Nonhomogeneous interface stress analysis in composite media using a mixed finite element formulation
Abstract
The compatible finite element formulation often results in discontinuous stresses at the element boundaries. This violation of the local equilibrium becomes evident especially at the bimaterial interfaces. The present work deals with the development of a mixed finite element formulation based on the Hellinger-Reissner variational principle and its evaluation for the stress analysis of nonhomogeneous interfaces. In order to avoid unnecessary constraint on some stress components, as many super-elements as the number of regions with different materials are first constructed. These are then assembled after condensing the discontinuous stress degrees of freedom at the common interfaces. At the end prior to the solution, the kinematic boundary conditions are satisfied, whereas the stress boundary conditions are either enforced or left unknown in the analysis. The mixed method performs well for the stress computation at the interface of highly dissimilar materials. In the absence of more accurate methods, the stress predictions of the compatible finite element method for the softer side of a bimaterial interface appear to be generally more reliable than those for the harder side.
- Publication:
-
13th Canadian Congress of Applied Mechanics
- Pub Date:
- May 1991
- Bibcode:
- 1991ccam.proc..190S
- Keywords:
-
- Algorithms;
- Composite Materials;
- Finite Element Method;
- Solid-Solid Interfaces;
- Stress Analysis;
- Stress Distribution;
- Cantilever Beams;
- Discontinuity;
- Displacement;
- Structural Mechanics