复杂杯杆件温冷联合精密成形数值模拟及工艺优化

发布时间：2018-01-18 05:12

  本文关键词：复杂杯杆件温冷联合精密成形数值模拟及工艺优化　出处：《长春工业大学》2016年硕士论文　论文类型：学位论文

  更多相关文章： 复杂杯杆零件 温冷联合工艺 数值模拟 模具磨损 参数优化

【摘要】：随着汽车行业的快速发展和日益激烈的市场竞争,人们对汽车的安全性能及舒适性能要求越来越高。汽车转向系统的性能好坏直接影响整车性能,汽车转向螺杆作为汽车转向系统的一个重要零部件,其性能的好坏同样直接影响转向系统可靠性,进而影响整车性能。汽车转向螺杆是典型杯杆型零件,其形状复杂,精度要求高,可通过温冷联合挤压成形工艺达到其形状和精度要求。本文通过利用有限元数值模拟来分析汽车转向螺杆在温冷联合技术下的成形,对汽车转向螺杆的成形工艺进行比较,并确定成形工艺方案,同时对温挤压凹模进行磨损分析。首先,对汽车转向螺杆制定两种可行的温冷结合工艺方案,即多工序复合挤压成形和两工序复合挤压成形(杯杆复合成形工艺)。利用有限元模拟软件Deform对两种工艺方案进行热力耦合数值模拟,获得成形过程中每道工序的成形时间-载荷曲线图、速度场分布矢量图、并观察成形过程中出现的问题,以此作为比较标准,对两种工艺方案进行对比,最终选择两工序复合挤压作为成形工艺。其次,在温挤压内孔工序时,磨损是影响凹模寿命的主要因素。结合正交试验法和基于Archard磨损模型下的有限元数值模拟法,对温挤压凹模磨损进行分析,选择凹模入口圆角半径r、模具初始温度t、模具初始硬度HRC,摩擦因子m为影响凹模磨损的四个参数因素,并选择不同因素的4个水平,确定了L16(45)正交试验方案,通过极差分析和方差分析得出凹模入口圆角半径2mm、模具初始温度350℃、模具初始硬度HRC55,摩擦因子0.2为使凹模磨损量最小的最优组合,对最优工艺参数组合进行建模、数值模拟分析,得出凹模磨损量,进行模具寿命的预测。最后,由于智能算法的推广应用和正交试验分析的局部性问题。使用影响凹模磨损的四个参数组合与在有限元数值模拟下的模具磨损量组成32组数据样本,训练BP神经网络,建立凹模入口圆角半径r、模具初始温度t、模具初始硬度HRC,摩擦因子m与凹模磨损量之间的映射关系,以温挤压凹模磨损量为目标函数,通过遗传算法对四个影响因素进行组合优化,使凹模磨损量最小。研究结果显示:采用本方法优化参数得出的最大磨损量与正交实验法相比降低了12.35%,说明该设计方法是可行的。
[Abstract]:With the rapid development of the automobile industry and the increasingly fierce market competition, people have higher and higher requirements for the safety and comfort performance of the vehicle. The performance of the automobile steering system has a direct impact on the performance of the whole vehicle. As an important part of automobile steering system, the performance of steering screw also directly affects the reliability of steering system and further affects the performance of the whole vehicle. The steering screw is a typical cup rod part. The shape and precision can be achieved by the combined extrusion process of temperature and cold. In this paper, finite element numerical simulation is used to analyze the forming of automobile steering screw under the combined technology of temperature and cold. The forming process of automobile steering screw is compared, and the forming process scheme is determined. At the same time, the wear analysis of warm extrusion die is carried out. Firstly, two feasible warm and cold combination process schemes are made for automobile steering screw. That is, multi-process composite extrusion forming and two-process composite extrusion forming (cup bar composite forming process). The thermo-mechanical coupling numerical simulation of the two process schemes is carried out by using finite element simulation software Deform. The forming time-load curve and velocity field distribution vector diagram of each process are obtained, and the problems in the forming process are observed, which is taken as the comparison standard to compare the two process schemes. Finally, two processes of composite extrusion as the forming process. Secondly, in the warm extrusion process of the inner hole. Wear is the main factor affecting die life. Combined with orthogonal test method and finite element numerical simulation method based on Archard wear model, die wear of warm extrusion die is analyzed. Four parameter factors affecting the wear of the die are selected: the inlet radius r, the initial temperature t, the initial hardness HRC, the friction factor m, and the four levels of different factors. L1645) orthogonal test scheme was determined. By means of range analysis and variance analysis, the inlet radius of the die was 2 mm, the initial temperature of the die was 350 鈩，

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