新型机加工弹簧静压状态下的应力集中研究

RESEARCH ON STRESS CONCENTRATION UNDER STATIC PRESSURE OF A NEW MACHINED SPRING

新型机加工弹簧静态拉压时螺旋槽端部应力集中现象十分严重,对弹簧的强度和疲劳寿命有很大的影响。通过Ansys软件分析弹簧基本参数对应力集中的影响,确定机加工弹簧存在应力集中的理论判据;探究切向应力释放孔对压缩变形量和应力集中系数的影响;基于强度理论和曲梁弯曲理论推导了无应力集中下的最大等效应力计算公式。研究表明:中径在15 mm~35 mm之间的机加工弹簧,当螺旋槽宽度与螺距之比小于0.5时存在应力集中现象;螺旋槽端部开切向应力释放孔,控制其孔径接近对应矩形截面高度时可将应力集中基本消除;所推导公式计算的内圈等效应力值与仿真值误差不超过3%,为该弹簧后续的工程设计及应用提供了重要参考。

The stress concentration at the end of spiral groove is very serious during the static tension and compression of the new machined spring,which has a great influence on the strength and fatigue life of the spring.The influence of spring basic parameters on the stress concentration coefficient was analyzed by ANSYS software,and the theoretical criterion for the existence of stress concentration in machined springs is determined.The effects of tangential stress release hole on compression deformation and stress concentration coefficient were investigated;Based on the strength theory and bending theory of curved beam,the formula of maximum equivalent stress without stress concentration was deduced.The results show that when the ratio of the width of the spiral groove to the pitch is less than 0.5,stress concentration occurs in machined springs with the middle diameter between 15 mm ~ 35 mm.The stress concentration can be basically eliminated by cutting stress release hole at the end of spiral groove and controlling its size to be close to the height of rectangular section.The error between the equivalent stress value of the inner ring and the simulation value is less than 3%.It provides an important reference for the subsequent engineering design and application of the new spring.