挖补修理复合材料层合结构湿热性能研究

针对挖补修理复合材料结构服役中的湿热问题，试验研究挖补用胶粘剂、胶粘剂与复合材料胶接界面的湿热性能，湿热条件下挖补层合板的拉伸、压缩、低速冲击、冲击后拉伸与压缩行为。在此基础上，建立理论分析模型，对挖补层合板的湿热内应力及其拉伸、压缩、低速冲击、冲击后力学性能进行分析。揭示常用挖补胶粘剂、胶粘剂与复合材料胶接界面湿热性能退化机理，以及挖补中斜接面应力分布不均匀对胶粘剂损伤机理与破坏行为的作用，研究挖补胶层湿热性能不均匀性对挖补复合材料结构性能的影响，建立湿热条件下挖补复合材料结构拉伸、压缩、低速冲击以及冲击后力学性能有效的分析方法。所有试件全部采用国产材料和航空飞行器结构常用层合结构，研究结果可为复合材料挖补修理材料与典型结构工程数据库提供可用的数据，为复合材料挖补修理提供具体的分析方法与设计参考，并可为复合材料挖补胶粘剂材料的评定与研制方向提供指导。

This project focuses on the hygrothermal effects on the properties of scarf-repaired composite laminates during the service period. The properties of the selected adhesive materials and the interface between adhesive and composite materials under hygrothermal environments are studied experimentally. The mechanical behavior under hot/wet environments of the scarf-repaired laminates subjected to different loads, including tension, compression, low velocity impact, and tension and compression after impact are studied experimentally. Based on these studies, theoretical models are established to analyze the hygrothermal inner stress and the mechanical properties under tension, compression, low velocity impact, tension and compression after impact of the scarf-repaired laminates under hygrothermal environments. The deterioration mechanism of the selected adhesives and the interface between adhesive and composite materials will be revealed. The influences of non-uniform stress distribution along the bond line on the failure mechanism and fracture behavior will also be studied. The effects of the non-uniform properties under hygrothermal environments on the properties of scarf-repaired composite laminates will be studied, and an effective analytical method will be developed to analyze the mechanical properties of the scarf-repaired composite laminates subjected to tensile and compressive loads before and after low velocity impact, as well as the mechanical behavior under low velocity impact. In this research, all the materials are domestic and the composite laminates are common structures used in flight vehicle. The research results can be meaningful in practical engineering application, such as providing useful experimental data for the engineering database of repaired materials for composite laminates and typical structures, providing detailed analytical methods and design references for composite structure repair，giving evaluation method for adhesive meterial properties and giving the direction of the future research on the adhesive materials used in composite scarf repair.