A singular hybrid finite element analysis of boundary-layer stresses in composite laminates

A singular hybrid finite element method for studying boundary-layer stresses in composite laminates is presented. The laminate elasticity basis and the fundamental solution structure for the boundary-layer field are briefly reviewed first. Formulation of a singular composite-edge element is based on the recently developed boundary-layer theory and the variational principle of a modified hybrid functional. The singular hybrid element is used conveniently in conjunction with displacement-based conventional elements. Numerical solutions for the well-known Pipes-Pagano problem are presented for illustration. Comparisons of the present solution with the laminate elasticity solution and conventional finite element results are made to demonstrate the accuracy and efficiency of the present approach. Influences of eigenfunction truncation, size and aspect ratio of the singular hybrid element as well as mesh configuration are studied.