Experimental investigation of harmonic generation at solid-solid contacting surfaces by obliquely incident ultrasonic wave

Abstract

The higher harmonic generation characteristics at contacting surfaces subjected to an obliquely incident ultrasonic wave is studied experimentally. To this purpose, a 10-cycle, 1-MHz longitudinal burst wave is sent to the contacting interface of aluminum blocks with the incident angle 45°. The amplitudes of the fundamental and the second-harmonic components are evaluated quantitatively by calibrating the voltage amplitudes obtained by the piezoelectric transducer against a laser-Doppler vibrometer. The results are compared to those for the normal incidence. The influence of the contact pressure and the surface roughness on the harmonic generation behavior is examined.