Abstract Wire-and-Arc Additive Manufacturing (WAAM) has been recently adopted to create innovative structural forms and architectural shapes. As shown by few experimental investigations, the layer-by-layer deposition induces a remarkable anisotropy in the elastic response of the WAAM-produced alloys. A suitable topology optimization technique is implemented to account for this peculiar behavior of the material, which is generally disregarded in design tools that are conceived for traditional manufacturing. First, an orthotropic material model is derived from the data of an experimental investigation that was recently performed on alloys made with 308LSi stainless steel wire feed. Then, an optimization procedure is implemented that exploits, as design variables, not only the density field of an orthotropic material phase, but also the orientation of the symmetry axes of such material with respect to a reference frame (i.e. the printing direction used to build the whole structural element). Minimum weight problems with displacement constraints are solved to find optimal solutions that are compared to those achieved by performing topology optimization with (i) isotropic stainless steel or with (ii) the WAAM-produced alloy for prescribed orientations. Numerical simulations assess that the printing direction remarkably affects the stiffness of the optimal layouts, as well as their topology.

中文翻译：

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线弧增材制造结构元件的拓扑结构和构建方向的同时设计

摘要 最近采用线弧增材制造 (WAAM) 来创建创新的结构形式和建筑形状。很少有实验研究表明，逐层沉积在 WAAM 生产的合金的弹性响应中引起了显着的各向异性。实施了一种合适的拓扑优化技术来解决材料的这种特殊行为，这在为传统制造而设计的设计工具中通常被忽略。首先，正交各向异性材料模型源自最近对用 308LSi 不锈钢送丝制成的合金进行的实验研究的数据。然后，实施优化程序，利用作为设计变量的不仅是正交各向异性材料相的密度场，以及这种材料的对称轴相对于参考系的方向（即用于构建整个结构元件的印刷方向）。解决具有位移约束的最小重量问题以找到与通过使用 (i) 各向同性不锈钢或 (ii) WAAM 生产的合金进行拓扑优化所获得的最优解相比较的最优解。数值模拟评估打印方向显着影响最佳布局的刚度，以及它们的拓扑结构。解决具有位移约束的最小重量问题以找到最佳解决方案，与通过使用 (i) 各向同性不锈钢或 (ii) WAAM 生产的合金为指定方向执行拓扑优化所获得的解决方案进行比较。数值模拟评估打印方向显着影响最佳布局的刚度，以及它们的拓扑结构。解决具有位移约束的最小重量问题以找到与通过使用 (i) 各向同性不锈钢或 (ii) WAAM 生产的合金进行拓扑优化所获得的最优解相比较的最优解。数值模拟评估打印方向显着影响最佳布局的刚度，以及它们的拓扑结构。