CFRP拉挤过程非稳态温度场数值模拟与FBG实时检测

Simulation of unsteady temperature profile during CFRP pultrusion and detection by FBG

碳纤维增强聚合物基复合材料的拉挤成型过程是动态的,其固化度与温度变化为强耦合关系。温度场是工艺过程控制关键之一。根据固化动力学和传热学理论,建立了非稳态温度场与固化动力学数学模型。通过差示扫描量热仪(DSC)分析计算出模型中固化动力学参数。采用有限元与有限差分相结合的方法,依据ANSYS求解耦合场的间接耦合法,编制了计算程序,对拉挤工艺不同工况CFRP内部非稳态温度场进行数值模拟。采用专门设计制作的铝毛细管封装的布拉格光栅光纤(FBG),排除了非温度应变的干扰。通过试验确定了FBG温度传感特性表征及FBG温度灵敏度系数值,保障了CFRP内部温度场实时动态检测的准确度。模拟与实验结果基本吻合,为取代传统试凑性实验,优化CFRP拉挤工艺提供了科学快捷的理论依据。

The pultrusion of the carbon fiber reinforced plastics （CFRP） is a dynamic process. The degree of cure and temperature are coupled during this process. According to the curing kinetics and the heat transfer theory, the models of unsteady temperature filed and curing were established. The kinetic parameters used to predict the temperature profile were obtained from differential scanning calorimetry （DSC）. The finite element method and finite difference method were combined, and the indirect decoupling method based on ANSYS was adopted to simulate the temperature profile in FRP during pultrusion. The fiber Bragg grating （FBG） was encapsulated in an aluminum capillary in order to exclude the non-temperature influence. The feature and the temperature sensitivity coefficient were acquired through experiment to guarantee the accuracy of the real-time temperature detecting. The simulative result is in good agreement with the experimental one. The simulative method makes convenience for the optimization of technology parameters of pultrusion and takes the place of the traditional trial-and-error method.