Experimental and numerical analysis of passenger car tie rod push-out and fatigue performance

Tie rods, one of the most important mechanical connections of the steering system, are subjected to static, dynamic and bearing loads under operating conditions. In this study, the fatigue test and the finite element method were used to evaluate fatigue performance of tie rod. In addition to this, the results of the finite element analysis made by different parameters were compared with the test results and the most suitable finite element fatigue analysis method was determined. For this purpose, fatigue test were applied with different fatigue loads to tie rods. Fatigue test results of tie rods were determined to have a behavior called low cycle fatigue (LCF) and high cycle fatigue (HCF) with respect to different loads. The ε-N method for LCF and the S-N method for HCF were proved to be more successful with analyzes. Neuber and ESED regional ε approaches were applied in the ε-N method, and it was found that the ESED method gives better results than the test results in all analyzes. In addition, the push-out strengths of the steel outer tie rods produced with different rolling forces were statistically evaluated between each other and the optimum rolling force was found. Then, the most suitable rolling design was determined according to the push-out and outer tie rod functional test data of the aluminum outer tie rods produced with different rolling edge designs and end cap thicknesses. Keywords: Fatigue life prediction, push-out, edge rolling, tie rod, ball joint.