拱桥新型不锈钢吊杆疲劳试验和螺纹连接应力分析

Fatigue test of arch bridge stainless steel suspender and stress analysis of threaded connection

在MTS电液伺服疲劳试验机上进行了直径70mm的新型不锈钢吊杆在拉伸荷载作用下的疲劳试验,疲劳荷载上限为700kN,下限为430kN,在经历了1 546 609次循环后,吊杆从下部螺纹连接公接头第一承载齿的根部突然断裂。采用ANSYS软件,建立了新型不锈钢吊杆螺纹连接的二维轴对称模型,分析了各螺纹承载齿承担的荷载以及螺纹齿根在拉伸荷载作用下的应力集中系数,分析结果表明,应力集中系数最大值出现在螺纹连接公接头第一承载齿的根部。同时还分析了螺纹连接的最大应力,结果表明,螺纹连接头最大应力的位置与吊杆断裂面疲劳裂纹源的位置相吻合。

A fatigue test and a finite element analysis on an arch bridge stainless steel suspender with threaded connections were carried out.A suspender which had a diameter of 70mm was tested under axial tensile loads range from 430kN to 700kN.The suspender suddenly failed from the thread root of the first loaded tooth in the pin after 1 546 609 cycles.A two-dimensional axisymmetric modeling ignoring the helix angle of thread was established with finite element software ANSYS to perform a stress analysis of the threaded connection.The stress concentration factors（SCF） at the root of the teeth of pin were investigated under applied external loading.The conclusive results had been drawn from the analysis including load distribution on the threads and location and value of maximum SCF in the pin.The location and value of maximum stress were given.The results show that the location of fatigue crack source on the fracture surface is consistent with the location of maximum stress.