A NOVEL-APPROACH FOR DEVISING HIGHER-ORDER HYBRID ELEMENTS

This paper presents an efficient way to devise higher-order hybrid ele ments by generalizing the admissible matrix formulation recently propo sed by the author. The assumed stress or strain is first decomposed in to the constant, lower- and higher-order modes. In the absence of any higher-order modes, the resulting hybrid element would be identical- t o the corresponding sub-integrated displacement element. By a natural and straightforward method of orthogonalizing the higher-order modes w ith respect to the constant and lower-order modes, the element stiffne ss can be partitioned into a lower- and a higher-order matrix. With fu rther refinements, the method devised can readily be applied to a numb er of higher-order hybrid elements with enhanced finite element consis tency and computational efficiency.