On non‐parametric fatigue optimization

The present work presents a novel approach for semi-analytic adjoint sensitivity-based design optimization nonproportional fatigue damage. In order to apply damage in optimizations, an essential part is calculate correct sensitivities. However, this not straight forward since calculation typically include rainflow counting and critical plane search algorithms. Therefore, no derivatives are directly available the calculation, only functional values given by numerical computation. existing literature considered simplified until closed-form differentiability satisfied. these simplifications applicable industrial examples where accurate life estimates required. differentiation of with respect stress tensor applied semi-analytical sensitivities at material points multiple load cases. proposed method verified demonstrated using different parameter types including analysis. Additionally, academic compared stiffness optimized designs. designs show improved results both specific when comparing Furthermore, it successfully variables (sizing, non-parametric shape bead) as well formulations either objective or constraint.