Triangular finite elements with rotational degrees of freedom and enhancedstrain modes

Three sets of enhanced strain functions are considered for the improvement of the three-node triangular finite element with rotational degrees of free dom. In each case, four enhanced strain terms are used. The four unknowns a ssociated with the enhanced strain terms can be eliminated by static conden sation so that nine degrees of freedom remain for the enhanced elements. Fa ster convergence in the energy norm is achieved. The enhanced elements are also able to deal with nearly incompressible plane strain problems consider ed, provided all rotational degrees of freedom do not vanish at all element nodes. (C) 2000 Elsevier Science Ltd. All rights reserved.