Singular stress distributions at circular holes in composite laminates
Abstract
Assuming the existence of a singularity in the stress distribution at a hole in a composite plate, the numerical determination of the strength of such a singularity using the finite element method with mesh refinement is reported. A finite element program using 20node quadratic solid isoparametric elements was written to investigate the stresses in a rectangular composite plate with a circular hole in its center. Using this program, a graphite epoxy composite and other laminates were evaluated for the strength of the stress singularity in the vicinity of a circular hole. The resulting values were very similar to those obtained analytically for singularities near a straight edge. This leads to the conclusion that the free edge singularity is the same whether the edge is straight or circular. This result opens the possibility of using singular finite elements for an accurate and efficient determination of the free edge stresses in laminates with straight or curved edges.
 Publication:

Twelfth Canadian Congress of Applied Mechanics
 Pub Date:
 May 1989
 Bibcode:
 1989apme.proc..308L
 Keywords:

 Composite Materials;
 Edges;
 Finite Element Method;
 Geometry;
 Perforated Plates;
 Rectangular Plates;
 Singularity (Mathematics);
 Stress Distribution;
 Computer Programs;
 GraphiteEpoxy Composites;
 Hole Geometry (Mechanics);
 Laminates;
 Structural Mechanics