Analysis of manufacturing effects on fatigue failure of an automotive component using finite element methods

In this study, the fatigue life of an automotive suspension component was analysed using finite element methods with regard to stamping and welding effects. Because automotive suspension components are produced by forming and welding sheet metal, there are various effects on the final product, such as uneven thickness distribution, residual stresses and weld notches. Manufacturing effects may change the mechanical performance of the automotive components; therefore, it is desirable to consider these effects in the early design stage. Residual stresses due to work hardening and thermal deformation were investigated through process simulation. The redistribution and relaxation of residual stresses in a component were investigated in fatigue life analysis under a cyclic loading condition. Various equivalent relaxation curves were investigated and one was selected after comparisons with test results. The fatigue simulation results were compared to the test results; a good correlation between the two was achieved for the residual stress effects in terms of life cycles and failure locations. The simulation results also show that welding produces more detrimental effects than stamping with regard to the fatigue life of a component.