Forced vertical vibration of a rigid circular disc on a semi-infinite elastic solid

Introduction . The effect of a vibrating point force on the surface of a semi-infinite elastic solid was investigated in a classic paper by Lamb ((8)). When the point force is replaced by a vibrating rigid disc the problem is more complicated, because the displacement is specified under the disc and the remainder of the surface is stress-free. This gives rise to a mixed boundary-value problem.