Nonlinear deformation and collapse analyses by boundary element method.

摘要

Although BEM formulations for nonlinear analyses first appeared in the published literature over thirty years ago, its development into an effective analysis tool has been rather slow. This may have been due to the choice of its primary application area of metal plasticity using Von-Mises model. It is well known that Von-Mises model is a very mild nonlinear material model and particularly so if one adapts a linear strain hardening law. Published literature, although extensive, contains primarily demonstration examples of thick cylinder under internal pressure, plates with holes etc. which always are some of the easiest problems to solve.; During the preliminary stages of the present work, author examined a number of complex elastoplastic problems of sufficient interest to conclude that the existing developments need to be re-examined so that vastly more complicated models such as Mohr-Coulomb, Modified Cam-clay, Generalized Soil Plasticity models (all are highly nonlinear in nature than Von-Mises model) can be incorporated in a consistent manner.; In the current work, we incorporate all of these above nonlinear material models and develop BEM algorithms based on initial stress, viscoplastic as well as Newton-Raphson plastic algorithms and demonstrate their applicability and reliability for the analyses of a large class of problems of practical interest.