A scaling method to enhance detection of a nonlinear elastic response

The signature of nonlinearity in the elastic response of a specimen to an impingent ultrasonic wave is usually determined through Fourier analysis, which provides low amplitude signals, often below noise level. We suggest here an alternative, based on the amplitude dependence of the response of the system. Our procedure is conceptually simple and easy to implement. In addition, it keeps simultaneously into account the nonlinear signature effects on phases, amplitudes, and frequencies of the response. The sensitivity of the approach to the presence of nonlinearity is proven experimentally.