Repair of Interfacial De-bonding in a Single Carbon Fiber/PP Model Composite by Means of Selective Direct Heating of Carbon Fiber Inside

Abstract

Our previous work demonstrated that selective induction heating of carbon fibers increases the flexural modulus of CFRTP(Carbon Fiber Reinforced Thermo-Plastics) injection-molded products, indicating that selective heating of carbon fibers offers the possibility of repairing interface debonding in CFRTP. In this study, it is demonstrated that selective heating of carbon fibers using a focused halogen lamp can repair interfacial debonding in a monofilament model composite consisting of carbon fiber monofilaments and a polypropylene resin matrix, without requiring external pressure. The stress distribution in the stress recovery region around the fiber end was monitored before and after heating using a micro-Raman spectrometer. The debonding region and shear strength of the rewelded interface were evaluated from the fiber stress profile. Varying the heating conditions revealed that the reweld interface strength recovered to full virgin strength when it was heated for a short period of time at high power. In contrast, the rewelded interface strength was found to decrease after a long period of heating at low power. The shear strength of the repaired interface was also found to vary with the embedding depth of the fibers.