Nonlinear propagation of narrow-band Rayleigh waves excited by a comb transducer

Quantitative experiments have been performed to measure the harmonic genera tion of narrow-band Rayleigh waves in aluminum. Based on a comparison of se veral methods, the Sokolinskii comb transducer was selected as an excitatio n source. Results are presented for narrow-band Rayleigh waves (center freq uency 9.85 MHz) generated by the comb and detected with a path-stabilized M ichelson interferometer. The on-axis, out-of-plane displacement amplitude w as measured as a function of distance from the source. Maximum out-of-plane displacements greater than 7 nm were observed. An existing quasilinear the ory that included both diffraction and attenuation was used to interpret th e data. Values of the nonlinearity parameter beta(11) = 0.21-0.23 predicted displacements in good agreement with the data and were consistent with val ues for beta(11) calculated from literature values of the third-order elast ic moduli of aluminum. [S0001-4966(99)03510-9].