纤维方向对环氧树脂/玻纤复合材料导热性能影响

Effects of Fibre Orientation on Thermal Conductivity of Epoxy/Glass Fibre Composites

为研究环氧树脂/玻璃纤维(EP/GF)复合材料导热性能,首先针对各向同性模型,利用瞬态平面热源(TPS)法以及瞬态热线法研究了取样方式和位置对热导率的影响,并对两种方法测试结果的差异性展开讨论。针对各向异性模型,利用TPS法探讨纤维方向同热导率的关系,通过串并联模型验证测定结果,同时拟合不同温度下热导率,计算液氢温区EP/GF热导率。结果表明,EP/GF导热性能同取样方式相关,与取样位置无关;测试过程中EP/GF内部纤维纱线传递作用不同,造成两种测试方法测定结果的差异性;沿着纤维方向热导率大于垂直于纤维方向热导率;砂纸打磨后,树脂基体软化分解,玻璃纤维裸露,接触界面微凸体增多,造成EP/GF作支撑构件时其热导率随着磨损老化而增大。所得结论可为EP/GF用作支撑构件提供科学理论依据。

In order to investigate the thermal conductivity of epoxy/glass fibre(EP/GF)composites,the thermal conductivity was firstly determined for the isotropic model by using the transient plane source(TPS)method and the transient hot wire method to demonstrate the effects of sampling method and location on the thermal conductivity,and the differences between the results of the two measurement methods were also analysed.Then,the relationship between fibre orientation and thermal conductivity was investi‐gated using the TPS method for the anisotropic model,and the results were verified using a series-parallel model.Meanwhile,the thermal conductivity at varying temperatures was fitted to calculate the thermal conductivity of EP/GF in the liquid hydrogen tem‐perature region.The results show that the thermal conductivity of EP/GF is related to the sampling method and unrelated to the loca‐tion of the sampling.The difference in transfer of internal fibre yarns of EP/GF during testing contributes to the difference in the de‐termination of the two measurement methods.The thermal conductivity along the fibres is greater than the thermal conductivity verti‐cally to the fibres.The resin matrix softens and decomposes after sanding,as well as the glass fibres become bared and the number of micro convex at the contact interfaces increases,which results in an increase in the thermal conductivity of EP/GF as a support structure with wearing.The results obtained can provide a scientific and theoretical basis for the use of EP/GF as a support structure.