Implementation and stability analysis of the QMITC-TLH elasto-plastic finite strain (2D) element formulation

In several articles that were published in the last few years, it was discu ssed the fact that some new four-node elements, based on the enhanced and m ixed strain techniques, even though are stable for infinitesimal strain ana lyses, develop spurious zero energy modes under some finite strain deformat ion patterns. Hence, we find of strong interest to re-analyze our QMITC-TLH four-node element, previously formulated for elasto-plastic finite strain analyses. In this paper, we discuss some implementation details of the elem ent and we show, for specific finite strain deformation patterns, that the element formulation is free from spurious zero energy modes. (C) 2000 Elsev ier Science Ltd. All rights reserved.