采用光纤法对碳纤维增强树脂基复合材料沿纤维方向的热膨胀应变进行测试, 然后分别用传统的片状模型和改进模型对复合材料沿纤维方向的热膨胀应变进行了理论计算, 将计算结果与测试结果进行对比分析; 之后利用改进模型和ABAQUS有限元软件分别计算得到了复合材料沿垂直于纤维方向的热应力, 并利用有限元模拟了纤维排布对热应力的影响, 得到了热应力的分布。结果表明: 随着温度升高, 复合材料的热膨胀应变基本呈线性增加, 纤维分布集中区域的热应力可达到一般区域的1.5倍以上, 应力集中现象产生于纤维与基体的接触处; 与片状模型相比, 改进模型计算得到的热应变与试验结果更吻合, 误差小于10%, 证明了改进模型的正确性和所建有限元模型的合理性。

The thermal expansion strain in parallel direction of carbon fiber reinforced resin composite was tested by fiber Bragg grating sensor. Layer model and modified model were used to calculate the thermal expansion strain in parallel direction respectively. The experimental results were compared with the calculated results. Thermal stress in perpendicular direction was calculated by modified model and ABAQUS finite element software separately, and the software was also used to simulate the effect of fiber arrangement on thermal stress, thus the distribution of thermal stress was obtained. The results show that with the increase of temperature, the thermal expansion strain of the composite increased linearly, thermal stress of fiber concentrated region was 1.5 times greater than other areas, stress concentration phenomenon occured at the interface between fiber and the substrate. Compared with the layer model, the thermal strain calculated by the modified model was more accurate, and the error between modified model and the experiment result was less than 10%, this indicating the accuracy of modified model and the reasonableness of the finite element model.