[en] Stress based topology optimization has received great interest since almost 20 years because of the innovative designs that can be achieved to answer strength requirements. Fatigue is an important mode of failure in mechanical engineering and accounting for it as soon as the early stage of design using topology optimization sounds primordial. Literature reports many good results for shape optimization [Mrzyglod & Zielinsky(2006)] whereas in the field of topology optimization several authors have shown that considering fatigue in an optimization framework leads to more relevant solutions where fluctuating loads are involved [Holmberg E.(2015), Collet et al(2016), Svärd(2015)].
In order to check the good behavior of the implementation, we first investigate the implementation of an advanced fatigue criterion, i.e. the multiaxial Dang Van criterion [Dang Van et al(1989)], in the framework of a density-based topology optimization problem. The choice of this fatigue criterion is justifed by its good applicability in automotive or aeronautic industry as well as its relevancy with respect to experimental results. We present the sensitivity analysis with stress constraints and present some classical benchmarks to illustrate the behavior of the optimized solution.
In a second time, we introduce the fatigue resistance in the well-known microstructural design [Sigmund (1999)]. The new additive manufacturing techniques allow to fabricate components exhibiting architectured materials. In this perspective, ensuring the fatigue resistance of the cellular material will by extension ensure the structural integrity of the overall structure itself.
Both types of optimization framework are evaluated in term of their numerical performances and are compared to classical results generated by a regular stress-based topology optimization. Finally, the results are 3D-printed to assess for their manufacturability.
