CFRP布单侧加固非承重十字焊接接头应力强度因子分析

Stress intensity factors of non-load-carrying cruciform welded joints with CFRP single-sided repair

对单侧CFRP布加固含焊趾裂纹非承重十字焊接接头进行研究,分析裂纹尖端处应力强度因子KI随CFRP层数、初始裂纹长度、CFRP弹性模量和黏结剂弹性模量的变化。钢板中性轴位置随上述因素发生改变,引起次弯矩,使未加固侧裂纹尖端处KI发生变化。有限元分析结果表明:增加CFRP层数可以减小加固侧裂纹尖端处KI,但增大了未加固侧裂纹尖端处KI;增加初裂纹深度会较大程度地增大同侧裂纹尖端处KI,减小异侧裂纹尖端处KI;提高CFRP和黏结剂的弹性模量可以减小加固侧裂纹尖端处KI,增大未加固侧裂纹尖端处KI。为保证加固的效果,进行单侧CFRP加固时需要考虑两侧裂纹尖端处KI,确保两侧都满足要求。

In this paper,stress intensity factors( SIFs) of mode-I( KI) of non-load-carrying cruciform welded joints with defects were studied. These joints were repaired with CFRP sheets on single side. The performance of KIwith respect to the number of CFRP layers,the initial crack depths,the modulus of CFRP and the modulus of adhesive was investigated. It is noticed that the neutral axial of the plate is shifted due to the repair,and a secondary moment was produced. As a result,the KIof the unrepaired side is changed. The FEM results show that the increase of the number of CFRP layers can decrease the KIof the repaired side,and increase the KIof the unrepaired side. The increase of the length of initial crack depths can increase the KIof the side,but decrease the KIof the other side by a relatively large amount. The increase of the modulus of CFRP and adhesive can decrease the KIof the repaired side,and increase the KIof the unrepaired side. In order to guarantee the repair effect,the KIon both sides need to be considered when repairing the joints on one side,and make sure both sides satisfy the requirements.