] The interaction between mass contributions to the primary and secondary damper masses enables advantageous tuning properties for the primary mass, see [2].

[0770] Elements:

[0771] 1) Structure (moving) to be damped

[0772] 2) Bearings with curved track or bearings following a curved track or guide.

[0773] 3) Primary damper mass

[0774] 4) Bearings with curved track or bearings following a curved track or guide.

[0775] 5) Secondary damper mass

[0776] 6) Dashpot

[0777] Description: [0778] The embodiment contains two sub-structures: A mass supported by bearings (2,3) and a mass supported by bearings (4,5) [0779] The embodiment can damp vibrations in the horizontal plane. [0780] The frequencies f.sub.1 and f.sub.2 can be estimated by common theory or experimentally. [0781] The internal damping (ζ.sub.2) can be determined experimentally. [0782] As the damper mass moves horizontally, the curved track forces the damper masses upwards contributing to a change in potential energy, i.e. the restoring force (stiffness) is gravity based. [0783] Internal damping (ζ.sub.2) is achieved with a dashpot or shear damping elements (friction, magnet, viscous, viscoelastic, rubber, elastomer).

[0784] FIG. 42 shows a 35.sup.th practical embodiment of the damper according to the invention.

[0785] Synergistic Effects: [0786] This embodiment has synergistic effects similar to the 6.sup.th embodiment [0787] Synergistic (Tuned Liquid damper) effects are similar to the 4.sup.th embodiment.

[0788] Elements:

[0789] 1) Structure (moving) to be damped

[0790] 2) Bearings with curved track or bearings following a curved track or guide.

[0791] 3) Liquid tank/container

[0792] 4) Liquid mass contributing both to the secondary damper mass and to the primary damper mass

[0793] 5) Submerged obstacles such as gravel, perforated geometries, wires, tubes

[0794] Description: [0795] The embodiment a liquid tank/container supported by bearings (2,3,4,5) [0796] The embodiment can damp vibrations in the horizontal plane. [0797] The frequencies f.sub.1 and f.sub.2 can be estimated by common theory or experimentally. [0798] The internal damping (ζ.sub.2) can be determined experimentally. [0799] As the primary damper mass moves horizontally, the curved track forces the damper masses upwards contributing to a change in potential energy, i.e. the restoring force (stiffness) is gravity based. [0800] The secondary damper equivalent 1-dof mass m.sub.2 is determined experimentally.

[0801] FIG. 43 shows a 36.sup.th practical embodiment of the damper according to the invention.

[0802] Synergistic Effects: [0803] This embodiment has synergistic effects similar to the 6.sup.th embodiment [0804] Damping could be generated by friction in shearing the elastic body (4).

[0805] Elements:

[0806] 1) Structure (moving) to be damped

[0807] 2) Bearings with curved track or bearings following a curved track or guide.

[0808] 3) Primary damper mass

[0809] 4) Elastic element (beam, bar, rod, leaf spring).

[0810] 5) Secondary damper mass

[0811] 6) Shear damping element (friction, magnet, viscous, viscoelastic, rubber, elastomer) connected between primary and secondary damper mass

[0812] Description: [0813] The embodiment contains two sub-structures: A mass supported by bearings (2,3) and a damped oscillator (4,5,6) [0814] The embodiment can damp vibrations in the horizontal plane. [0815] The frequencies f.sub.1 and f.sub.2 can be estimated by common theory or experimentally. [0816] The internal damping (ζ.sub.2) can be determined experimentally. [0817] Internal damping (ζ.sub.2) could be generated by friction in shearing the elastic body (4). [0818] As the primary damper mass moves horizontally, the curved track forces the damper masses upwards contributing to a change in potential energy, i.e. the restoring force (stiffness) is gravity based. [0819] The secondary damper equivalent 1-dof mass m.sub.2 is determined experimentally.

[0820] FIG. 44 shows a 37.sup.th practical embodiment of the damper according to the invention.

[0821] Synergistic Effects:

[0822] This embodiment has synergistic effects similar to the 6.sup.th embodiment

[0823] Elements:

[0824] 1) Structure (moving) to be damped

[0825] 2) Bearings with curved track or bearings following a curved track or guide.

