Using Fatigue Life Prediction to Increase Reliability of Automotive Structures 2003-01-0471
In today’s automotive industry, mechanical engineers are encouraged to develop lightweight vehicles to reduce the consumption of energy. At the same time, the service life and safety standards, which become m ore and more rigorous, must be fulfilled.
Numerical analysis of the component’s lifetime in an early stage of the development process can increase the reliability of automotive structures, and lead to shorter development periods and cost reductions due to a decrease in testing expenditures.
Most cracks in fatigue testing originate in notches, welds or spot-weld joints. The dimension of the notches, the design and the position of the weld seams, as well as the number and the location of the spot weld joints have a significant technical and economical impact. In order to achieve an optimum use of the material, an optimization of these critical areas has to be performed.
This can be done by postprocessing the stresses of a Finite Element Analysis (FEA) in FEMFAT, a software package which automatically takes the stress gradient in notches and the special properties of weld seams and spot weld joints as defined in the FE-model into account. Furthermore the user can consider different influences for the fatigue analysis, like surface roughness, temperature and mean stress.
This paper includes the theoretical background and procedure of the computational optimization and will show applications on automotive structures.