Development of embedded element technique for thermal conduction analysis of carbon fiber composites

The embedded element (EE) technique has been developed in mechanical analysis to overcome the difficulties, such as poor mesh quality or high computational cost, of conventional direct mesh (DM) in finite element modeling of complex geometry. In this paper, the application of EE technique was expanded to thermal conduction analysis, and two new simplified EE modes (EE-Surf and EE-Sgl) were presented for comparison. Meanwhile, the EE technique was combined with the representative volume element, and the issues due to the combination were well addressed. Unidirectional and plain woven composites were selected as the test models for verification of the EE technique. The predictions of the homogenized properties, heat flux patterns and heat flux profiles by the DM and EE methods were compared. The results show that the EE technique is in good agreement with the DM model. Furthermore, the proposed EE-Surf mode, which only constrains the surface nodes of reinforcement domains with the matrix nodes, produces comparable high accuracy and can save computational cost due to the much reduction of constraint equations, compared with the standard EE mode. In addition, the mesh sensitivity analysis was performed to investigate the convergence of the results.