弹簧座论文：弹簧座冲压成形数值模拟及工艺优化.doc

弹簧座论文：弹簧座冲压成形数值模拟及工艺优化

【中文摘要】弹簧座由于其螺旋面带来的非对称性,使其冲压成形过程中的受力变形状态要比一般的对称件复杂得多。按照工厂原有工艺流程进行生产时,其拉深工件在凸台侧壁等质量关键部位厚度分布极不均匀,增厚、变薄都相当严重而达不到产品质量要求；翻边工件局部有破裂的趋势；翻孔工件极易在U形缺口处产生裂纹,产品质量难以控制。为克服弹簧座的成形缺陷及探明成形特点,本文利用数值模拟技术,建立了零件拉深、翻边等整个成形过程数值模型,以特征点的形式呈现出了拉深工件质量关键部位的变形特点,并通过多工步模拟反应出了厚度、应变状态等信息在工序间的传递情况。工序间的应变及厚度变化信息表明,后一工序基本上不影响前一工序所确定的成形质量,可以通过调整单一工序逐个改善各缺陷部位的质量来提高总体质量。针对拉深工件的质量问题,在模拟试验基础上以凸台部位的凸模圆角半径和模具间隙为影响因素建立了拉深工件质量关键部位材料的最大减薄率和最大增厚率的回归分析模型。根据两回归分析模型对工件质量进行了多目标优化,得出了质量评价模型,拟出了可生产出合格工件的最佳工艺参数。针对翻边工件质量状况进行了工艺参数可行性分析,分别得出了对模具间隙、凹模圆角半径或凸模圆角半径进行单一调整即可达到工件质量要求的工艺参数。针对翻孔过程中U形缺口边缘出现的破裂现象,在数值模拟的基础上运用正交试验对合理工艺参数展开了寻找。由试验结果表明,限于零件缺口的位置要求,很难以调整工艺参数的方式来完全克服产品的破裂缺陷,需要调整工序内容来改善零件的成形质量。通过调整冲孔、翻孔等工序内容后,产品的质量得到了保证。
【英文摘要】Because of its spiral surface which causes asymmetry, the deformation state of spring seat in the stamping process is much more complicated than that of general symmetry part. Accordance with the original production process,as the thickness distribution of drawing workpiece is extremely uneven in key positions, boss,thickening and thinning are too serious to meet the quality requirements of product;workpiece of flanging has risk of crack;in the hole flanging operation,cracks extremely easily occur on the edge of U-notch,which make the quality of product too difficult to control.In order to overcome the defects and ascertain the forming characteristics of the spring seat, using numerical simulation technology, this paper establishes all of the numerical simulation models of the forming process which include drawing,flanging, and hole flanging.The deformation characteristics of drawing workpiece in the key positions are presented by several feature points.Through the multi-step simulation in this paper, the transfer about thickness, strain and other information are well reflected.The information of thickness and strain in diferent operations show that the forming quality which evaluationed by the previous operation does not suffer the influence of the next one. Therefore, the overall quality of spring seat can be improved in the manner of improving the quality of defective position step by step,by carrying out single operation.In view of the drawinig workpiece’s forming quality problem, two regression models between the process parameters and the rates of maximum thinning and thickening are established by regression analysis using punch profile radius and die clearance in the part of the boss, based on simulation test. According to the regression models mentioned just now,multi-objective optimization is achieved and an model of overall quality is educed. Optimum parameters that can produce qualified workpiece are figured out.Aimed at the quality status of flanging workpiece, feasibility of process parameters are tested,and its available values are displayed which make quality improvement can be achieved just by adjusting die clearance, die profile radius or punch profile radius.In order to prevent cracking phenomena from occurring on the edge of U-notch in hole flanging process, orthogonal test is taken to find reasonable process parameters.The test result showing that it is difficult to overcome the defects of product completely by adjusting process parameters, which indicates that operations need to be ameliorated.By rectifying punching and hole flanging,the quality of the spring seat is ensured.
【关键词】弹簧座 冲压成形 数值模拟 回归分析 多目标优化
【英文关键词】spring seat stamping forming numerical simulation regression analysis multi-objective optimization
【目录】弹簧座冲压成形数值模拟及工艺优化

摘要

3-4

ABSTRACT

4-5

第1章 绪论

8-17

1.1 引言

8-9

1.2 冲压成形数值模拟技术的发展与应用

9-13

1.3 本文的研究意义及主要研究内容

13-15

1.3.1 课题的来源及研究意义

13-14

1.3.2 本文的研究内容

14-15

1.4 课题模拟软件简介

15-17

第2章 冲压成形数值模拟基本理论

17-27

2.1 物体变形描述

17-18

2.2 有限元显示积分算法表述

18-19

2.3 单元类型的选取与对比

19-21

2.3.1 单元的选取

19-20

2.3.2 单元分析对比

20-21

2.4 沙漏现象及其控制

21-22

2.4.1 沙漏现象

21-22

2.4.2 沙漏控制

22

2.5 屈服准则及其对应的材料模型

22-24

2.6 接触及摩擦处理

24-27

第3章 弹簧座成形特点分析

27-40

3.1 弹簧座原有工艺简介

27-30

3.1.1 零件相关基本信息

27-28

3.1.2 原有工艺流程的模具简介

28-30

3.2 拉深成形过程分析

30-36

3.21 拉深有限元模型的建立

30-31

3.2.2 拉深模拟结果及其分析

31-36

3.3 其它工序分析

36-40

3.3.1 其它工序有限元模型的建立

36-37

3.3.2 其它工序模拟结果及其分析

37-40

第4章 弹簧座拉深工艺参数优化

40-58

4.1 建立主要工艺参数回归模型

40-49

4.1.1 二次回归正交组合设计方法介绍

40-46

4.1.2 试验设计及分析

46-49

4.2 回归模型的响应曲面分析

49-53

4.2.1 响应模型求解的基本思想

49-51

4.2.2 拉深回归模型分析

51-53

4.3 拉深主要成形参数综合优化

53-58

4.3.1 多目标函数优化问题的表述

53-56

4.3.2 拉深成形参数统一优化设计

56-58

第5章 弹簧座其它工序的调整与优化

58-63

5.1 翻边工序的工艺改进

58-59

5.2 翻孔工序的工艺改进

59-63

第6章 总结与展望

63-65

6.1 总结

63-64

6.2 展望

64-65

致谢

65-66

参考文献

66-70

攻读学位期间的研究成果

70