两道次渐进成形圆孔翻边的模拟研究

论文总字数：44332字

摘 要

金属板料翻边工艺是一种特殊的板料成形工艺，其被广泛地应用在制造业的各行各业。目前为止，板料的翻边工艺是基于冲压模具而开展的。与此同时，模具的制造费用却非常高昂，模具的制作周期较长，因此很大程度上制约了翻边工艺的发展。为了解决这一问题，提出了一种新的板料成形方法——板料渐进成形工艺。板料渐进成形工艺利用“分层”制造的思想，通过控制工具头的移动压迫板料逐层发生变形。因此板料渐进成形工艺并不需要制造特定的模具，且具有成形极限大、制件复杂程度高、加工柔性高、灵活度高等诸多优点。本文将借助DYNAFORM5.9以及UG10.0计算机建模软件与LS-DYNA求解器，利用数值模拟的实验方法对板料成形过程进行模拟仿真。通过分析模拟结果，总结出渐进成形圆孔翻边过程的变形特点。最终将模拟结果与实际实验结果进行对比，验证计算机软件中所建立有限元模型的可信性。

本文针对单道次渐进成形路径下的厚度分布不均问题，探讨了两种新的具有一定曲率的第一道次成形轨迹下的两道次渐进成形圆孔翻边变形特点，总结各种加工路径的发展逻辑，并且就通过改变定曲率曲线路径的曲率大小、板料的初始厚度以及预制孔径和最终成形孔径的大小等工艺参数和几何参数，探讨第一道次成形轨迹对渐进成形圆孔翻边过程的影响。

对于定曲率曲线成形轨迹，当其扫掠角度或者曲率增加时，翻边制件的厚度分布越理想，中部减薄现象可以得到明显的缓解，板料的厚度分布也越均匀；当板料厚度以及最终成形孔径增加时其成形性也越好；对于此路径而言存在一定的翻边极限即当预制孔径小到一定值时，翻边制件的壁厚分布不再能得到有效的控制，中部减薄现象较为明显。变角度定曲率曲线方案与前者有不同的特点，当其曲率一定范围内时，其成形质量处于一个较好的范围，而一旦超出这个曲率范围，成形质量便会下降；当板料厚度、最终成形孔径增大时，此路径的成形结果同前者相同，都是趋于良好；变角度定曲率曲线路径同样存在极限预制孔径。

关键词：两道次渐进成形；数值模拟、渐进成形、圆孔翻边、曲率变化、路径设计

Abstract

The metal sheet cuff process is a special sheet metal forming process, which is widely used in all sectors of the manufacturing industry. So far, the sheet metal flanging process is based on stamping die and carried out. At the same time, the mold manufacturing costs are very high, the mold production cycle is longer, so to a large extent restricted the development of the flanging process. In order to solve this problem, a new sheet forming method - sheet metal forming process is proposed. The sheet metal progressive forming process utilizes the idea of ​​"layered" manufacturing, which is deformed layer by layer by controlling the movement of the tool head. Therefore, the sheet metal forming process does not need to manufacture a specific mold, and has a large forming limit, high degree of complex parts, high processing flexibility, high flexibility and many other advantages. In this paper, we use DYNAFORM5.9 and UG10.0 computer modeling software and LS-DYNA solver, using numerical simulation of the experimental method of sheet metal forming process simulation. By analyzing the simulation results, the deformation characteristics of the round forming process of progressive forming hole are summarized. Finally, the simulation results are compared with the actual experimental results to verify the credibility of the finite element model established in the computer software.

The main contents of this paper are the numerical simulation of the two rounds of progressive forming round hole crossover process. The characteristics of two new holes in the first pass forming track with a certain curvature are discussed, and the processing path And the process parameters and geometric parameters such as the curvature of the curvature curve path, the initial thickness of the sheet and the size of the preformed aperture and the final forming aperture are discussed. The first pass forming trajectory is discussed. The influence of the process.

For the curvature forming curve, when the sweeping angle or curvature increases, the thickness of the cuff part of the distribution will be more ideal, the central thinning phenomenon can be significantly alleviated, the thickness of the sheet material distribution is more uniform; when the sheet thickness and the final forming aperture increases its formability is also better; for this path there is a certain cuff limit that when the prefabricated aperture is small enough to a certain value, the cuff part of the wall thickness distribution can no longer be effectively controlled, The central thinning phenomenon is more obvious. The variable angle curvature curve has different characteristics from the former. When its curvature is within a certain range, its forming quality is in a good range, and once the curvature range is exceeded, the forming quality will decrease. When the thickness of the sheet is final, When the aperture is increased, the forming result of this path is the same as that of the former, and it tends to be good. The variable angle curvature curve path also has the limit prefabricated aperture.

key words: Two-step incremental forming, numerical simulation, incremental forming, round hole cuff, curvature change, path design

目录

第一章 绪论 1

1.1课题的背景和意义 1

1.1.1课题背景 1

1.1.2课题意义 1

1.2渐进成形工艺介绍 2

1.2.1渐进成形工艺的定义 2

1.2.2金属板料渐进成形工艺分类 2

1.2.3金属板料渐进成形工艺的优缺点 4

1.3板料渐进成形工艺的发展现状 4

1.3.1国内外研究现状 4

1.3.2课题组研究现状 5

1.3.3渐进成形工艺的应用 6

1.4传统圆孔翻边冲压工艺介绍 6

1.4.1圆孔翻边定义 6

1.4.2圆孔翻边的类型 7

1.4.3传统圆孔翻边工艺的成形原理 7

1.5渐进成形圆孔翻边介绍 8

1.5.1渐进成形圆孔翻边原理 8

1.5.2渐进成形圆孔翻边工艺特点 8

1.5.3临界翻边系数与极限翻边系数 9

1.6课题主要内容 9

1.7本章小结 10

第二章 渐进成形圆孔翻边数值模拟研究方法 11

2.1数值模拟方法简介 11

2.1.1有限元方法介绍 11

2.1.2显式有限元方法原理 11

2.1.3有限元分析软件的选择 17

2.2有限元模型的建立与可信性验证 18

2.3圆孔翻边渐进成形实验方法 21

2.3.1渐进成形试验设备简介 21

2.3.2 金属板料选择 22

2.4单道次渐进成形模拟实验分析示例 22

2.5本章小结 23

第三章 单道次渐进成形圆孔翻边的模拟研究 24

3.1.单道次工艺参数特点 24

3.2均匀壁厚判据的建立 26

3.3单道次均匀壁厚圆孔翻边成形极限 27

3.5本章小结 28

第四章 两道次渐进成形圆孔翻边的数值模拟研究 29

4.1两道次渐进成形路径规划 29

4.1.1变角度两道次渐进成形圆孔翻边路径 29

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