Local tensor radiation conditions for elastic waves

A local boundary condition is formulated, representing radiation of elastic waves from an arbitrary point source. The boundary condition takes the for m of a tensor relation between the stress at a point on an arbitrarily orie nted section and the velocity,and displacement vectors at the point. The te nsor relation generalizes the traditional normal incidence impedance condit ion by accounting for the angle between wave propagation and the surface no rmal and by including a generalized stiffness term due to spreading of the waves. The effectiveness of the local tensor radiation condition is demonst rated by detailed finite element time and frequency analysis of a concentra ted force in infinite three-dimensional space, and by a time analysis of a pulse load in a two-dimensional underground gallery. (C) 2001 Academic Pres s.