A hybrid-stress finite element approach for stress and vibration analysis in linear anisotropic elasticity

A hybrid-stress finite element method is developed for accurate stress and vibration analysis of problems in linear anisotropic elasticity. A modified form of the Hellinger-Reissner principle is formulated for dynamic analysis and an algorithm for the determination of the anisotropic elastic and compliance constants from experimental data is developed. These schemes have been implemented in a finite element program for static and dynamic analysis of linear anisotropic two-dimensional elasticity problems. Specific numerical examples are considered to verify the accuracy of the hybrid-stress approach and compare it with that of the standard displacement method, especially for highly anisotropic materials. It is that the hybrid-stress approach gives significantly better results than the displacement method. Preliminary work on extensions of this method to three-dimensional elasticity is discussed, and the stress shape functions necessary for this extension are included