原位聚合碳纤维增强聚甲基丙烯酸甲酯基复合材料损伤与修复研究

基于热塑性复合材料易修复的特性，开展了碳纤维增强聚甲基丙烯酸甲酯(PMMA)基复合材料修复技术研究。研究了工艺温度、压力和时间对复合材料力学性能的影响规律。结果表明：在200℃、0.75 MPa压力下保持10 min可以获得优化的复合材料力学性能。引入低速冲击损伤，使用热压修复工艺修复碳纤维增强PMMA基复合材料的损伤。通过X射线断层扫描测试、超声波无损检测技术和断面摄像方法评估了此复合材料的损伤行为和修复效果。结果表明：低速冲击对碳纤维增强PMMA基复合材料的损伤分为低变形量区域的纵向开裂与分层和高变形量区域的纤维断裂与基体失效的混合模式。碳纤维增强PMMA基复合材料损伤试样经过热压修复后，损伤外形恢复良好，损伤区域大小显著减少，内部的开裂和分层等损伤恢复良好，复合材料压缩强度从140 MPa恢复至263 MPa，达到未损伤复合材料压缩性能(307 MPa)的85.7%。

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).