基于热气加热的热塑性复合材料原位成型过程中温度场分析

Analysis of temperature field for thermoplastic composites based on hot gas heating in an in-situ consolidation process

在热塑性复合材料的自动铺放原位成型过程中,温度历程对于复合材料的最终质量和性能有很大影响。以碳纤维增强聚醚醚酮铺放过程中的温度场为研究对象,建立了二维温度场瞬态传热模型,通过对传热模型划分区域确立了边界条件,分析了热气温度、铺放速度以及模具的初始温度对铺层温度场的影响。通过原理性铺放实验,建立了温度场测量系统,从而验证了有限元模型的正确性。结果表明,随着热气温度的升高以及铺放速度的降低,每层的峰值温度逐渐升高。模具初始温度为室温时,为满足成型要求,选择热气温度为650℃,最大铺放速度为6 mm/s。模具的初始温度对于首层的温度场有很大影响,为改善首层粘接熔融效果、提高铺放效率以及降低整体温度梯度,应适当提高模具温度和铺放速度,并降低热气温度。

During the automated fiber placement and in-situ consolidation process of thermoplastic composites,the temperature history has a great influence on the final quality and performance of composites.Taking the temperature field during the laying process of the carbon fiber reinforced peek as the research object,a two-dimensional transient heat transfer model of the temperature field was established,the boundary conditions were established by dividing the model.The influence of the hot gas temperature,laying speed and the initial temperature of the mold on the temperature field of the layers was analyzed.Through the principle laying experiment,the temperature field measurement system was established,which verified the correctness of the finite element model.The results show that with the increase of the hot gas temperature and the decrease of the laying speed,the peak temperature of each layer gradually increases.When the initial temperature of the mold is room temperature,in order to meet the molding requirements,the hot gas temperature is 650℃and the maximum laying speed is 6 mm/s.The initial temperature of the mold has a great influence on the temperature field of the first layer.In order to improve the bonding and melting effect of the first layer,increase the laying efficiency and reduce the overall temperature gradient,the mold temperature and the laying speed should be appropriately increased,and the hot gas temperature should be reduced.