PSI - Issue 80

Stanislav Buklovskyi et al. / Procedia Structural Integrity 80 (2026) 146–156 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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3.3. Finite Element analysis of RVEs To determine the overall thermal conductivity of the composite, the prescribed temperature gradient was applied to the RVE, and the resulting heat flux was determined by finite element simulations. The conductivities were extracted as proportionality coefficients between the determined heat flux and the applied temperature gradient. The RVEs of the CB/UHMWPE nanocomposite were discretized using the open-source Iso2mesh meshing software (Fang & Boas, 2009). The mesh, consisting of four-node tetrahedral elements with reduced integration was exported for numerical simulations in the commercial finite element package Hexagon Marc (Marc element type #135). Each RVE contained approximately 100,000 elements for the CB-containing layers and 900,000 elements for the UHMWPE granules. Three loadcases were applied to each RVE, as presented in Table 2. In the Table, 1+ , 1− , 2+ , 2− , 3+ , 3− are the faces of the cubic volume element with outward normals for the corresponding coordinate axes, 1 , 2 , 3 are the applied temperatures in 1 , 2 , 3 directions, correspondingly. TABLE 2. Load cases to determine the effective thermal conductivity parameters of the composite. Loadcase 1 (thermal gradient in 1 direction): 1− : 1 =293 ; 1+ : 1 =393 2+ , 2− , 3+ , 3− : Loadcase 2 (thermal gradient in 2 direction): 2− : 2 =293 ; 2+ : 2 =393 1+ , 1− , 3+ , 3− : Loadcase 3 (thermal gradient in 3 direction): 3− : 3 =293 ; 3+ : 3 =393 1+ , 1− , 2+ , 2− : A custom MATLAB-based data processing script was used to compute the effective thermal conductivity of the composite from the FEA results. The workflow included extraction of heat flux value at the integration points of finite elements, retrieval of nodal coordinates to calculate individual element volumes, and computation of volume averaged heat flux in each principal direction. The average heat flux in the i -th direction ̅ was calculated as the volume average of heat fluxes for each element: ̅ = 1 ∑ ( ) ( ) , = 1,2,3. =1 (4)