基于有限元方法的复合材料热压成型模具设计

Design of Composite Hot Pressing Die Based on Finite Element Method

热压罐工艺广泛用于热固性基体复合材料的制造过程中。在此过程中,热压罐内温度分布的不均匀性可能导致复合材料的非同步固化,从而降低复合材料零件的机械性能。为了提高固化性能,必须对热压罐模具进行优化设计。通过建立基于有限元分析法的数值模型来模拟热压罐内的温度分布,并对已知的实验数据进行验证。然后,将覆盖有复合材料和简化辅助材料的典型模具结构引入数值模型。此外,以复合材料零件固化度的最大标准偏差为目标,以提升情况下模具的变形为约束,提出了一种将数值模型与遗传算法相结合的方法来优化模具子结构的设计参数,以提高固化的同步性。结果复合材料零件固化度的最大标准偏差提高了17.21%,这表明采用所提出的方法实现了更好的固化同步。

Autoclave process is widely used in manufacturing processes of thermosetting matrix composite materials.In this process,the non-uniformity of temperature distribution in autoclave may result in non-synchronous curing of composites,which in turn reduces the mechanical properties of composite parts.In order to improve the curing performance,design optimization of autoclave molds has to be performed.In this paper,a finite volume method-based numerical model was established to simulate the temperature distribution inside an autoclave and it’s verified by known experimental data.Then,a typical mold structure covered with composites and simplified auxiliary materials was introduced to the numerical model;in addition,aiming at the maximum standard deviation of the curing degree of the composite part,and taking the deformation of the die in the lifting case as the constraint,a method combining the numerical model and the genetic algorithm was proposed to optimize the design parameters of the die substructure so as to improve the curing synchronization.Results show that the maximum standard deviation of the curing degree of composite parts can be increased by 17.21%,which indicates that better curing synchronization can be achieved by using the method proposed.