A co-rotational 8-node degenerated thin-walled element with assumed natural strain and enhanced assumed strain

In recent years, solid-shell elements with the absence of the rotational degrees of freedom have considerable attentions in analyzing thin structures. In this paper, the non-linear formulation of a co-rotational 8-node degenerated thin-walled element with no rotational degrees of freedom is presented to demonstrate the solutions of linear and geometrically non-linear analysis for plate and shell structures. The assumed natural strain (ANS) and enhanced assumed strain (EAS) are used to overcome various locking problems, while the co-rotational formulation is employed to remove rigid body rotations for solving geometrically non-linear problems. In addition, the element formulation here uses plane stress condition in order to fit to thin-walled and shell applications, and the global, local and natural coordinate systems are employed to conveniently model the thin-walled geometry. Several numerical examples are presented to demonstrate the performance of the present element and the results are in good agreement with the references.