本文用热点应力法对焊接“十”字型方管节点的疲劳性能进行了试验研究及有限元分析,提出了热点应变集中系数的参数方程式,并根据本文试验结果及国外同类节点的疲劳试验数据给出了疲劳设计S-N曲线。此外,本文还提出了用残余变形监测疲劳裂纹开始出现的概念,井验证了用15％应变幅减少来判断裂纹产生的可靠性。 In this paper, the fatigue properties of welded “10” square pipe joints are studied by experiments and finite element analysis by hot spot stress method. The parameter equations of the hot spot stress concentration coefficient are proposed, and based on the test results of this paper and the fatigue test data of foreign similar nodes. Fatigue design SN curves are given. In addition, this paper also proposes the concept of using residual deformation to monitor the appearance of fatigue cracks. The well verifies the reliability of crack generation by using 15% reduction in strain amplitude.