Nonlinear Stoneley and Scholte waves

Spectral evolution equations are derived for plane, progressive,finite-ampl itude Stoneley and Scholte waves chat propagate along plane interfaces form ed by two semi-infinite, isotropic media in contact. The evolution equation s have mathematical forms identical to those obtained previously for Raylei gh waves [E. A. Zabolotskaya, J. Acoust. Sec. Am. 91, 2569-2575 (1992)], an d they are expressed explicitly in terms of the second and third-order elas tic constants of the media. Calculations were performed to simulate nonline ar surface wave propagation in several pairs of real media. Harmonic genera tion and shock formation associated with the Stoneley and Scholte modes are compared with the corresponding processes in Rayleigh waves. Waveform dist ortion is shown to be very similar for the three types of surface waves whe n the propagation distance is normalized by an appropriate shock formation distance. (C) 1999 Acoustical Society of America. [S0001-4966(99)02507-2].