Elasto/Viscoplastic Boundary Element Approach

In this chapter a boundary element approach to deal with continuum problems involving viscous effects is presented. Basic concepts of time-dependent material behaviour, together with some rheological models used in geotechnical engineering, are introduced for one-dimensional cases. The Perzyna’s viscoplastic model is chosen to model viscoplastic behaviour. Based on this viscoplastic representation, the theory is extended to general continuum problems. The overlay concept borrowed from finite elements formulation (48,49) is also adopted here in order to model more complex time-dependent and plastic responses. As in finite elements, the technique can be also extended to solve problems with pure plastic behaviour. Finally, the applications presented in the last section of this chapter show the accuracy of the approach when it is used to model time-dependent behaviour or to simulate plastic responses with or without anisotropic effects.