A Novel and Practical Approach for Determination of the Acoustic Nonlinearity Parameter Using a Pulse-Echo Method

Measurements of the acoustic nonlinearity parameter beta are frequently made for early detection of damage in various materials. The practical implementation of the measurement technique has been limited to the through-transmission setup for determining the nonlinearity parameter of the second harmonic wave. In this work, a feasibility study is performed to assess the possibility of using pulse-echo methods in determining the nonlinearity parameter beta of solids with a stress-free boundary. The multi-Gaussian beam model is developed based on the quasilinear theory of the KZK equation. Simulation results and discussion are presented for the reflected beam fields of the fundamental and second harmonic waves, the uncorrected beta behavior and the properties of total correction that incorporate reflection, attenuation and diffraction effects.