Improved Method for Determining Interfacial Stresses in Composites

The conventional finite element method shows its weakness in determining the stress distributions along fiber matrix interfaces. This is because the chosen element displacement functions do not explicitly and/or implicitly satisfy the equilibrium and compatibility conditions that prevail at the interfaces. A procedure has been proposed to modify the conventional finite element method so as to allow the elastic stresses along the fiber matrix interfaces of two‐ and three‐dimensional fiber‐reinforced composites to be determined with improved accuracy. The results obtained by this modified method for a two‐dimensional problem are compared with both a photoelastic and a traditional finite elelment solution. The comparison shows that the modified solution is in better agreement with the photoelastic test data than the traditional solution. The results obtained by the modified method for a three‐dimensional problem are compared with a traditional finite element solution and the modified method is found to be superior.