Grating Shearography and its Application to Residual Stresses Evaluation
Grating shearography is a modification of moiré interferometry where a shearing element in the observation setup allows to directly measure strains, local rotations and out of plane slopes, with the extra advantage of insensitivity to parasitic vibrations. The theory is presented and the technique is applied to the problem of residual stresses evaluation using the incremental hole-drilling technique in an aluminium shot-peened sample. The strain sensivity, measured as the noise standard deviation, has been found to be 50 microstrains. The spatial resolution, measured as the shear distance, was 0.1 mm.
KeywordsResidual Stress Michelson Interferometer Noise Standard Deviation Sensitivity Vector Moire Interferometry
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