Three-Dimensional Finite Element Stress Analysis of Laminated Plates Containing a Circular Hole.

Abstract : One of the modes of failure of laminaated plates is delamination which initiates at a free edge. Experimental results and theoretical stress analyses found in the literature point to the interlaminar normal stress as a governing factor for this mode of failure. In this report, the stress behavior around a circular hole in a laminated plate is investigated using a three-dimensional finite element stress analysis. Attention is focused on the interlaminar normal stress distribution around the edge of the circular hole. Graphite epoxy laminates were modeled. Two types of loadings were considered. One was a uniform stress applied distant to the hole. The other was a uniform temperature change to represent the thermal portion of the laminate fabrication process. Other laminates of the type (0/90)s, (90/0)s, (0/2+ - 45/0)s, and (+45/02/0)s were considered. In total, results for over thirty laminates are presented. Most of the results are in tabular form.