Provided is a repetitive moment generating device that can be used for a fatigue testing machine and allows for a change in an amplitude of a repetitive moment to be imparted on a test piece even during rotation of an eccentric weight. A repetitive moment generating device includes: eccentric weight members provided at shaft bodies in a state where the eccentric weight members intersect the rotatably held shaft bodies and in a state where the eccentric weight members are slidable in a direction that intersects the shaft bodies; sliders that are attached to the shaft bodies in a state where the sliders are slidable in a direction of shaft centers of the shaft bodies and in a state where the shaft bodies are able to idle; link mechanisms that convert sliding motion of the sliders in the directions of the shaft centers into sliding motion in a direction that intersects the shaft bodies and transmit the sliding motion to the eccentric weight members; handle that are operation means for causing the sliders to slide in the directions of the shaft centers of the shaft bodies; and the like.

A system for dynamically mitigating resonance in a transport refrigeration unit (TRU) during a mission, having: a TRU controller configured for operating a TRU engine during the mission according to an operational baseline, and while operating the TRU engine, contemporaneously performing steps including: obtaining a first set of data that comprises real time measurements from one or more accelerometers installed in the TRU; converting the real measurements to a second set of data that comprises real time shock and vibration data; processing the second set of data in a control loop to determine an updated operational baseline that avoids resonance detected in the first set of data; and operating the TRU engine according to the updated operational baseline.

An actuator comprising a linear electrical machine (LEM) having a stator with a stator bore and a translator axially movable within the stator bore and defining a magnetic circuit airgap therebetween, at least one fluid bearing journal formed on the translator, at least one fluid bearing providing a bearing gap adjacent the translator to allow the translator to move axially within the stator bore, a preload chamber for applying a preload force to the translator, wherein the preload chamber is defined by a side wall, a first end wall and a second end wall at least part of which is movable with the translator, and wherein the bearing gap and the magnetic circuit airgap are coaxial.

Using tachometer-from-vibration processing of component signals and appropriate configuration allows for the analysis of both the compressor turbine and the power turbine of a turboshaft, turboprop, or twin spindle turbofan engine. One smart vibration sensor is positioned on or near the turbo engine and detects vibration data for components of both the gas compressor turbine and power turbine without the need for direct measurements of tachometer data from both the compressor and power turbine. From this, condition indicators are determined for monitored components on the sensor and returned to an onboard control unit.

The invention relates to a method for dynamic load simulation, wherein loads are specified by target signals and applied to a test object by a parallel kinematic excitation unit via an end effector, including the following operations: measuring loads at a contact point (200), comparing the measured loads with the target signals (300), and determining target pressures (400) for individual actuators of the parallel kinematic excitation unit for applying the target signals by use of a control algorithm (F.sub.q,ref). This provides a method for dynamic load simulation that reduces the time and cost expenditure compared to previously known methods and at the same time enables hardware-in-the-loop simulations to be used.

There is disclosed a device for use in evaluating the integrity of soil behind a wall of an infrastructure. The device generally has a frame having a plurality of rests adapted to be received onto the wall during use; a hammer assembly having an actuator fixedly mounted to the frame and a hammer element having a head movably mounted to the frame, the actuator being actuatable to move the head to strike the wall while the plurality of rests hold the frame in a fixed position relative to the wall; and a sensor configured and adapted to sense vibrations of a portion of the wall resulting from the strike and to generate a vibration signal indicative thereof.

The present invention relates to a method of fatigue testing an elongate specimen, such as a wind turbine blade, comprising: calculating a service life damage sum at one or more locations on at least one respective first section of an elongate specimen, responsive to at least one strain time history associated with the specimen; determining a predicted test damage sum at the one or more locations for each of a plurality of predetermined test blocks separately applicable to the specimen; and selecting at least one test block associated with the plurality of predetermined test blocks based on a comparison of the predicted test damage sum with the service life damage sum for each of the one or more locations, wherein the selected at least one test block is applicable to the specimen to cause a test damage sum at each of the one or more locations that at least substantially matches the service life damage sum at each of the one or more locations.

A new vibration test-cell that allows a static load to be applied simultaneously with lateral vibration coupled with in-situ microscopy that allows for the ability to open a fatigue crack up to a desired gap, as well as generate acoustic emission (AE) from vibration excitation, micro-fracture events are captured by the AE measurement while the physical observation of the crack faying surfaces is performed in-situ with an optical microscope embedded in the test cell.

A vibration test jig may include an upper jig frame to which a vibration test object is fixed and a lower base frame mounted to an oscillator, and a plurality of double parallelograms connected between the jig frame and the base frame, for generating displacements in an upward/downward direction and/or a forward/rearward direction. Each of the double parallelograms may include a complex four-articulation link structure and a wire rope isolator. The vibration test jig can simulate a deformation mode due to generation of resonances.

A device and a method for determining a microvibration effect on a millisecond-level space optical sensor are provided. The device includes: a light source, a star simulator, an air flotation vibration isolation platform, a suspension system/air flotation system, a zero stiffness system, a supporting system, a six-degree-of-freedom microvibration simulator, a signal driving apparatus, and a data acquisition and processing system. In the device for determining a microvibration effect on a space pointing measurement apparatus, a free boundary condition and a zero gravity environment are simulated by using a suspension system and a zero stiffness system. A light source and a star simulator simulate a star at infinity. A six-degree-of-freedom microvibration simulator simulates an on-orbit microvibration mechanical environment which is used as an input of a test. Extremely high-precision sensors collect system response data.