A study of axisymmetric solid of revolution elements based on the assumed-stress hybrid model

A series of axisymmetric solid-of-revolution elements with 4-nodes and quadrilateral cross section have been developed based on the assumed-stress hybrid model. A linear boundary displacement assumption is employed for each element and a variety of interior stress assumptions have been made. Example problems of a thick cylinder under internal pressure and a thick sphere under internal pressure are utilized to evaluate the various elements, and several desirable stress assumptions have been identified. For the thick sphere problem, which involves a singularity problem as a result of the placing of an element at the axis of symmetry, several special treatments are suggested. Comparisons of present results with those obtained by the use of a 4-node element based on the assumed displacement model indicate that the present hybrid elements are far superior in predicting the stress distribution within the elements.