SEDL / STP / STP617-EB / STP26951S

Evaluation of Composite Curing Stresses

Pagano, NJ
Materials research engineer, Air Force Materials Laboratory, Wright-Patterson Air Force Base, Ohio

Hahn, HT
University of Dayton Research Institute, Dayton, Ohio

Pages: 13    Published: Jan 1977

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Abstract

A recently developed approach to predict the initial stress field within a composite laminate after fabrication processing is examined in some detail. In this approach, the material response is assumed to be elastic with temperature-dependent properties. With the introduction of the concept of a stress-free temperature, it is shown that this position is defensible by use of deformation measurements on unsymmetric angle-ply units. Implications concerning the influence of the curing stress field on initial damage level (first-ply failure) are studied analytically. The predictions indicate a marked effect of curing stress in certain laminates. The consequences of combined moisture and thermal effects on initial damage level also are discussed.