Papers by Keyword: Unidirectional Laminate

Abstract: In order to eliminate the bubbles during composites manufacturing, a special performance was designed. And the effects of the speed of the resin injection on bubble content were investigated. The results demonstrate that the speed of resin injection has distinct effects on the bubble content. When the speed of resin injection is slightly higher than the speed of capillary injection, the bubble content of the test pieces with latitudinal fiber bundles is more than the test pieces without latitudinal fiber bundles. But when the speed of the resin injection is slower than the speed of capillary injection, the bubble content of the test pieces with latitudinal fiber bundles is less than the test pieces without latitudinal fiber bundles. These results will provide a reference for the design of RTM process parameters.

Abstract: A macromechanics constitutive model to describe the anisotropic creep behavior of unidirectional composites under off-axis loading conditions is developed with a particular emphasis on accurate prediction of temporal creep softening due to stress variation. A viscoplasticity model that takes account of a combined isotropic and kinematic hardening is adopted as a base for this formulation, and the evolution equation of the kinematic hardening variable is elaborated to enhance the accuracy of prediction of the transient creep softening due to stress variation. Validity of the modified kinematic-hardening viscoplasticity model is evaluated by comparing with the experimental results on unidirectional T800H/3631 carbon/epoxy composites. It is demonstrated that the proposed model can adequately describe the off-axis creep behavior of the unidirectional CFRP laminate under constant and variable stress conditions.