Using data-driven thermal analyses, the effects of various characteristics on the effective thermal conductivity of 3D composite structures are investigated. The characteristics considered include the thermal and geometric properties of the composite constituents, i.e., the thermal conductivity of phases, aspect ratio and volume fraction of particles, the interface thermal resistance, and the presence of percolation paths in the composite structures[1].

In this study, a random generator and finite element mesh was employed to generate sharp-interface composite structures, which were then relaxed into a diffuse-interface microstructure using the Allen-Cahn equation. Computational thermal homogenization was implemented to determine the effective thermal conductivity of the sample, and voxel-wise microstructure analysis was conducted to identify the percolation path. Additionally, local thermal fluxes were visualized along the percolation path. Finally, a data-driven-based sensitivity analysis (SA) was used to analyze the contributions of various characteristics on the corresponding effective thermal conductivity of samples. Moreover, two surrogate models were generated, one to map the relationship between the characteristics and the thermal conductivity, and the other to classify the microstructures in terms of having percolation path [2,3,4].

SA shows that the particle volume fraction, followed by the interface thermal resistance, is the most influential parameter determining the effective thermal conductivity of the analyzed microstructures. Moreover, the two trained surrogate models could successfully map the relationship between the characteristics and the thermal conductivity of the composite structures and classify the microstructures based on the presence of percolation path.

References
[1] M. Fathidoost, Materials & Design, 2023, accepted.
[2] Y. Yang, Scripta Materialia, 2022, 212, 114537.
[3] B. Lin, Materials & Design, 2021, 197, 109193.
[4] F. Kargar, ACS Applied Materials & Interfaces, 2018, 10, 37555–37565