Studio numerico e sperimentale sulla generazione degli ultrasuoni tramite sorgente laser puntiforme

An experimental and numerical study on the ultrasonic fields generated in metals by a point laser source has been done. Energy and profile of the beam, pulse duration, extent and shape of the irradiated area affect amplitude, frequency and directionality of the ultrasonic waves. The study has been developed for the thermoelastic regime, where the laser radiation with low energy density limits the amplitude of ultrasounds and therefore the sensitivity in detecting the defects in extended bodies. By controlling some parameters the signal-to-noise ratio can be increased. The experimental study has been conducted by varying the impact area, the distribution of the beam energy in the impact area and the receiving direction. The numerical analysis replicates the experimental acquisitions, extending the analysis to measurements that can not be handled in the laboratory. The results of this work may provide a guide for choosing the optimal configuration