模具间隙对热成型的影响及其优化方法

发布时间：2018-10-16 13:42

【摘要】：随着汽车行业的蓬勃发展,人们对汽车轻量化和碰撞安全性的要求越来越高,热成型技术在汽车车身零部件的制造中得到了广泛应用,热成型技术的研究也越来越被广大学者所重视。本文通过实验和仿真相结合的方法,研究了模具间隙对热成型温度分布和成型件力学性能的影响,主要完成了以下工作:1提出了一种冲压模模具闭合间隙的监测方法,不仅为研究模具间隙对热成型的影响提供了可靠的测量依据,还可应用于模具调试及冲压质量的监测。首先对电涡流位移传感器进行标定,获取了传感器的有效测量区间。再设计一套模具间隙测量实验,通过对称板与非对称板的冲压间隙监测,讨论了该方法的可靠性。2通过调整凸、凹模模具间隙,做了不同间隙下U型件的热成型实验,并做了相应条件下的热成型仿真,研究了模具间隙对热成型板料温度分布及试件相关力学性能的影响。完成了0.9t、1.0t、1.1t和1.2t(t为板料厚度)四种模具间隙下的热成型实验及仿真工作,得到了相应的温度分布曲线,对比了四种条件下成型件的力学性能。3研究了模具不均匀间隙产生的原因,从模具设计角度入手,提出了一种基于有限元分析的拉延模压力中心的确定方法。阐述了新的压力中心确定方法的原理,通过某型汽车B柱对新方法进行了具体说明,发现压力中心与模具几何中心存在一定的差异。同时讨论了模具在垂直方向上偏转力矩对冲压力的影响。本文所研究的模具间隙对热成型的影响,对今后热成型研究有一定的借鉴意义。文中所提出的两种新方法,对热成型乃至整个冲压行业都具有一定的指导意义。
[Abstract]:With the rapid development of automobile industry, people are demanding more and more light weight and collision safety. The hot forming technology has been widely used in the manufacture of automobile body parts. The research of thermoforming technology has been paid more and more attention by many scholars. In this paper, the influence of die clearance on the temperature distribution of hot forming and mechanical properties of forming parts is studied by means of experiment and simulation. The main work is as follows: 1. A monitoring method for closing clearance of stamping die is proposed. It not only provides a reliable measurement basis for studying the influence of die clearance on hot forming, but also can be used in die debugging and stamping quality monitoring. Firstly, the eddy current displacement sensor is calibrated, and the effective measurement interval is obtained. A set of die clearance measurement experiments are designed. The reliability of the method is discussed by monitoring the punching gap between symmetric plate and asymmetric plate. 2 by adjusting the die clearance of convex and concave die, the hot forming experiments of U-shaped parts with different gaps are done. The influence of die clearance on the temperature distribution of hot forming sheet and the mechanical properties of the specimen was studied. The thermal forming experiment and simulation work under four kinds of die clearance of 0.9t ~ 1.0t ~ 1.0t and 1.2t (t = sheet thickness) were completed, the corresponding temperature distribution curves were obtained, and the mechanical properties of the molded parts under four conditions were compared. 3 the causes of the non-uniform gap of the die were studied. From the angle of die design, a method of determining the pressure center of drawing die based on finite element analysis is put forward. This paper expounds the principle of the new method of determining the pressure center, and explains the new method by means of a certain type of automobile B column. It is found that there is a certain difference between the pressure center and the geometric center of the die. At the same time, the influence of the deflection moment on the pressure of the die is discussed. The influence of die clearance on thermal forming is useful for future research. The two new methods proposed in this paper have certain guiding significance for hot forming and even the whole stamping industry.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG306

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