Thermal-mechanical coupling topology optimization of multi-phase infill structures with a non-gradient porosity optimization method

• Published in: International journal of heat and mass transfer Vol. 210; p. 124198
• Main Authors: Yang, Xuefei, Li, Hao, Gao, Liang
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.08.2023
• Subjects: Functional gradient structure; Multi-objective design; Porous structure; Thermal-mechanical coupling; Topology optimization; Multi-objective design; Topology optimization; Porous structure; Thermal-mechanical coupling; Functional gradient structure
• ISSN: 0017-9310; 1879-2189
• DOI: 10.1016/j.ijheatmasstransfer.2023.124198

•A full-scale topology optimization method of multi-phase infill structures is proposed.•The topology optimization considering thermal-mechanical coupling is studied.•A non-gradient porosity optimization method (NPOM) is proposed.•A robustness enhancement method for porous structures is proposed. Mechanical structures in the real world are often subject to different types of physics which affect their performance and reliability. Recent studies have revealed that porous structures can be an ideal solution for multiphysics problems due to their multifunctionality. In this paper, a full-scale topology optimization method of multi-phase infill structures, i.e. non-gradient porosity optimization method, is proposed to exploit the advantages of different phase materials and solve multiphysics problems efficiently. The method builds upon a unified multi-material density-based topology optimization framework to interpolate the thermal stress coefficient in order to characterize the dependence of the thermal stress load upon the design variables. To generate sparse but stable structures distributed in the interior of a given shape, the upper bound of the solid material volume fraction in the neighborhood of each element in the design domain is constrained. In particular, the influence radius of each element is considered as a separate variable to be optimized, which is calculated directly from field functions in finite element analysis (FEA) without additional sensitivity analysis. In the proposed method, the element pseudo-density and porosity are optimized simultaneously, which further expands the design space and improves the performance of infill structures. Subsequently, the improved weighting method is used to aggregate multiple objective functions. The whole analysis and optimization process are based on a full-scale FEA, thus avoiding scale separation and naturally ensuring the optimized spatial gradient infills to be connected smoothly. Numerical examples with different thermal and mechanical load conditions are presented to demonstrate the feasibility and effectiveness of the proposed method.