DYNAMIC INTERACTION BETWEEN RECTANGULAR PLATE AND MULTI-LAYERED POROELASTIC MEDIA

Abstract

This thesis is concerned with dynamic interaction between a rectangular plate and a multi-layered poroelastic medium. The plate is assumed to be massless and rigid, and subjected to time-harmonic vertical, horizontal, and moment loading. In addition, the contact area between the plate and the supporting medium is assumed to be fully permeable. The poroelastic medium under consideration consists of N poroelastic layers of different thicknesses and material properties, and each layer is governed by Biot’s poroelastodynamics theory. The interaction problem is formulated by dividing the contact area into a finite number of small rectangular elements with uniform traction distribution. Nodal points are selected at the center of each element. An equation system is formed to determine the magnitude of contact traction at the nodal points by imposing appropriate rigid body displacement boundary conditions. The influence functions required to establish the flexibility equation system correspond to the displacement of a multi-layered half-space under vertical and horizontal loads of unit intensity. These influence functions are obtained by employing the exact stiffness matrix method. A computer program based on the present numerical scheme has been developed, and the accuracy of the solution scheme has been confirmed by comparing with existing solutions. Selected numerical results are presented to demonstrate the influence of various parameters such as poroelastic material parameters, frequency of excitation, embedded depth, plate aspect ratio etc., on the compliances of a rigid rectangular plate.