A cable tension calculation method simultaneously considering the sag, inclination angle and bending stiffness includes: querying basic parameters of a stay cable according to design data and construction data; considering influences of the sag, the inclination angle θ and the bending stiffness EI, to calculate dimensionless parameters γ, ε and λ.sup.2; testing an acceleration response of the stay cable by an acceleration sensor, to identify a frequency ω of the acceleration response of the stay cable, further calculating a dimensionless frequency {circumflex over (ω)} of the stay cable and the dimensionless parameters γ, ε and λ.sup.2, and substituting the dimensionless frequency {circumflex over (ω)} of the stay cable into a vibration characteristic equation, to establish a function relation between the dimensionless frequency {circumflex over (ω)} and a cable tension H* of the stay cable; and solving a root of the vibration characteristic equation, and identifying the cable tension H* of the stay cable according to the root.

An apparatus for emulating a variety of string instruments with a variety of configurations in order to measure the resulting, actual tension of a string on that instrument. The tension may be measured in real-time.

A system for estimating tension in a post-tensioned rod is provided. The system includes an impact device for transversely-impacting a post-tensioned rod, an accelerometer configured to generate data indicative of a vibrational response in the post-tensioned rod, and a receiver communicatively coupled to the accelerometer. The receiver includes a display, at least one input device, a communication module, a processor, and one or more memory devices coupled to the processor. Instructions stored on the one or more memory devices, when executed by the processor, cause the processor to receiver the data indicative of a vibrational response in the post-tensioned rod, process the received data to determine a difference between a first and a second modal frequency corresponding to the vibrational response, and store the difference between a first and second modal frequency corresponding to the vibrational response. The receiver is configured to transmit the stored difference between a first and second modal frequency.

The present disclosure provides systems, methods, and apparatuses for estimating tension in post-tensioned rods, such as anchor rods that support structural steel to concrete. A method of estimating tension in a target post-tension rod may include selecting a plurality of post-tensioned rods and modeling tension for the plurality of post-tensioned rods as a function of frequency differences between a first and a second modal frequency and cantilever length of each rod. The method may further include measuring the length of a cantilever of the target post-tensioned rod, determining first and second modal frequencies of the target post-tensioned rod, and determining a frequency difference between the first and second modal frequencies. The method may further include estimating tension in the target post-tensioned rod based on at least the model.

The present disclosure provides systems, methods, and apparatuses for estimating tension in post-tensioned rods, such as anchor rods that support structural steel to concrete. A method of estimating tension in a target post-tension rod may include selecting a plurality of post-tensioned rods and modeling tension for the plurality of post-tensioned rods as a function of frequency differences between a first and a second modal frequency and cantilever length of each rod. The method may further include measuring the length of a cantilever of the target post-tensioned rod, determining first and second modal frequencies of the target post-tensioned rod, and determining a frequency difference between the first and second modal frequencies. The method may further include estimating tension in the target post-tensioned rod based on at least the model.

A system to analyze vibration data includes circuitry that receives the vibration data, which is generated by a sensor that senses vibration of an object. The circuitry also analyzes the vibration data based on stored predetermined vibration data, and determines a characteristic of the object based on the analysis.

A belt sensor system comprising a first IR sensor disposed adjacent to a belt to detect a belt surface proximity and to generate a first signal therefore, a second IR sensor disposed adjacent to a belt to detect a periodic signal from a second belt surface and to generate a second signal therefore, a signal processor operating on the first signal and second signal to calculate a dynamic belt tension, and displaying the dynamic belt tension on a GUI.

The present invention relates to a method for determining the compressive tensile force acting on a fuel cell stack due to at least one tensioning element. Thereby, the compressive tensile force is the overall tensile force compressing the fuel cell stack. This is determined according to the invention by means of acoustic measurements on vibratable sections of the tensioning elements. The subject matter of the invention also includes a data processing program for carrying out the method according to the invention along with the use of a smartphone for carrying out the method according to the invention.

Current hoist systems often use a manual crank system with a lever arm that ratchets a rotational drum to tension a conductor. This disclosure describes systems and techniques for creating and operating a hoist system when connected and applying tension to an energized or de-energized conductor. Additionally, the systems and techniques may be applied to lifting or tensioning electrical equipment or cables that may support the conductor infrastructure. A hoist system may use a locally driven motor to apply a desired tension to a conductor or cable and may be controlled by an operator located at or away from the hoist system itself.

The present invention relates to a method for determining the compressive tensile force acting on a fuel cell stack due to at least one tensioning element. Thereby, the compressive tensile force is the overall tensile force compressing the fuel cell stack. This is determined according to the invention by means of acoustic measurements on vibratable sections of the tensioning elements. The subject matter of the invention also includes a data processing program for carrying out the method according to the invention along with the use of a smartphone for carrying out the method according to the invention.