Effect of Hat-top Folding Shape on Formability in Press Forming of Hat-shaped Member

A hat-shaped member was prepared by press-forming continuous-fiber carbon-fiber-reinforced thermoplastics (CFRTPs) by locally heating the area of bending deformation and the area of interlaminar slip between the inner and outer surfaces of the laminate to prevent fiber wrinkling. In this study, we examined whether preheating the hat top below the melting point and embossing it at the same time as press forming can prevent the buckling of the fibers that could not be removed previously. The effect of embossing on product strength was verified by three-point bending tests and numerical analysis. As a result, the forming of dimples or beads improved the gripping force, and drawing in the excess fibers prevented the wrinkling of inner R fibers. Strength tests showed that bead-formed sheets with a fiber direction of 45 deg had the same strength and stiffness as the sheet. Analysis results showed that the interlayer adhesion of the embossed area was reasonably good.