An improved constant membrane and bending stress shell element for explicit transient dynamics

This paper presents an improved constant stress shell element for explicit transient analysis. The new shell element is based on the popular Belytschko-Lin-Tsay shell which is the most commonly used shell element in explicit transient analysis today because of its superior efficiency. Although the Belytschko-Lin-Tsay shell is well known for its accuracy in the class of mean quadrature elements, it exhibits performance deficiencies when the initial geometry of the element is warped and when the element is subjected to warping distortions. The new shell presented here provides improved accuracy by considering warped geometry with discrete normals at the element nodal points. Physical stiffness in the warping mode is introduced to improve the element behavior for warping distortions. The improvements are achieved with only a moderate increase in computational cost, while still preserving the membrane and bending behavior of the Belytschko-Lin-Tsay shell.