Influence of Cure Shrinkage on Process-Induced Stress and Deformation in Thick Thermosetting Composites
Final rept. Jun 1989-Jul 1991
ARMY BALLISTIC RESEARCH LAB ABERDEEN PROVING GROUND MD
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The development of residual sum is strongly influenced by processing history. Residual stress can have a significant effect on the mechanics and performance of composite structures by inducing warpage or initiating matrix cracks and delaminations. A fundamental study of the complex relationship between processing of thermosetting composites and residual sum has ban conducted by the authors Bogetti and Gillespie 1989, 1990a, 1990b. A cure simulation analysis coupled to a laminated plate theory model was used to study the development of processing- included sum and deformation in thick-section thermosetting composite laminates. Constitutive models were proposed to describe material behavior chemical hardening and shrinkage during cure Thermal expansion and chemical cure shrinkage contribute to changes in material specific volume and represent important sources of internal loading included in the analysis. In this work we focus on the effects cure shrinkage has on residual sum and deformation development in thick section glasspolyester and graphiteepoxy composite laminates. Additionally, model predictions of cure dependent modulus and dimensionless laminate curvature of graphite epoxy cross-ply are presented and found to be in good agreement with previously published experimental data.