Multiaxial Fatigue Life Prediction Based on Critical Plane Method

Abstract

Axis are usually hollow or solid cylindrical members. According to different needs, complex geometric elements such as holes, grooves, splines and steps will be designed on the axis. These parts often lead to stress concentration and high local stress, and multiaxial fatigue will be caused by multi-direction stress or strain in the process of processing. Taking the spindle of a bearing ring inner grinder as the research object, the working mechanism of the inner grinder, the feeding mode of the spindle and the workpiece are analyzed. The fatigue life prediction model of the spindle is determined by the critical plane method, and the number of stress cycles and fatigue damage of the spindle under four technological processes are also determined. In view of the fact that the inner grinder of bearing rings will change the size of workpiece irregularly, the influence of bearing rings of different sizes on the fatigue life of the spindle is simulated and analyzed. The maximum stress cycle times of the spindle are calculated, and the scatter plot is drawn. Finally, the relationship curve and function relationship between the inner diameter of bearing rings and the fatigue life of the spindle are obtained by the least square curve fitting method combined with the MATLAB curve fitting toolbox.