Cumulative second-harmonic generation of Lamb-mode propagation in a solid plate

This article describes the physical process of cumulative second-harmonic g eneration of Lamb-mode propagation in a solid plate. In general, cumulative second-harmonic generation of a dispersive guided wave propagation does no t occur. However, the present results show that the second harmonic of Lamb -mode propagation arising from the nonlinear interaction of partial bulk wa ves and the restriction of the two boundaries of the solid plate does have a cumulative effect once some conditions are satisfied. Through boundary an d initial conditions of excitation, the analytical expression of the cumula tive second harmonic of Lamb-mode propagation has been determined. Numerica l results reveal that the cumulative second-harmonic fields are symmetrical regardless of whether Lamb-mode propagation is symmetrical or antisymmetri cal, and that the cumulative second-harmonic field patterns of Lamb-mode pr opagation are associated with the position of excitation source. (C) 1999 A merican Institute of Physics. [S0021-8979(99)00506-X].