Definition of simplified fatigue tests using numerical optimization

Abstract

“Virtual prototyping” has been established as an important part of the development process for technical components and technical systems. Fatigue simulation is a main discipline in virtual prototyping, but it is a quite complex field, especially for structures being exposed to time-varying multi-channel loads. Thus, at the end of the development process, the series approval for technical components is often based on extensive fatigue tests, particularly with regard to automotive chassis parts.Currently, test-based fatigue qualification gathers interest in other process phases, for instance• to assure fatigue safety just for non-series / prototype parts• to make quality checks during series parts production on the supplier’s site• to validate fatigue simulation methods just within the first phases of the development processMain requirements concerning these fatigue tests are a simplified test set-up (cost reduction) as well as a short test duration (time reduction). These requirements are interpretable as constraints of a kind of “fatigue test optimization”. Reproduction of the results of the “full” fatigue test is the main objective of this optimization task.Some meaningful aspects of fatigue test simplification being essential for “classic” (manual) optimization are clarified using the main structural part of a double wishbone wheel suspension exemplarily. A very new method of numerical optimization to be presented overcomes limits and restrictions of manual optimization. It’s software implementation promises efficient fatigue test optimization by providing high quality results.