An Ultrasonic Mode Conversion Technique for Characterizing Prism-Shaped Material Samples - Experimental and Numerical Results

摘要

An ultrasonic apparatus based on a mode conversion technique is described. It involves the measurement of the velocity of both compressional and shear waves in prism shaped specimens with only one transducer. The shear waves are generated through mode conversion at the interface between water and the specimen under test. The optimum coupling of the transducer and the special arrangement of the specimen enable the evaluation of not only second order elastic constants, but third order elastic constants as well, since the specimen can be easily subjected to both compressive and hydrostatic pressure. Preliminary experimental results obtained using different isotropic materials and numerical simulations of wave propagation based on the elastodynamic finite integration technique (EFIT) are presented. The results reveal that the prism technique is a significant improvement compared to traditional goniometer and rotating plate techniques.