GNPs改性环氧3D编织复合材料导热特性研究

Study on Thermal Conductivity Coefficients of 3D Braided Composites Reinforced with Graphene Nanoplatelets

石墨烯纳米片(Graphene nanoplatelets,GNPs)改性3D编织复合材料将GNPs与编织物有机融合,有望协同提高材料导热特性。然而,3D编织复合材料内胞和表胞呈现出不同的导热特性,加之GNPs的协同改性作用,增加了材料导热特性研究难度。本文紧扣GNPs改性3D编织复合材料细观结构特征,以GNPs改性树脂等效热导率表征为基础,基于周期性温度边界条件,构建材料的多胞有限元热物理分析模型,详尽研究了GNPs含量、编织角和纤维体积分数等对各胞元热导率的影响规律。分析表明:随着GNPs含量增加,3D编织复合材料导热特性逐步提升。随着编织角增加,GNPs改性3D编织复合材料横向热导率迅速增加而纵向热导率下降;同时,GNPs改性3D编织复合材料热导率随纤维体积分数增加而提升。上述规律为GNPs改性3D编织复合材料导热性能设计提供了坚实的理论基础。

3D braided composites reinforced with graphene nanoplatelets(GNPs)contribute to improving the thermal conductivity coefficients of the composites.However,the microstructures of 3D braided composites are so complicated that the interior and surface unit cells have different thermal conductivity.Meanwhile,the synergistic reaction of GNPs further improves the challenge of predicting the thermal conductivity of the composites.This paper investigates the thermal conductivity of 3D braided composites reinforced with GNPs by finite element modeling based on multi⁃unit cell models.Firstly,the thermal conductivity of epoxy resin modified by GNPs is analyzed by 2D periodical unit cell models.Then a detailed multi⁃unit cell model is introduced to establish the finite element model for predicting the thermal conductivity.Meanwhile,the periodical thermal boundary conditions are also applied to the finite element models.Finally,the effectiveness of the multi⁃unit cell modeling is validated through two typical cases.The thermal conductivity for the interior,surface and integral unit cell models are analyzed,respectively.The results indicate the thermal conductivity of 3D braided composites is improved obviously with increasing GNPs mass fraction.With the braiding angle increasing,the transverse thermal conductivity of 3D braided composites gradually increases and the longitudinal thermal conductivity decreases almost linearly.Meanwhile,the thermal conductivity of the composites gradually increases with fiber volume fraction increasing.The results provide important theoretical basis for the design of the thermal conductivity of 3D braided composites reinforced with GNPs.