Bending of CFRTP Pipe Laminated with Unidirectional Cut-Fiber Sheets

Abstract

The local heat bending of CFRTP pipes fabricated by laminating unidirectional fiber sheets was investigated. In the sheet with an axial fiber direction, fibers were separated at the same length and width using a cutting plotter. Laminated sheets were heated and pressed with silicone rubber onto an inside wall of a steel pipe to fabricate a consolidated pipe. Local heat bending was carried out by bending with a tension tool. A CFRTP pipe of 31 mm diameter was bent to a 50 mm curvature radius at the inside corner. The coefficient of elongation of the outside corner was 0.6. The strength of the elongated cut-fiber sheet was investigated to maintain the strength of the bent pipe. The material structure and rigidity after the bending were examined. Improvements for the local heat bending of CFRTP pipes were summarized.