Mitigating Wrinkles in Double-Curved Forming: A Numerical Study on Quasi-Isotropic Preforms with Separators

Double-curved composite components are widely used in aerospace and transportation due to their high specific strength and low wind drag. However, Wrinkling is a main defect induced during the double-curved forming of quasi-isotropic composite preforms. This study aims to numerically investigate the strategies for suppressing wrinkles during the double-curved forming process with the aid of separators. A quantitative assessment of wrinkles was achieved by point-cloud analysis. The simulation results reveal that the severity of wrinkle defects exhibits a strong correlation with separator thickness and fabric-tool friction coefficient, while showing little dependence on the fabric-fabric friction coefficient. The investigation also demonstrates that wrinkle formation is primarily attributed to the work of friction, rather than the frictional force itself. Finally, considering the balance between cost and forming quality, a separator thickness of 4 mm and a fabric-separator friction coefficient of 0.3 were identified as the optimal configuration.