This application relates to an apparatus and method for detecting a microcrack using orthogonality analysis of a mode shape vector and a principal plane in a resonance point. The apparatus may include a measurement unit comprising multiple sensors and configured to measure whether a crack exists at a measurement target, and an analysis unit configured to determine whether a crack exists, on the basis of measurement values of the respective sensors. The measurement unit includes a fixing jig configured to fix the measurement target, an excitation means configured to apply a predetermined impact to the measurement target, and multiple acceleration sensors attached at predetermined locations on the measurement target. The analysis unit may further calculate frequency responses of the measurement target to the impact applied by the excitation means, and determine whether a crack exists by analyzing the number of resonance points and independence of the resonance points.

This application relates to an apparatus and method for detecting a microcrack using orthogonality analysis of a mode shape vector and a principal plane in a resonance point. The apparatus may include a measurement unit comprising multiple sensors and configured to measure whether a crack exists at a measurement target, and an analysis unit configured to determine whether a crack exists, on the basis of measurement values of the respective sensors. The measurement unit includes a fixing jig configured to fix the measurement target, an excitation means configured to apply a predetermined impact to the measurement target, and multiple acceleration sensors attached at predetermined locations on the measurement target. The analysis unit may further calculate frequency responses of the measurement target to the impact applied by the excitation means, and determine whether a crack exists by analyzing the number of resonance points and independence of the resonance points.

Provided is a test apparatus for an actuator, which can easily switch whether to establish or undo the coupling between an actuator to be tested and a load part configured to apply load to the actuator. A test apparatus for an actuator includes a load part for outputting load to be applied to an actuator to be tested, first levers for swinging around a rotational shaft in connection with an output from the load part, an idler link coupled to the output from the actuator to be tested, a second lever coupled to the idler link in a swingable manner and for swinging around a rotational shaft that is arranged coaxially with the rotational shaft of the first levers, and a clutch mechanism for coupling together the first levers and the second lever and undoing the coupling.

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.

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.

A device for testing mixed-mode fatigue crack growth rate includes a plate-like specimen, and a first fixture mechanism for exerting stretch, shear and torsion actions on the specimen via a second fixture mechanism. The second fixture mechanism is used for clamping the specimen and enabling the specimen to generate a mixed-mode fatigue crack in cooperation with the first fixture mechanism. The device further comprises a fatigue crack measurement instrument for measuring and recording the length of mixed-mode fatigue crack generated on the specimen.

A device for testing mixed-mode fatigue crack growth rate includes a plate-like specimen, and a first fixture mechanism for exerting stretch, shear and torsion actions on the specimen via a second fixture mechanism. The second fixture mechanism is used for clamping the specimen and enabling the specimen to generate a mixed-mode fatigue crack in cooperation with the first fixture mechanism. The device further comprises a fatigue crack measurement instrument for measuring and recording the length of mixed-mode fatigue crack generated on the specimen.

A strain inspection device of a printed circuit board (PCB) which is easily cracked or damaged by external pressure (force) applied to the PCB while the PCB is being assembled, and an attaching method thereof. The strain inspection device of a printed circuit board (PCB) includes a fixing member; and a damage indicator fixed to the PCB by the fixing member, having a crack guide through hole, and cracked or damaged along a corner of the crack guide through hole due to deformation of the PCB.

A strain inspection device of a printed circuit board (PCB) which is easily cracked or damaged by external pressure (force) applied to the PCB while the PCB is being assembled, and an attaching method thereof. The strain inspection device of a printed circuit board (PCB) includes a fixing member; and a damage indicator fixed to the PCB by the fixing member, having a crack guide through hole, and cracked or damaged along a corner of the crack guide through hole due to deformation of the PCB.

The present technology provides an impact test device and method. The rotational speed of a rotary drum with a rubber sample attached on the outer surface is set to a desired rotational speed, the impact cycle for the surface of the rubber sample of the contact member by the repeat-impact mechanism is set to a desired cycle, the impact load by the contact member is set to a desired impact load by a weight member, a desired contact member is selected from among the plurality of contact members with different specifications, and the contact member is repeatedly made to collide with the surface of the rubber sample by rotating a vertical excitation roller and pivoting the arm portion in the vertical direction with a rotation shaft.