Fatigue life analysis of body in white consideration of dynamic effects

The reliability of the quasi-static fatigue life analysis based on the unit-load approach is limited in the areas if the body in white (BIW) in which natural vibrations abd resonance effects arise within the used load spectra.This is especially the case where components with high concentrated masses are attached to the BIW. Hence, the potencial of proper dimensioning of the mounted components as well as their connections based on virtual methods is limited. This phenomenon was inverstigated by experiments with a test specimen illustrating the basic principle. As a solution, an alternative method is presented in which the dynamic effects are taken into consideration by means of a modal approach. The procedure of this method is illustrated with an example from the practice of vehicle development.