铺层方式和搭接长度对CFRP与铝合金胶接-自冲铆接复合接头性能的影响

Effect on layup method and lap length on performance of CFRP and aluminum alloy bonding-SPR composite joints

为研究T700碳纤维板与6061-T6铝合金板胶接-自冲铆接复合工艺接头的力学性能和失效机理,通过拉伸剪切试验分析了不同搭接长度和不同铺层方式对接头强度的影响,深入探讨了接头的连接质量以及连接损伤,并采用扫描电镜分析了层合板铆钉孔周围的失效断裂特征以表征CFRP层合板的损伤机理。试验结果表明:接头的极限失效载荷和能量吸收值随着搭接长度的增加而逐渐增加,搭接长度L在25~30 mm范围内趋于平稳。接头的失效模式随着搭接长度的增加有所改变,搭接长度L在15~20 mm范围时,纤维撕裂破坏和互锁结构破坏基本持平,搭接长度L≥25 mm时以互锁机构破坏失效为主。[0°/90°]_(8 s)铺层方式的接头的极限失效载荷和能量吸收值较高,且主要以锁紧结构破坏失效为主;[±45°]_(8s)和[0°/45°/90°/-45°]_(4 s)铺层方式的接头伴随着胶层失效、基体裂纹、纤维撕裂和铆钉脱落,使承载区遭到严重破坏而失效。

In order to research the mechanical performance and failure mechanisms of bonding-SPR composite process joints between carbon fiber board and 6061-T6 aluminum alloy board,and the influences of different lap lengths and different layup methods on the performance of joints were analyzed by the tensile shear test.Then,the connection quality and damage of joints were discussed in depth,and in order to characterize the damage mechanism of CFRP laminates,the failure fracture characteristics around rivet holes were analyzed by SEM.The results show that the ultimate failure load and energy absorption of joints increase with the increasing of lap length,and the lap length L tends to be stable in the range of 25~30 mm.The failure mode of joints changes with the increasing of lap length,and the fiber tearing and interlocking structure failures are about equal when the lap length is 15~20 mm.However,the interlocking mechanism failure is the main reason for the lap length L≥25 mm.Additionally,the failure load and energy absorption values of joints are higher for the[0°/90°]_(8 s),which is mainly dominated by the failure of locking structure.The joints of[±45°]_(8 s)and[0°/45°/90°/-45°]_(4 s)are damaged seriously due to adhesive layer failure,matrix crack,fiber tear and rivet shedding.