Experimental investigation on vibration characteristics in thermosonics detection test

In order to investigate the vibration characteristics of the object in the nondestructive test using thermosonics, the device for measuring vibration micro-displacement was built based on the laser displacement sensor and the ultrasonic excitation equipment. On this basis, the vibration displacement of the object was measured under the condition of ultrasonic loading with the frequency of 40 kHz and non-ultrasonic loading respectively. Then, the analysis on the frequency spectrum of vibration displacement obtained by the test was carried out. The obtained results show that there is fundamental frequency in the vibration spectrum of the object as well as the high-order harmonic frequencies, which confirms the existence of acoustic chaos in the thermosonics detection test. This work is of importance as it lays the foundation for the further investigation on the detection mechanism of thermosonics.