Finite-life fatigue constrained topology optimization for self-supporting structures in additive manufacturing

This paper presents a topology optimization method for designing self-supporting structures by incorporating finite-life fatigue constraints under proportional loading conditions and overhang constraints specific to additive manufacturing. To ensure smooth boundaries for overhang angle descriptions, the material layout is modeled using B-spline parameterization. The loading history is analyzed using the rainflow counting method, which accounts for varying mean and amplitude stresses in accumulated fatigue damage based on the modified Goodman criterion and Palmgren-Miner's rule. The fatigue damage across the finite element model is scaled and aggregated to establish the fatigue life constraint, enabling the simultaneous optimization of both the build direction and structural topology. The effectiveness of the proposed method is validated through 2D and 3D case studies.