A prismatic solid-shell finite element based on a DKT approach with efficient calculation of through the thickness deformation

In this paper, a prismatic solid-shell is developed. The element is intended to the analysis of shells during forming process and consolidation stage. To correctly perform the simulation of this step, the proposed element provides an accurate calculation of stress/strain through the thickness. The bending stiffness of the element is based on the formulation of a DKT plate element which leads to good numerical efficiency. An additional degree of freedom at the center of the element, allows at the same time, the use of a complete 3D constitutive law, to avoid the thickness locking and a variation of the normal stress in the thickness which makes it possible to check the load boundary conditions on the upper and lower surfaces. This is very important for process simulation, and in particular for consolidation. A set of examples shows the good precision of the proposed element in many of the classical shell tests and its ability to calculate with accuracy the normal strain/stress in thickness.