Optimal block loads of dynamic load history for fatigue durability testing

Sammanfattning: During a vehicle’s life it is experiencing complex loading from both driving and road conditions. This accumulating of loading might be damaging to the vehicle, leading to possible material fatigue cracking, hence it is a major importance to take it into account. During the design phase the vehicle will be tested on a rig to check the durability and fatigue life. This is done on the system as a whole or at component level. But as it is difficult to reproduce the actual complex loading, a much simpler loading sequence is applied on the component(s) during these tests. The purpose of this master thesis is to use an optimization software called HEEDS, which is based on a mathematical model that is applied in the software, to identify a possible multi-level block sequence which would generate the same fatigue damage as the reference complex loading sequence. This work is fully performed in calculation software, without using actual physical testing. The selected component is a front suspension low control arm (LCA) for which life is checked at various locations. The objective is to have the relative error identified as a relative ratio.