Triangular composite finite elements

Composite triangles consisting of four three-node triangles originally prop osed by Camacho and Ortiz are studied. It is shown that the original elemen t does not satisfy the Babuska-Brezzi condition nor pass the patch test. Re medies for these shortcomings are described. It is shown that the resulting elements are very robust for large deformation problems. In addition, comp osite triangular elements generated from four-node quadrilaterals are brief ly examined; their accuracy is found to be not as good as the composite tri angles. Copyright (C) 2000 John Wiley & Sons, Ltd.