SEDL / STP / STP617-EB / STP26950S

A Perturbation Solution for Interlaminar Stresses In Bidirectional Laminates

Hsu, PW
Graduate student and associate professor, Virginia Polytechnic Institute and State University, Blacksburg, Va.

Herakovich, CT
Graduate student and associate professor, Virginia Polytechnic Institute and State University, Blacksburg, Va.

Pages: 21    Published: Jan 1977

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Abstract

This paper considers a thin, elastic, bidirectional, symmetric composite laminate subjected to a uniform axial strain. All interlaminar stresses are determined by a 0^th-order perturbation analysis of the governing equations. The method of solution considers the laminate to be composed of an interior region (removed from the free edge) and a boundary layer region. The interior region is analyzed by dropping terms related to powers of the thickness-to-width ratio h/b in the dimensionless elasticity equations. The boundary layer region is studied by introducing a stretching transformation to the governing equations. A uniform solution is then formed by satisfying Prandtl's matching principle of perturbation theory.

Results for a four-layer, bidirectional graphite-epoxy laminate are compared with existing finite difference results. It is shown that the perturbation analysis provides more insight into the stress distribution near the free edge.