Fatigue Life Prediction and Evaluation of the W300-1 Fastening Clip

Abstract:

To effectively evaluate and predict the fatigue life of the W300-1 fastening clip during service， a finite element model was established， by considering the elastic-plastic mechanical properties and nonlinear contact relations of the clip. The strain characteristics of the clip at different installation loads were analyzed， and the test results were verified based on digital image correlation （DIC） technology. The fatigue life of the clip was calculated by applying the fatigue load in combination with the strain-life curve based on the actual measurement wheel-rail force time-history curve of Beijing-Shanghai High Speed Railway. The influence of installation torque， fatigue cycle load amplitude and the matching relations between them （the stress ratio） on the fatigue life of the clip was analyzed. The results show that the lowest fatigue life is found at the heel of the clip， and plastic deformation occurs no matter in a state of slightly under-tightening installation， normal installation， or over-tightening installation. The fatigue life decreases with the increase of installation torque and fatigue load amplitude， but it is linearly proportional to the stress ratio at the dangerous point of the clip. Therefore， to ensure the actual service life of the clip， especially in high speed or serious corrugation lines， it is recommended that the installation torque of the clip should not exceed 300 N·m.

Key words:fastener clip;installation torque;fatigue load;stress ratio;fatigue life