A direct modification method for strains due to non-conforming modes

This paper addresses an efficient modification method that eliminates the undesirable effects of<br />strains due to various non-conforming modes so that the non-conforming element can pass the patch test<br />unconditionally. The scheme is incorporated in the element formulation to establish new types of non-conforming<br />hexahedral elements designated as NHx and NVHx for the regular element and variable node<br />element, respectively. Non-conforming displacement modes are selectively added to the ordinary<br />(conforming) element displacement assumptions to improve the bending behavior of the distorted solid<br />element. To verify the validation of proposed direct modification method and the improvement of element<br />behavior, several numerical tests are carried out. Test results show that the proposed method is effective<br />and its applications to non-conforming solid elements guarantee for the element to pass the patch test.