Non-contact estimation of equivalent mechanical properties using the transient vibration response induced by an acoustic radiation force

This study aimed to verify a non-contact method for estimating equivalent mechanical parameters using the transient vibration response induced by the step-functional acoustic radiation force of focused ultrasound. First, the vibration distribution of a silicone rubber plate excited by an acoustic radiation force was measured. The results revealed that the vibration-excited area was larger than the beam size and dependent on the characteristics of the material. The equivalent mass, mechanical compliance, and mechanical resistance were estimated based on the mode frequencies, time constants of vibration decay, and maximum velocity amplitudes obtained from the transient vibration response. The estimation showed qualitative agreement with the expected trends corresponding to changes in the thickness of the rubber plate. These findings suggest that our method is effective for estimating equivalent mechanical parameters of objects, although challenges remain regarding spatial resolution.