Progressive Failure of Advanced Composite Laminates Using the Finite Element Method.

In the study of fiber-reinforced resin composites, the analysis of the progressive failure of a liminate with a stress concentration subjected to plane stress poses a very interesting but complex problem. This thesis approaches this problem by using the finite element method to examine the progressive failure of symmetrical laminates. A modified maximum strain failure theory is proposed and a finite element computer program developed that accounts for progressive failure. A computer analysis of several unnotched laminate tensile specimens, with lamina at various angles, was made and these results are compared with experimental data. Circular hole tensile specimens with 0 deg90 deg90 deg0 degs and 0 deg or - 45 deg90 degs lamina were also investigated, and the progressive failure through the finite element grid presented. The ultimate failure loads of the circular hole specimens are compared with experimental data. Material properties used were those for Thornel 3005208 Graphite-Epoxy. Although the results obtained cannot be considered conclusive for all cases, they do compare favorably with experimental data for the unnotched specimens. The ultimate failure loads of the hole specimens were somewhat higher than those obtained experimentally. Author