Diagnosis of Metal Plates with Defects Using Laser Vibrometer

The method of nonlinear laser scanning vibrometry is used for diagnostics of thin cylindrical resonators of polycrystalline aluminum alloy D16 with latent defects and residual stresses. Flexural Lamb waves are used for diagnosis. The dependence of the frequency of the resonator eigenmode on the amplitude of the flexural Lamb waves in it is detected (the effect of the fast dynamics); it indicates the presence of defects in the material of the resonator. Coordinates of defects were identified by vibromodulation technique in the resonator.