Simultaneous optimization of topology and bi-material distribution of three-dimensional structures for addressing local heat accumulation in layer-upon-layer additive manufacturing process

This paper introduces a novel approach based on a topology optimization (TO) model to efficiently distribute material phases for minimizing structural compliance and enhance local heat evacuation in additive manufacturing (AM). The approach simultaneously optimizes the structure for its intended function and behavior during layer-by-layer production. While AM allows intricate, topologically optimal multi-material designs, it often induces high temperatures and heat fluxes, risking part failure and compromising mechanical properties. To address this, a 3D gradient-based bi-material and functionally graded TO method is presented, considering total volume percentage and a thermal constraint based on temperatures of local sub-domains. The methodology involves density-based multi-material TO, interpolating elastic moduli, thermal conductivity, and heat flux based on proposed extensions of solid isotropic material with penalization method. Subsequently, a steady state analysis is performed in each sub-domain whose top element layer is exposed to a heat flux, simulating AM process. Both 2D and 3D numerical results demonstrate the contribution of the presented approach in preventing localized heating-induced geometrical patterns in AM. Additionally, the proposed method proves effective in producing superior designs without the need for sacrificial support structures in bi-material and functionally graded material designs, offering self-supported structures.