No abstract

The features of the behavior of the photoacoustic signal depending on mechanical stresses near the hole in the plate made of aluminum alloy D16 are investigated. A new nonlinear photoacoustic effect was discovered, which consists in the appearance of a nonlinear component of the photoacoustic signal depending on mechanical stresses near the hole. This dependence is recorded in the signal at the modulation frequency of the laser radiation. A theoretical description of the discovered effect of sound generation by the thermoelastic mechanism in stressed metals is proposed basing on the consideration of the thermal effect of laser radiation on their electronic subsystem.