Design optimization of lattice structures with stress constraints
Design optimization of lattice structures with stress constraints
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DOI：
10.1016/j.matdes.2021.110026
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发表时间：
2021-08-10
影响因子：
8.4
通讯作者：
Tamijani, Ali Y.
中科院分区：
文献类型：
--
作者：
Fernandes, Rossana R.;Tamijani, Ali Y.
本文提出了一个经过实验验证的框架，用于执行受应力约束的晶格结构的拓扑和取向（形态学）优化。采用数值均匀化方法得到了单元胞的有效刚度和屈服应力，并进行了实验验证。由于单晶的正交各向异性，采用改进的希尔屈服准则来描述晶格强度。通过宏观结构拓扑优化实现有效的正交各向异性，进一步提高晶格结构刚度。采用粗网格进行均匀化优化，并将优化设计投影到细网格上。这大大降低了计算成本。最后，对投影设计进行后处理，确保优化后的点阵结构制造的可行性。该框架测试了两种情况：l型支架和单刃缺口弯曲（SENB）问题。两种情况下基于顺应性和应力约束设计的比较表明，在实施应力约束时发生的最优材料分布的变化导致更高的屈服强度。采用增材制造了SENB晶格结构，并将优化设计的刚度和屈服强度与数值计算结果进行了比较。CO 2021作者。Elsevier Ltd.出版。这是一篇基于CC BY-NC-ND许可（http://creativecommons.org/licenses/by-nc-nd/4.0/）的开放获取文章。
This paper presents an experimentally validated framework used to perform topology and orientation (morphology) optimization of lattice structures subject to stress constraints. The effective stiffnesses and yield stresses of a unit cell are obtained using numerical homogenization and validated experimentally. Due to the orthotropic behavior of the unit cell, the modified Hill's yield criterion is used to describe the lattice strength. The effective orthotropic properties are implemented via macrostructure topology optimization to further improve the lattice structure stiffness. Homogenization-based optimization is performed using a coarse mesh and the optimized design is projected onto a fine mesh. This reduces the computational cost significantly. Finally, the projected design is post-processed to ensure the fabrication feasibility of the optimized lattice structure. The framework is tested for two cases: an L-shaped bracket and a single-edge notched bend (SENB) problem. A comparison of the compliance-based and stress-constrained designs used in the two cases demonstrates that the changes in the optimal material distribution that occur upon implementing the stress constraint result in higher yield strength. The SENB lattice structures are additively manufactured and the stiffnesses and yield strength of the optimized designs are compared to those obtained numerically. CO 2021 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).