复合材料构件热压罐固化的温度场分析与调控

发布时间：2019-07-03 15:10

【摘要】：因为树脂基复合材料的比强度和比模量相对于传统金属材料要高,现如今已被大量应用在航空航天领域,同时热压罐工艺作为制造航空复合材料结构的主要方法也吸引了大量的学者研究。随着研究的深入,人们发现复合材料结构在成型过程中,由于本身结构件和模具体积较大且结构复杂,阻碍了热压罐内热气体的流动,引起了复合材料固化温度分布不均匀,其内部产生残余应力且结构发生变形,严重影响产品的质量和性能。为了改善热压罐中复合材料成型的质量,同时保证成本低和周期短,人们提出使用数值仿真的方法研究热压罐工艺的温度分布,预报复合材料固化过程中可能出现质量问题的地方,提出工艺改善意见。本文从三个方面研究了热压罐中复合材料构件和模具的温度变化及流场的分布规律。第一部分使用ICEM软件和Fluent软件建立了框架式模具在热压罐中强迫对流换热的有限元模型,依据罐内气体的流态,采取标准κ-ε湍流模型作为热压罐中气体流动模型,随后验证了模拟结果的正确性。依据该模型讨论热压罐工艺参数中升/降温速率和风速对模具温度分布的影响规律。第二部分内容基于固体热传导方程和树脂固化放热方程,建立了包括聚酯树脂和环氧树脂层合板的固化模型,验证了模型的正确性。随后研究了对流换热系数、厚度等工艺参数对层合板固化进程中的温度分布和固化度变化。第三部分内容利用Fluent软件对热压罐成型工艺中蒙皮结构的温度场和流场特性进行了模拟分析,并通过在框架式模具通风孔处安装风扇的方法来增强热空气对流,改善罐内流场分布均匀性和模具型面温度分布均匀性。计算结果表明,合理地布置风扇在模具通风孔中的位置和控制风速,可以调整框架式模具内部区域流场分布,使模具型面的温度场更均匀,对于提高复合材料构件成型质量具有重要意义。
[Abstract]:Because the specific strength and modulus of resin matrix composites are higher than those of traditional metal materials, they have been widely used in aerospace field. At the same time, hot pressing tank technology as the main method of manufacturing aviation composite structure has attracted a large number of scholars. With the deepening of the research, it is found that in the molding process, the large volume and complex structure of the composite structure and die hinder the flow of hot gas in the hot pressing tank, resulting in uneven curing temperature distribution of the composite, resulting in residual stress and structural deformation in the composite, which seriously affects the quality and properties of the product. In order to improve the quality of composite material forming in hot pressing tank and ensure the low cost and short cycle, numerical simulation method is proposed to study the temperature distribution of hot pressing tank process, predict the possible quality problems in the curing process of composite materials, and put forward some suggestions for process improvement. In this paper, the temperature variation and flow field distribution of composite components and dies in hot pressing tank are studied from three aspects. In the first part, the finite element model of forced convective heat transfer of frame die in hot pressure tank is established by using ICEM software and Fluent software. According to the gas flow pattern in the tank, the standard k-蔚 turbulence model is used as the gas flow model in the hot pressing tank, and then the correctness of the simulation results is verified. According to the model, the effects of rising / cooling rate and wind speed on the temperature distribution of hot pressing tank are discussed. In the second part, based on the solid heat conduction equation and resin curing heat release equation, the curing model of polyester resin and epoxy resin laminates is established, and the correctness of the model is verified. Then the temperature distribution and curing degree of laminated plates during curing process were studied by convective heat transfer coefficient, thickness and other process parameters. In the third part, the temperature field and flow field characteristics of the skin structure in the hot pressing tank molding process are simulated and analyzed by using Fluent software, and the hot air convection is enhanced by installing the fan at the vent hole of the frame die, and the uniformity of flow field distribution in the tank and the temperature distribution uniformity of the die profile are improved. The calculation results show that the reasonable arrangement of fan position and control wind speed in die vents can adjust the flow field distribution in the internal area of frame die and make the temperature field of die surface more uniform, which is of great significance to improve the molding quality of composite components.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB33

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