Press Forming of Hat-shaped Member by Local Heating

A hat-shaped member was prepared by press forming continuous-fiber carbon-fiber-reinforced thermoplastics (CFRTP) 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. Three-point bending tests were conducted on the V-bend formed product without any interlaminar slip by locally heating the bending line and on the press-formed product. Numerical analysis was performed to estimate in-plane stresses and predict the location of defects. As a result, the shape accuracy of press forming was higher than that of V-bending forming, and the maximum load and energy absorption of the pressformed product with a fiber direction of 45 deg were more than 10 % higher than those of V-bending forming. Under these conditions, the stress peaks in the numerical analysis and the position at which the product buckled were the same, so the position at which buckling occurred could be approximately predicted by the results of numerical analysis. Since the defects have not yet been eliminated, a more detailed temperature control of the corners is required to further increase the amount of interlaminar slip by approximately 20 %.