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以碳纤维增强复合材料(CFRP)补强的平面外纵向焊接接头为研究对象,对其进行疲劳性能试验。为了模拟初始损伤,在节点板两端焊趾处引入人工预制初始缺陷。分析了应力幅、单/双面粘贴和CFRP板弹性模量对试件疲劳性能的影响。试验过程中采用沙滩纹加载方式,得到了疲劳裂纹随着荷载循环次数的扩展情况。试验结果表明:试件沿着其中一条预制裂纹发生断裂破坏,另一条预制裂纹也有不同程度的扩展;普通弹性模量CFRP板补强试件发生黏结层内破坏,高弹性模量CFRP板补强试件发生CFRP板断裂破坏;采用粘贴CFRP补强方法能够有效提高焊接接头疲劳性能,其疲劳寿命延长至未补强的1.28~8.17倍;裂纹扩展速率明显减慢,在CFRP材料覆盖区域尤为明显。采用双面粘贴和高弹性模量CFRP材料可以取得更好的补强效果,试件疲劳寿命延长程度分别约为单面粘贴和普通弹性模量CFRP板补强试件的2倍和3倍。
The CFRP-reinforced planar out-of-plane welded joint was taken as the research object, and its fatigue property was tested. To simulate initial damage, artificial prefabricated initial defects were introduced at the weld toes on both ends of the gusset plate. The influence of stress amplitude, single / double-sided bonding and CFRP sheet elastic modulus on the fatigue properties of the specimens was analyzed. The beach pattern loading method was adopted in the experiment, and the fatigue crack growth with load cycles was obtained. The test results show that the specimen cracks along one of the prefabricated cracks and the other prefabricated crack expands to some extents. The CFRP board with normal modulus of elasticity is damaged in the adhesive layer and the CFRP board with high modulus of elasticity The fracture of the CFRP plate occurred in the test specimen. Adopting the CFRP reinforcement method can effectively improve the fatigue performance of the welded joint, and the fatigue life of the welded joint was extended to 1.28 ~ 8.17 times that of the unreinforced one. The crack growth rate obviously slowed down, especially in the CFRP material coverage area . The use of double-sided adhesive and high modulus CFRP material can achieve better reinforcing effect, and the fatigue life extension of specimens is about 2 times and 3 times that of CFRP board with one-side bonding and ordinary elastic modulus respectively.