TC11焊接接头髙周疲劳分形损伤模型

Study on high cycle fatigue fractal damage model of TC11 alloy welded joint

根据金属疲劳断口具有几何分形特征,将Chaboche高周疲劳损伤模型推广到分数维空间,建立了综合考虑断口细观特征的髙周疲劳分形损伤演化模型.针对TC11钛合金电子束焊接接头,以载荷控制的疲劳试验为基础研究其高周疲劳性能;采用扫描电镜法(SEM)对断口微观特征进行定量分析,计算得到了各级载荷下疲劳断口的分形维数;通过对试验数据拟合,得到了疲劳损伤演化模型中的相关材料参数,从而建立了TC11焊接接头各级载荷下的分形损伤演化方程.

Based on the fractal characteristic of the metal fatigue fracture surf ace,Chaboche＇s high-cycle fatigue（HCF） damage model was extended to fractional dimension space.An HCF fractal damage evolution model considering internal micr o damage mechanism was built up in the present paper.By the stress-controlled te st,HCF properties of TC11 alloy welded joint were measured;and fractal dimension of the fracture surface was calculated through its scan electron microscope（SE M） picture.The key parameters of damage evolution model mentioned above were obt ained through experimental data fitting,and fractal damage evolution equation of TC11 alloy welded joint under each loading level was found thereof.