Study on the curing process of scarf-repaired composite laminates

The curing process of scarf-repaired composite laminates under a hot bonder is systematically investigated. Temperature responses in the repair zone, heating blanket, auxiliary material layers, and parent plate were experimentally obtained at different heating rates. A three-dimensional heat transfer finite element model incorporating auxiliary material layers was developed, and the temperature fields, degree of cure, and residual stress evolution in the repair patch and adhesive film were simulated and analyzed by integrating curing reaction kinetics and CHILE model. The results show that the experimental and finite element simulated temperature histories agree well, with a maximum deviation of no more than 3℃. Increasing the heating rate shortens the curing cycle and reduces thermal disturbance to the parent plate but intensifies exothermic reactions within the patch, leading to severe temperature overshoot and localized heat generation. The adhesive film region exhibits a relatively stable thermal response without noticeable overshoot due to its distinct material properties and bonding to the parent laminate. Furthermore, a predictable linear relationship exists between the heating rates of the heating blanket and the repair zone. These findings reveal the thermo-chemo-mechanical behavior of scarf-repaired composite laminates during curing under a hot bonder and provide a basis for optimizing repair process parameters.