Motivated by the mismatch between the mechanical performance calculated numerically in topologically optimized designs and that observed in the associated parts fabricated by additive manufacturing (AM) processes, we integrate material characteristics produced via AM processes into topology optimization at low computational cost, by introducing a density-based topology optimization formulation that designs coated structures composed of anisotropic materials. Literature reveals that microstructures and the resulting elastic properties of AM-fabricated parts are affected by local characteristics such as scan pattern and local part shape, which results in material anisotropy and heterogeneity. To account for properties of as-built additively manufactured parts, our formulation for design of coated structures produces anisotropic structures and accounts for heterogeneous material properties in local regions such as near the surface. The formulation takes the form of a multi-material volume-constrained compliance minimization problem and adopts a material interpolation scheme that accommodates material anisotropy and extracts the solid-void interface to enforce the coating. We present a range of examples in 2D and 3D to demonstrate the key ideas, in which a more general volume constraint setting is defined that allows the coated structure design method to accommodate multiple local or partial volume constraints, so as to facilitate flexibility of the volume constraint definition. Lastly, we prove by experimental validation that the integration of AM specific material characteristics in topology optimization generates more optimal designs for fabrication by AM.

中文翻译：

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将增材制造工艺引起的材料特性集成到拓扑优化中


由于拓扑优化设计中数值计算的机械性能与增材制造 （AM） 工艺制造的相关部件中观察到的机械性能不匹配，我们通过引入基于密度的拓扑优化公式来设计由各向异性材料组成的涂层结构，以较低的计算成本将通过增材制造工艺产生的材料特性集成到拓扑优化中。文献显示，增材制造零件的微观结构和由此产生的弹性特性受局部特性（如扫描模式和局部零件形状）的影响，从而导致材料各向异性和异质性。为了考虑完工增材制造零件的特性，我们的涂层结构设计公式产生了各向异性结构，并考虑了局部区域（如表面附近）的异质材料特性。该公式采用多材料体积约束柔度最小化问题的形式，并采用材料插值方案，该方案适应材料各向异性并提取固体-空隙界面以增强涂层。我们提供了一系列 2D 和 3D 示例来演示关键思想，其中定义了一个更通用的体积约束设置，允许涂层结构设计方法适应多个局部或部分体积约束，从而促进体积约束定义的灵活性。最后，我们通过实验验证证明，将增材制造特定材料特性集成到拓扑优化中可以为增材制造产生更优化的设计。