An efficient DKT rotation free shell element for springback simulation in sheet metal forming

This paper presents two simple and efficient DKT triangular shell elements for the springback simulation after the sheet forming process. The first is the DKT12 shell element resulting from the superposition of the CST membrane element and the DKT6 plate element. The second element is called DKTRF element (DKT rotation free element) involving its three neighboring elements and six corner nodes, with only three translations dof per node. The three rotations around the sides are expressed in terms of the 18 nodal translational dof. The present formulation is more general and accurate than existing rotation free elements, particularly in the case of deep shells. A static implicit algorithm using a simple updated Lagrangian formulation is adopted for the springback simulation. Some academic examples and benchmark tests show the accuracy and efficiency of these two shell elements.