Linear and quadratic Serendipity hybrid-stress elements are examined in respect of stability, coordinate invariance, and optimality. A formulation based upon symmetry group theory successfully addresses these issues in undistorted geometries and is fully detailed for plane elements. The resulting least-order stable invariant stress polynomials can be applied as astute approximations in distorted cases through a variety of tensor components and variational principles. A distortion sensitivity study for two and three-dimensional elements provides favourable numerical comparisons with the assumed displacement method.
|Number of pages||26|
|Journal||Computer Methods in Applied Mechanics and Engineering|
|State||Published - Dec 1984|