玻璃纤维缠绕件芯模的优化研究

发布时间：2019-03-01 11:05

【摘要】：随着科学技术的飞速发展,复合材料兼具多种材料优良性能的特性在世界上被广泛的开发,逐步应用到航天、军事等多种领域。在复合材料制品的成型质量中制造工艺与材料性能具有同等地位。与以往外固化成型方法不同,热芯缠绕工艺采用加热管在芯模内部通入高温水蒸汽的方法将复合材料的缠绕与加热固化两道工序同步化,有效的减少设备和占地面积、降低工人操作的复杂性,提高了成型效率,使复合材料实现了边缠绕边固化的一体化成型。复合材料缠绕制品中环氧树脂的使用频率很高。环氧树脂是热塑性材料,固化中需控制的温度特征参数很多,温度的精准控制是关键。当前温控中最突出的问题是加热时芯模轴向温度分布不均匀,这与芯模内部加热管道的结构存在直接关系:高温水蒸汽在芯模内部进行循环时,在封闭式尾部处对流效果不理想和存在流量、温度损失,使得复合材料在成型过程中首尾受热不均匀,可能存在应力变形、分层等现象。而且圆形导气孔口附近的芯模外表面温度等温线呈同心圆分布,内外温差较大,导致此处的壳体局部更易分层。针对以上问题,本文介绍了常用缠绕设备和复合材料壳体成型质量影响因素,建立了芯模内部加热管道蒸汽物理模型。基于流体分析软件FLUENT用二维模型对水蒸汽在加热管中的流场分布进行仿真,根据仿真速度云图和节点图分析了导气孔处的蒸汽速度与入口蒸汽流速以及加热管道结构之间的关系。根据分析结果对加热管改进,并对优化前和优化后的芯模管道进行了三维热流耦合:结果显示优化后的芯模内表面上的温度分布能满足预期要求,同时表明研究中温度轴向分布不均匀的因素是流量。最后,针对导气孔处芯模温度同心分布温差较大问题,运用射流理论分析了圆孔口不利于蒸汽扩散的原因,分析结果显示矩形孔是更理想的孔口形状。
[Abstract]:With the rapid development of science and technology, composite materials with excellent properties of a variety of materials have been widely developed in the world, gradually applied to aerospace, military and other fields. The manufacturing process has the same position as the material properties in the molding quality of composite products. Different from the previous external curing molding methods, the hot core winding process adopts the method of heating tube filling high temperature water vapor inside the core mold to synchronize the winding and heating curing processes of composite materials, thus effectively reducing the equipment and the area occupied. It reduces the complexity of workers' operation, improves the forming efficiency, and realizes the integral molding of edge winding and side curing of composite materials. The use frequency of epoxy resin in composite winding products is very high. Epoxy resin is a thermoplastic material. There are many temperature characteristic parameters to be controlled in curing, and the precise control of temperature is the key. The most prominent problem in the current temperature control is that the axial temperature distribution of the core die is not uniform when heating, which is directly related to the structure of the heating pipe inside the core mold: when the high temperature water vapor is circulating in the core mold, In the closed tail, the convection effect is not ideal and there is flow rate and temperature loss, which makes the composite non-uniform at the beginning and end of the molding process, and may have the phenomena of stress and deformation, delamination and so on. Moreover, the temperature isotherms on the outer surface of the core die near the circular orifice are concentric and the temperature difference between inside and outside is large, which leads to the local layering of the shell. In view of the above problems, this paper introduces the factors influencing the molding quality of the common winding equipment and composite shell, and establishes the steam physical model of the heating pipe inside the mandrel. Based on the fluid analysis software FLUENT, the two-dimensional model is used to simulate the flow field distribution of water vapor in the heating pipe. Based on the simulated velocity cloud and node diagram, the relationship between the steam velocity at the orifice and the inlet steam velocity as well as the heating pipe structure is analyzed. According to the analysis results, the heating pipe is improved, and the three-dimensional heat flux coupling is carried out on the core pipe before and after optimization. The results show that the temperature distribution on the inner surface of the optimized core mold can meet the expected requirements. At the same time, it is shown that the factor of uneven axial distribution of temperature in the study is the flow rate. Finally, aiming at the problem of large temperature difference of the core mold temperature distribution in the air guide hole, the reasons why the circular orifice is not conducive to steam diffusion are analyzed by means of jet theory. The results show that the rectangular hole is a more ideal orifice shape.
【学位授予单位】：中北大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB332

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