[0826] 3) Primary damper mass

[0827] 4) Hinge (rotating joint)

[0828] 5) Hanger (wire, cable, rod, bar, beam)

[0829] 6) Hinge (rotating joint)

[0830] 7) Secondary damper mass

[0831] Description: [0832] The embodiment contains two sub-structures: A mass supported by bearings (2,3) and a damped pendulum (4,5,6,7). [0833] The embodiment can damp vibrations in the horizontal plane. [0834] The frequencies f.sub.1 and f.sub.2 can be estimated by common theory or experimentally. [0835] The internal damping (ζ.sub.2) can be determined experimentally. [0836] Internal damping (ζ.sub.2) is achieved with a dashpot or shear damping elements (friction, magnet, viscous, viscoelastic, rubber, elastomer). [0837] As the primary damper mass moves horizontally, the curved track forces the damper masses upwards contributing to a change in potential energy, i.e. the restoring force (stiffness) is gravity based.

[0838] FIG. 45 shows a 38.sup.th practical embodiment of the damper according to the invention.

[0839] Synergistic Effects:

[0840] This embodiment has synergistic effects similar to the 6.sup.th embodiment

[0841] Elements:

[0842] 1) Structure (moving) to be damped

[0843] 2) Bearings with curved track or bearings following a curved track or guide.

[0844] 3) Primary damper mass

[0845] 4) Secondary spring

[0846] 5) Secondary mass

[0847] 6) Secondary dashpot

[0848] Description: [0849] The embodiment contains two sub-structures: A mass supported by bearings (2,3) and a damped oscillator (4,5,6). [0850] The embodiment can damp vibrations in the horizontal plane. [0851] The frequencies f.sub.1 and f.sub.2 can be estimated by common theory or experimentally. [0852] The internal damping (ζ.sub.2) can be determined experimentally. [0853] As the primary damper mass moves horizontally, the curved track forces the damper masses upwards contributing to a change in potential energy, i.e. the restoring force (stiffness) is gravity based.

[0854] FIG. 46 shows a schematic cross-sectional view of a dashpot 100 used as a part of the second damping element in an embodiment of the damper according to the invention. The dashpot 100 is intended for use in an upright position in order to damp vibrations in an essentially vertical direction such as typical vibrations occurring in floors, walkways, bridges or buildings. The dashpot 100 shown in FIG. 46 and discussed below can be used in any of the above embodiments having a dashpot.

[0855] The dashpot 100 comprises a cylinder 110 which is at least partly filled with a viscous liquid 120, e.g. a silicone oil, said cylinder 110 being attached to said first damping body 3. The dashpot 100 furthermore comprises a piston 130 having a piston body 140 which is submerged in said viscous liquid 120 and a piston rod 150 connected to said piston body 140, said piston rod 150 being attached to the second damping body 5. An outer diameter of said piston body 140 is smaller than an inner diameter of said cylinder 110. The dashpot 100 is furthermore provided with a piston ring 160 having an outer diameter larger than said outer diameter of said piston body 140 and smaller than said inner diameter of said cylinder 110, said piston ring 160 being mounted to said piston body 140 such as to be movable in a plane perpendicular to said piston rod 150. The piston body 140 comprises a piston body main part 140a and a piston body cover part 140b which, in the embodiment shown in FIG. 46, are attached to each other such as to slidably hold said piston ring 160 between them. To this end, as can be seen in the figure, the piston body main part 140a has a recess which slidably receives the piston ring 160. The piston body main part 140a and the piston body cover part 140b can be rotated with respect to each other as will be described further below and can then be locked by means of one or more screws not shown in the figure. Alternatively the piston body main part 140a and the piston body cover part 140b could also be integral.

[0856] The design of the dashpot 100 of this embodiment achieves the following effects: Relative movements between the first damping body 3 and the second damping body 5 are damped by the piston body 140 moving up and down and displacing the viscous liquid 120 as is known e.g. from dashpots used in vehicles. However, contrary to vehicles or other applications, the first damping body and the second damping body are only mounted on site at the structure. Consequently, small misalignments between the cylinder 110 and the piston body 140 cannot be avoided. If the outer diameter of the piston body 140 and the inner diameter of the cylinder 110 were essentially identical, then such small misalignments would lead to considerable friction between the piston body 140 and the cylinder 110. As a consequence, certain small amplitude vibrations would be too small to cause a displacement of the piston body 140 relative to the cylinder 110 and would therefore not be damped.

