三维机织碳纤维/环氧树脂复合材料在两种测量方法下的热响应机制对比

采用瞬态热线法和闪光法分别测量了多种结构参数的三维机织碳纤维/环氧树脂复合材料的导热系数。通过对3D正交机织碳纤维/环氧树脂复合材料的有限元模拟可以看出，3D正交机织碳纤维/环氧树脂复合材料内经纱、纬纱和Z向纱的导热作用在不同的受热形式下会发生变化。采用瞬态热线法测量时，2.5D机织碳纤维/环氧树脂复合材料的导热系数低于2.5D经向增强结构，同时高于3D正交结构，而采用闪光法测量时，2.5D经向增强和3D正交碳纤维/环氧树脂复合材料的导热系数均小于2.5D机织结构。这是由于在使用不同的测量方法时，三维机织碳纤维/环氧树脂复合材料内部相同的纱线系统在导热过程中所起的作用并不相同。随着纤维体积含量的提高，瞬态热线法和闪光法测得的2.5D机织碳纤维/环氧树脂复合材料的导热系数都在不断提高。由于经纱的屈曲，采用闪光法测量时，导热性能提升更加明显。研究结果表明，三维机织碳纤维/环氧树脂复合材料在不同受热形式下具有不同的热响应机制。

Comparison of thermal response mechanisms for three dimensional woven carbon fiber/epoxy resin composites under two measurement methods

Thermal conductivities of 3D woven carbon fiber/epoxy resin composites with different structures were measured by using transient hot-wire method and flash method, respectively. From the finite elemental simulations of 3D orthogonal woven carbon fiber/epoxy resin composites, it can be seen that, the roles of the warp, weft and Z-yarn in heat transfer process change with the change of the measuring method. By using transient hot-wire method, the thermal conductivity of 2.5D woven carbon fiber/epoxy resin composite is higher than warp-reinforced 2.5D, but lower than 3D orthogonal. However, the thermal conductivities of warp-reinforced 2.5D and 3D orthogonal woven carbon fiber/epoxy resin composites are less than 2.5D by using flash method. That is because of that, the same yarn in 3D woven carbon fiber/epoxy resin composites plays distinct roles in heat transfer process by using different measurement methods. Thermal conductivities of 2.5D woven carbon fiber/epoxy resin composites obtained by using transient hot-wire method and flash method increase with the increasing of fiber volume fraction. In addition, the increase of thermal conductivity obtained by flash method is more obvious, which is caused by the crime of warp. Based on these investigation. it can be concluded that the thermal response mechanisms of 3D woven carbon fiber/epoxy resin composites under different heating modes are different.