Plane hybrid stress element method for 3D hollow bodies of uniform thickness

A semi-analytical plane hybrid stress element method is developed from the 3D Hellinger–Reissner principle for hollow bodies of moderate thickness that possess symmetry of geometry, material properties, loading and constraint conditions to its middle plane. Exact elastic plane stress solution is extended to the assumed distribution of stress and displacement fields. Traction free conditions on the external and internal surfaces that are perpendicular to the axis passing through the thickness direction are satisfied precisely. The element possesses good convergence characteristics and its results can be compared well with the results of simple and complex engineering problems reported in the literature.