Effect of Residual Stresses on Fatigue Strength on the Smooth and Splined Parts of Spring Torsion Bars

The article discusses the effect of residual stresses on fatigue strength torsion bars by using Dang Van criterion, at stress concentration root tooth and smooth part bar. Residual compressive were induced surface during technological processes cold rolling torsional pre-strain (pre-setting) to plastic range, increase elastic linear range reduce state loading. Normally, reduction in bar mounting point is provided increased diameter splined part, compared In case a small difference between parts bar, crack can be initiated notch, which causes break operation after few hundred loading cycles. FEM analysis was performed article. actual measured non-destructive X-ray method place with notch Van’s failure criterion used determine behavior Therefore, paper, three methods combined optimum lifetime exposed required cyclic torque. results showed that are useful up certain limit where retarded initiation occurred, but further caused an maximum shear stresses, which, turn, before achieving number