COUPLED STRUCTURAL THERMAL ANALYSIS OF THE DEFECT FORMATION PROCESS DURING CFRP TAPE LAYUP

The Automated Fiber Placement (AFP) is the technology for automated layup of multiple narrow prepreg tapes in CFRP (Carbon Fiber Reinforced Plastics) manufacturing of structural components for aircraft. Because most AFP devices cut the material perpendicular to the feed direction, geometrically complex layup can result in localized gaps and overlaps that can affect the mechanical properties of the molded product. The bending modulus of prepreg tapes is the dominant factor for defect formation in the layup process. For the layup using CFRTP (Carbon Fiber Reinforced Thermoplastics) tapes, the material is heated during the tape layup and thus the temperature variation and distribution during forming have a large effect on the bending modulus of prepreg tapes [1]. In this study, we modeled the laminate with internal defects made by the AFP process, and we performed a coupled structural thermal analysis for the gap elimination when the out-of-plane pressure was applied, considering the temperature-dependent material properties of CFRTP. We showed a relationship between the bending stiffness of the layer above the gap and defect formation in CFRTP.