An accurate low order plate bending element with thickness change and enhanced strains

A three-dimensional variational formulation is used to obtain a plate bendi ng element which includes the thickness change of the plate. The nodal degr ees of freedom for the four-node element are the deflection w, the rotation s theta (x) and theta (y), and the thickness change H. Bilinear functions o f the in-plane coordinates xi and eta are used for the approximation of the deflection, the rotations and the thickness change. Integration in thickne ss direction is performed analytically. One key feature of the element is t hat the three-dimensional constitutive equations for the six stresses hat e not to be modified. Using eight enhanced strain terms, a well performing p late bending element is obtained.