Damage and repair study of in-situ polymerized carbon fiber reinforced PMMA composites

According to the repairability of thermoplastic composites, the repair process of carbon fiber reinforced PMMA composites was studied. The effects of temperature, pressure, and time on the mechanical properties of the composites were compared. Results show that the optimal repaired properties of composites could be obtained at 200℃ and 0.75 MPa pressure for 10 minutes. By introducing low-speed impact damage, the damaged parts of the composites were repaired by a hot pressing process. The composite's damage behaviors and repair effect were investigated by nondestructive testing and cross-section photography. Experimental results show that the impact damage of carbon fiber reinforced PMMA composites can be divided into two types: Lengthways cracking and delamination in small deformation areas and the mixed-mode of fiber fracture and resin failure in big deformation areas. After repairing, the damaged shape and the internal delamination damages of the damaged samples are recovered well, the volume of the damaged area is significantly reduced, and the compressive strength of the composite is recovered from 140 MPa to 263 MPa, which is 85.7% of the undamaged composite (307 MPa).