Fully C-1-conforming subdivision elements for finite deformation thin-shell analysis

We have extended the subdivision shell elements of Cirak et al. [18] to the finite-deformation range. The assumed finite-deformation kinematics allows for finite membrane and thickness stretching, as well as for large deflect ions and bending strains. The interpolation of the undeformed and deformed surfaces of the shell is accomplished through the use of subdivision surfac es. The resulting 'subdivision elements' are strictly C-1-conforming, conta in three nodes and one single quadrature point per element, and carry displ acements at the nodes only. The versatility and good performance of the sub division elements is demonstrated with the aid of a number of test cases, i ncluding the stretching of a tension strip; the inflation of a spherical sh ell under internal pressure; the bending and inflation of a circular plate under the action of uniform pressure: and the inflation of square and circu lar airbags. In particular, the airbag solutions, while exhibiting intricat e folding patterns, appear to converge in certain salient features of the s olution, which attests to the robustness of the method. Copyright (C) 2001 John Wiley & Sons, Ltd.