The rear axle of a trailer is a safety critical unit, which is exposed to complex and irregular loads. As the appearance of critical points is highly depending on the loading, static FE-methods are not sufficient to calculate the expected damage. Additional challenges are the simultaneous consideration of the influence of the high initial pre-stress in the screws and the contact conditions within the axle connection..

Use simulation methods to identify potential critical points considering the irregular loads measured on a test track. Based on simulations, different designs of the axle developed by SCHMITZ CARGOBULL AG are compared to decide which model should be selected as a first prototype.

The axle is isolated from the remainder of the system by the principles of mechanics. For each section force, one unit load case is calculated by standard FE-methods. By a quasi-static superposition of these loads, the stress tensor time signals are calculated at all nodes. Using the method of "critical planes" and the local strain approach, the resulting fatigue life is estimated.

Even in early stages of the development process different designs can be compared and optimized with respect to durability. The necessity to build and test several prototypes is reduced. Instead, only the best version has to be built and tested.