The role of fiber bundle interaction forces in non-isothermal compression molding of thermoplastic composites

The non-isothermal flow during compression molding of thermoplastic-based c omposites having a planar, randomly oriented fiber structure has been inves tigated. Local interactions at the bundle-bundle level were measured and a constitutive equation was derived to describe the shear and squeeze flow of the composites. This equation contains only micro-mechanics-related variab les, and accounts for the temperature dependence of the interaction forces. The flow of the material under industrial processing conditions can thus b e related to the deformation mechanisms of the reinforcement structure at t he scale of the individual fibers. Good agreement was obtained between the predicted and experimentally observed rheological behavior of the composite s in both shear and squeeze flow. The use of this approach to analyze tile industrial molding of complex-shaped parts is discussed.