CONTROL OF SPURIOUS MECHANISMS FOR 20-NODE AND TRANSITION SUB-INTEGRATED HEXAHEDRAL ELEMENTS

In this paper, control of spurious mechanisms for sub-integrated 20-no de and transition hexahedral elements is devised by an assumed stress approach. The higher-order stress modes for stabilizing the sub-integr ated elements are identified by examining the spurious mechanisms. Wit h an admissible simplification of the flexibility matrix, row vectors of the leverage matrix can be used as stabilization vectors. Numerical examples for the stabilized 20-node element are presented. Accuracy o f the derived element is far better than the fully integrated displace ment elements. Meanwhile, the for-mer also consumes marginally less CP U time than the latter.