SIMPLE TRIANGULAR CURVED SHELL ELEMENT FOR COLLAPSE ANALYSIS.

A simple triangular shell element which incorporates the effects of coupling between membrane and flexural behavior and avoids membrane locking is described. The element uses a discrete Kirchhoff bending formulation and a constant strain membrane element. For the purpose of permitting inextensional modes and thus avoiding membrane locking, a decomposition technique, which can also be viewed as a strain projection method, is used. The method is illustrated first for a beam element and then for a triangular shell element. Results are presented for a variety of linear static problems to illustrate its accuracy and some highly nonlinear problems to indicate its applicability to collapse analysis.