No abstract

In this article, a non-contact laser Doppler strain sensor designed for fatigue testing with the resonance-testing machine is presented. The compact sensor measures in-plane displacements simultaneously from two adjacent points using the principle of in-plane, laser-Doppler vibrometry. The strain is computed from the relative displacements divided by the distance between these two points. The optical design, the mathematical model for estimating noise-limited resolution, the simulation results of this model, and the first measurement results are presented. The comparison of the measurement results of our sensor with the results of a conventional strain gauge shows that our design meets the measurement requirements. The maximum strain deviation compared to conventional strain gauges of the laser-Doppler extensometer is below 4×10−5 in all performed experiments.

A system was developed to evaluate the physiological effects of whole body vibration and noise on rats. The system design consists of a closed loop feedback method of ensuring the vibration generated matches the experimental parameters for vibration. Preliminary experimentation will verify that mechanical properties of the platform table will not alter the intended magnitude and frequency of vibration. This system holds promise for future studies for whole body vibration and noise research.