Process-induced strain and distortion in curved composites. Part II: Parametric study and application

Process-induced shape distortion is generated in curved composite parts. In the accompanying paper, the authors developed a fiber-optic monitoring method and confirmed that chemical cure shrinkage induces through-thickness shear deformation, which is the key deformation affecting final shape. The present paper first investigated the effects of thickness, flange length, and shape on internal states and process-induced deformation. Shear deformation was suppressed as the part thickness decreased and the flange length increased, resulting in larger spring-in. The shape effect was evaluated by comparing L- and U-shaped components. Larger warpage and spring-in were generated in the U-shaped part, indiacting that deformation in a U-shaped part is not a simple superposition of two L-shaped parts. Finally, a curved ply drop-off structure was investigated as a practical example. Internal strain was uniform in parts of different thickness, whereas residual deformation was non-uniform in the longitudinal direction due to mechanical coupling between the two parts.