Formability in Warm Deep Drawing of CFRTP Using Tensile Test with Crossing Angle of Carbon Fiber as a Variable

For warm drawing of twilled CFRTP(Carbon Fiber Reinforced Thermo Plastic), it is necessary to better predict wrinkling during deformation or bending and unbending at the corner of die and punch. Therefore, it is proposed to use a material model based on the change of crossing angle of twilled carbon fibers (in the following, the angle between the warp and the weft is called the crossing angle). In order to clarify the effect of this crossing angle, we prepared test pieces with different crossing angles by warm shear deformation, and measured the deformation resistance against loads in the direction in which the deformation progressed as well as in the reverse direction by tensile tests. From the experimental results, it was found that the increment of the deformation resistance when the deformation direction is reversed differs depending on the crossing angle. It was also clarified that the increment of the deformation resistance in the reversing direction becomes a larger value as the rocking angle, which is the limit crossing angle for deformation, is approached.