Optimization analysis of local reinforcement plate forming for B-pillar of plain woven carbonfiber fabrics based on VFABRIC

Plain woven carbon fiber fabric offer significant potential for the lightweight design of automotive body parts; however, it also introduce challenges in the molding process, particularly in controlling molding defects. To address these challenges, this study investigates the molding defect characteristics of plain woven carbon fiber fabric through experimental and numerical simulations, proposing a multi-objective optimization method to improve fabric formability. First, the mechanical properties of plain woven carbon fiber fabric was evaluated using the picture frame shear test, and the key factors influencing it formability was identified. Second, using the B-pillar local reinforcement plate as a case study, the effects of blank holding force magnitude, as well as the length and width of the blank holding region, on the fabric's formability were examined. Additionally, the distribution patterns of the shear angle and fiber-directional strain under blank holding conditions were analyzed. Finally, a multi-objective optimization method based on the NSGA-II algorithm was developed to enhance fabric formability. The results demonstrate that as the shear angle increases, the wrinkling strain along the fiber direction rises significantly. Through optimization, the maximum axial angle and fiber strain were reduced by 85.5% and 99.3%, respectively, significantly minimizing molding defects in the B-pillar local reinforcement plate and improving the component’s formability.