[0857] In order to avoid this lack of damping for small amplitude vibrations the outer diameter of the piston body 140 is smaller than the inner diameter of the cylinder 110, so that they can largely be prevented from getting in contact with each other. However, due to the difference in diameter between the piston body 140 and the cylinder 110 a flow path is provided in between whose characteristics, e.g. width, would depend on the specific misalignment rendering the required precise adjustment of the second damping element difficult. In order to allow for a precise adjustment of the second damping element, the piston ring 160 is provided such as to be movable in a plane perpendicular to said piston rod 150, i.e. the horizontal plane in FIG. 46. Irrespective of the specific misalignment between the cylinder 110 and the piston body 140 the loosely fitting piston ring 160 defines a predetermined flow path width available for the viscous liquid flowing between the cylinder 110 and the piston body 140. In other words, the horizontally slidable piston ring 160 absorbs horizontal misalignments between the cylinder 110 and the piston body 140.

[0858] In addition to the flow path whose width is determined by the outer diameter of the piston ring 160 and the inner diameter of the cylinder 110, additional flow paths may be provided by bores or slots through the piston body 140. Two such bores are indicated by dashed lines in FIG. 46. Damping can be adjusted by fully or partially blocking bores by means of screws. Alternatively, in the embodiment shown in FIG. 46, the piston body main part 140a and the piston body cover part 140b may both be provided with slots having a predetermined width in the angular direction, i.e. in the horizontal plane. Rotating the piston body main part 140a and the piston body cover part 140b relative to each other allows to vary the overlap of the respective slots and thus the flow path available through the piston body 140 between a flow path of essentially zero width and a flowpath having a predetermined maximum width in order to adjust the damping characteristics of the second damping element.

[0859] In practical implementations for damping vertical vibrations in a building a dashpot 100 with the following dimensions has successfully been used:

Cylinder inner radius: 68 mm
Piston ring outer radius: 67 mm
Piston ring inner radius: 57 mm
Piston ring thickness: 6 mm
Total piston thickness: 14 mm
Total cylinder height ca. 200 mm
Total dashpot height ca. 300 mm

[0860] In the embodiment of FIG. 46 the cylinder 110 is attached to the first damping body 3 whereas the piston rod 150 is attached to the second damping body 5. However, it is also possible to choose an inverse arrangement in which the cylinder 110 is attached to the second damping body 5 whereas the piston rod 150 is attached to the first damping body 3.

[0861] In FIG. 46 an embodiment is shown in which the dashpot 100 is part of the second damping element arranged between the first damping body and the second damping body. As an alternative or in addition to such an arrangement, it is also possible to provide such a dashpot 100 as part of the first damping element arranged between the first damping body and the structure. In this case the cylinder 110 can be attached to the structure whereas the piston rod 150 is attached to the first damping body, or, alternatively, the cylinder 110 can be attached to the first damping body whereas the piston rod 150 is attached to the structure.

[0862] The dashpot 100 shown in FIG. 46 and described above can be used in any of the preceding embodiments in which the first and/or the second damping element comprises a dashpot.

REFERENCES

[0863] [1] Maurer & Söhne, Schwingungstilger und Viskodämpfer, February 2001, available at https://web.archive.org/web/20160304134217/http://www.maurer.eu/fileadmin/medien/05_downloads/Prospekte/DE/BSS/Prosp_MAURER_Schwingungstilger Viskosedaempfer_de.pdf [0864] [2] L. Tophøj, N. Grathwol & S. O. Hansen (2018), Effective Mass of Tuned Mass Dampers, MDPI Vibration 1, 1, pp. 192-206. [0865] [3] Lei Zuo, Effective and Robust Vibration Control Using Series Multiple Tuned-Mass Dampers, J. Vibration and Acoustics 131, ASME, (2009). [0866] [4] Korenev & Reznikov (1993), Dynamic Vibration Absorbers, Wiley & Sons. [0867] [5] Toshihiko Asami (2017), Optimal Design of Double-Mass Dynamic Vibration Absorbers Arranged in Series or in Parallel, J. Vibration and Acoustics 139, ASME [0868] [6] G. B. Warburton (1982), Optimum Absorber Parameters for Various Combinations of Response and Excitation Parameters, Earthq. eng. struct. dyn. 10, pp. 381-401. [0869] [7] Jerome J. Connor (2002), Introduction to Structural Motion Control, 1st. ed., Prentice Hall.