A new shell element accounting for through-thickness deformation

A new 7-parameter shell model is presented for thick shell applications. The model accounts explicitly for the thickness change in the shell, as well as the normal stress and strain through the shell thickness. Large deformations are accounted for by using the second Piola-Kirchhoff stress and the Green-Lagrange strain tensors. An assumed transverse shear strain interpolation is used to avoid shear locking. Two new interpolation schemes for the shell director are developed to avoid thickness locking. These interpolations are implemented and their consistent linearization is derived. Guidelines are developed for neglecting some of the quadratic terms in the consistent stiffness matrix to minimize computational time. The thick shell element performance is tested to show that the higher order terms result in improved accuracy. It also demonstrates that for thin shells, there is no significant deterioration in accuracy, compared with traditional 5-parameter shell elements. (C) 2000 Elsevier Science S.A. All rights reserved.