ON THE STABILITY OF MIXED FINITE-ELEMENTS IN LARGE-STRAIN ANALYSIS OFINCOMPRESSIBLE SOLIDS

Some mixed finite elements for large deformation analysis of incompres sible solids are studied. The elements are based on the displacement/p ressure and enhanced strain mixed formulations. Specifically, it is sh own that a quadrilateral 4-node element that satisfies the inf-sup con dition in linear analysis - and hence is an effective element in such conditions - fails in large strain analysis. The reasons for this elem ent behavior are explored. Some comparisons of element predictive capa bilities are given. (C) 1997 Elsevier Science B.V.