基于响应曲面法的预成形模具优化设计研究

发布时间：2018-05-21 10:05

本文选题：锻造 + 预成形模具设计　；参考：《山东大学》2017年硕士论文

【摘要】：锻造作为材料塑性加工的重要方法,具有产品精度高、性能优、加工效率高等优点,在汽车、飞机、轮船等零部件生产的机械制造业中有着广泛的应用。随着科学技术的不断进步和社会经济的不断发展,各机械制造业对零部件生产的要求越来越高,不仅要求提高生产质量和生产效率,还要求降低生产成本,因此需要对锻造过程的有关工艺参数进行优化。本文在分析了各种优化设计方法和理论的基础上,采用响应曲面法对锻造中的预锻模形状进行优化设计。根据锻造生产的实际需求明确了优化目标,即锻件形状符合要求且飞边最小和锻件的微观组织均匀化两个优化目标,并分别构建了相应的目标函数。以工字型锻件为例,对预成形模具形状进行了设计,设计出了直线、圆弧和曲线三种形状,并以直线的角度、圆弧的半径、曲线的拐点为设计变量进行优化。以有限元数值模拟技术为实验手段,对不同形状的预成形模具进行锻造过程模拟,根据模拟出的实验数据求得目标函数值。用曲线拟合软件对形状设计变量和目标函数值进行曲线拟合,得到相应的曲线方程,并对曲线方程求最优解,从而获得最佳预成形模具形状。以锻件形状为优化目标时,曲线形预锻模优化后产生的飞边最小;以锻件微观组织均匀化为优化目标时,直线形预锻模优化后的微观组织分布最均匀。本文还对锻造成形过程进行了多目标优化,建立了同时以锻件形状和微观组织均匀化为优化目标的多目标优化模型,采用线性加权的方法将形状优化子目标函数和微观组织优化子目标函数构成一个总目标函数。通过三种预锻模形状的优化和对比,直线形预锻模形状优化后总目标函数值最小,且终锻件能够充满型腔,达到了锻件形状和微观组织性能的综合最优。
[Abstract]:As an important method of material plastic processing, forging has many advantages such as high product precision, excellent performance and high processing efficiency. It is widely used in mechanical manufacturing of automobile, aircraft, ship and other parts. With the continuous progress of science and technology and the development of social economy, the requirements of the mechanical manufacturing industry for the production of components are becoming higher and higher, not only to improve the quality and efficiency of production, but also to reduce the cost of production. Therefore, it is necessary to optimize the process parameters of the forging process. Based on the analysis of various optimization design methods and theories, this paper uses the response surface method to optimize the shape of preforging die in forging. According to the actual demand of forging production, the optimization goal is defined, that is, the forging shape meets the requirements and the minimum flange and the microstructure of the forging are homogenized, and the corresponding objective functions are constructed respectively. Taking I-shaped forgings as an example, the shape of preformed die is designed. Three shapes, namely, straight line, arc and curve, are designed and optimized with the angle of straight line, radius of arc and inflection point of curve as design variables. The forging process of preformed die with different shapes was simulated by finite element numerical simulation technique. The objective function value was obtained according to the simulated experimental data. The curve fitting software is used to fit the shape design variable and the objective function value, and the corresponding curve equation is obtained, and the optimal solution to the curve equation is obtained, so as to obtain the best shape of the preforming die. When the shape of forgings is taken as the optimization object, the minimum flange is produced after the curved preforging die is optimized, and the microstructure distribution of the optimized linear preforging die is the most uniform when the microstructure of the forging is homogenized as the optimization objective. In this paper, multi-objective optimization of forging forming process is also carried out, and a multi-objective optimization model is established in which the shape and microstructure of forgings are homogenized as the optimization objectives at the same time. The shape optimization subobjective function and the microstructure optimization subobjective function are used to form a total objective function. Through the optimization and comparison of three kinds of preforging die shape, the total objective function value of linear preforging die shape optimization is minimum, and the final forging can be filled with cavity, which achieves the comprehensive optimum of forgings shape and microstructure and properties.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG315.2

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