碳纤维复合材料胶铆接头静态拉伸和循环拉伸失效行为

Failure Behavior of Rivet-Bonding CFRP/CFRP Joints in Static Tension and Cyclic Tension

摘要:

对碳纤维复合材料（CFRP）的胶接、铆接、胶铆混合接头进行静态拉伸和循环拉伸疲劳实验，对3类接头的连接强度及失效行为进行分析，预测该接头达到10⁶循环次数时的载荷水平。对胶铆接头中胶接和铆接的贡献进行讨论，分析拉-拉疲劳失效过程中CFRP层合板、胶层、铆钉的相互作用。对3类接头在静态拉伸和循环拉伸下的失效机制进行了总结，提出3种改善铆接强度的方案。结果表明：胶接对胶铆混合接头强度起决定性作用，铆接对接头起到“二次保护”的作用；所研究的CFRP胶铆混合接头，在80%、65%、55%、45%静态最大载荷水平下的疲劳寿命分别为8 174、22 568、95 014、331 916次。在37.1%的载荷水平下该接头的拉-拉疲劳寿命可达10⁶次； 铆钉孔的开裂是CFRP铆接及胶铆混合接头的主要失效形式，在铆出侧增加垫片与在铆钉孔表面涂敷结构胶2种方法可提高铆接强度30%左右。

Abstract:

Experiments of static tension and cycle tension-tension fatigue are performed for the carbon fiber reinforced plastics （CFRP） bonding， riveting， and rivet-bonding joints. The strength and deformation behavior of the three types of joints are analyzed， the load when the joint reaches infinite cycle life is predicted， the contribution of bonding and riveting to the rivet-bonding joints is discussed， the interaction of laminate， adhesive layer， and rivet in the tensile failure process of CFRP riveted joint is analyzed， the failure mechanisms of the three types of joints under static tension and tension-tension fatigue are summarized， and three methods to improve the riveting strength are proposed. The results show that for the same CFRP laminate， it is the bonding that decides the rivet-bonding joint strength when the shear strength of adhesive is higher than that of rivet. Rivets play a role of “secondary protection” for the rivet-bonding joints. The median fatigue life of the investigated CFRP rivet-bonding joint at a static maximum load of 80%， 65%， 55%， and 45% is 8 174， 22 568， 95 014， and 331 916 times， respectively. At a load of 37.1%， the tensile fatigue life of the joint can reach 10⁶ times. Rivet hole cracking is the main failure modes of CFRP rivet and rivet-bonding joints. Adding gaskets on the riveting side and coating the surface of rivet holes can improve the riveting strength by about 30%.