Application of the Transfer Function for Measuring Ultrasonic Wave Speed in Engineering Materials

Ultrasonic testing is used in determining mechanical properties such as modulus of elasticity, shear modulus, and Poisson’s ratio, in characterizing microstructures, and in detecting flaws. One application of ultrasound, known as acoustoelasticity, involves the measurement of ultrasonic wave speed in solid materials as a function of applied stress. Due to the high resolution that is required, a type of phase-slope analysis technique known as the transfer function technique is introduced as an alternative to the popular cross-correlation technique for measuring ultrasonic wave speed. Time delay results from software-simulated sinusoidal waveforms and measurements of the acoustoelastic response of aluminum 6061-T6 and stainless steel show that significant improvement in resolution and reduction in calculation time can be achieved by using the transfer function technique.