Control of laminated structures by the acoustic free vibration method

The basic physics of the acoustic method of free vibration during revealing of zones of distortion of joints between elements of multilayer structures with layers with a high attenuation rate of elastic vibrations and low elastic modulus are reviewed. The results of experimental surveys of the spectral structure of impulses in zones where there is an absence of adhesive connection of material layers in the samples of the parts applied in the airframes are given. It is shown that, at a known diameter of discontinuity (or its area) determined by the contouring method by changing the signal amplitude in the specified frequency range, the depth of its occurrence may be determined with certainty by the amplitude and frequency of the spectrum components.