Designs résistant à la fatigue utilisant l'optimisation topologique avec contraintes de tension

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. Structures undergoing high-cycle fatigue can be described by the stress-based approach and then a stress-based topology optimization framework, which has received great interest since almost 20 years because of the innovative designs that can be achieved to answer strength requirements, can be used. Literature reports many good results for shape optimization [Mrzyglod & Zielinsky(2006)] whereas in the eld 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), Sv ard(2015)]. The good behaviour of the implementation of an advanced fatigue criterion, i.e. the multiaxial Dang Van criterion [Dang Van et al(1989)] is first investigated 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 behaviour of the optimized solution. In a second time, the fatigue resistance is introduced in the well-known microstructural design [Sigmund (2000)] also know as architectured material design which are now considered in mechanical engineering because of their manufacturability thanks to additive manufacturing processes. Ensuring the fatigue resistance of the cellular material will by extension ensure the structural integrity of the overall structure itself. The optimization is performed by using the MMA optimizer [Svanberg(1987)] whereas the singularity phenomenon of the stress constraints is circumvented by using the qp-relaxation [Bruggi(2008)]. 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