The transition from moderately thick shells to thick shells of general shape by using finite element analysis

Two types of shell bending elements are presented for the analysis of both moderately thick and thick shells of general shape. The first is a 2-D curved trapezoidal finite element with eight nodes, and it is based on a formulation that includes thickness shear deformation and does not neglect z/Rz/R in comparison with unity. The second is a 3-D rectangular prism isoparametric finite element with 20 nodes based on 3-D elasticity theory. To demonstrate the accuracy of these finite elements, a number of examples ranging from moderately thick to thick shell applications are presented and discussed with respect to thickness-to-shell radius ratios. In each example, the transitions from moderately thick shells to thick shells are calculated and compared with each other.