基于多参数优化的液压胀管技术研究

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3.0 牛悦 2024-11-19 4 4 2.82MB 63 页 15积分
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摘 要
液压胀管成形技术作为变截面管成形件的一种先进技术，拥有成形零件质量
轻，强度和刚度高，精度高，可减少后续组装焊接量等优点，在各领域的应用都
很广，尤其是在汽车制造产业、航空航天行业领域。液压胀管是一种较新的成形
技术，其成形原理非常复杂，国内对它的研究比较少，而且国际上也没有成熟的
理论和经验用来参考，所以对液压胀管成形技术的研究，拥有十分的重要意义。
首先，给出了液压胀管成形的工艺过程和主要工艺参数的一般计算方法，分
析了成形过程中可能出现的缺陷形式，壁厚的分布规律，各成形阶段的应力应变
状态及在屈服椭圆上的位置。
其次，运用有限元分析软件 DYNAFORM 对液压胀管成形过程进行模拟分析。
针对影响零件液压成形的内压力和轴向力的匹配关系、管件与模具之间的摩擦系
数及冲头速度等因素进行模拟与分析，得到了在不同工艺条件下工件的成形状态
和壁厚分布等规律，也分析了不同的工艺参数对工艺过程的影响。
随后，在工艺参数组合优化的问题上，首先以最大壁厚减薄率和壁厚均匀性
为考核目标，通过数值模拟和正交优化方法，对比分析不同方案下最大壁厚减薄
率和壁厚均匀性，确定了最优方案，以提高变截面管的成形性能。结果表明，轴
向压力对管件成形的影响最大，内压力次之，摩擦系数的影响最小。在此最佳方
案上，结合了 MATLAB 的神经网络工具箱和遗传算法工具箱，建立了液压胀管成
形的神经网络模型，并对直线路径和折线路径进行了组合优化。结果表明：神经
网络结合遗传算法是一种可行稳定的智能优化方法，可以解决液压成形中的工艺
参数优化问题。
对液压胀管多参数优化的研究，不仅提高了成形性能，而且为实际应用的成
形质量得到明显提高提供了理论基础，更主要为汽车轻量化行业提供了技术支持。
关键词：液压胀管 数值模拟 正交试验 神经网络 遗传算法
ABSTRACT
The hydroforming technology as an advanced technology of manufacturing hollow light
structures is now widely applied in fields of automobile and aerospace industry. The
parts formed by hydroforming technology have many advantages, such as lightweight,
less components, high rigidity, less subsequent machining time and shorter welding
assembling cycle, etc. The tube hydroforming technology is related to many factors,
among which, the loading path of the process parameters and matching relationship of
internal pressure and axial force are particularly important. So how to design the loading
paths and how to match them is the key point in practical application of hydroforming
technology.
Firstly, the tube hydroforming process and the general calculation method of main
process parameters were briefly introduced. The form of defects in the forming process,
the thickness distribution and forming stage of the stress-strain state and the position of
in the yield ellipse were analyzed.
The finite element software DYNAFORM was applied to simulate the whole tube
hydroforming process. Two main failure types in the process of hydroforming are
wrinkling and bursting. The strain distribution and thickness distribution at different
process parameters were presented. Not only friction coefficient but also the effect of
different matching of internal pressure and axial force was simulated and analyzed. In
addition, the velocity of punch was considered too.
In the process parameters on the combinatorial optimization problems, first of all,
numerical simulation was made on parameters like internal pressure and axial force as
well as friction coefficient of tube that affect the formation of variable cross-section
tube. Through numerical simulation and orthogonal optimization, the most thickness
reduction ratio and thickness uniformity on different conditions were contrasted and
analyzed. An optimum scheme was obtained and it could improve the formability of
variable cross-section tube. The result indicates that the axial force plays the most
important role on thickness reduction ratio. And then, by means of Neural Network
toolbox and Genetic Arithmetic toolbox in MATLAB, the Neural Network model of
tube hydroforming technology was built, and the optimization match of straight line and
fold line loading paths were also done. Results show that combined use of Neural
Network with Genetic Arithmetic is a stable, feasible and intelligent optimization
method, which can provide a new way to solve the process parameters optimization
problem in tube hydroforming technology.
Research on Multi-parameters optimization of tube hydroforming, not only improves
formability but also provides theoretical basis for improving forming quality in the
practical application, mainly promotes the application of tube hydroforming technology
in the lightweight car.
Key Words: Tube hydroforming process, Numerical simulation,
Orthogonal Experiment, Neural Network, Genetic
Arithmetic
目 录
中文摘要
ABSTRACT
第一章 绪 论 ...................................................................................................................1
§1.1 引言 .................................................................................................................1
§1.2 液压胀管技术和应用 .....................................................................................1
§1.2.1 液压胀管的原理 ...................................................................................1
§1.2.2 液压胀管的特点 ...................................................................................2
§1.2.3 液压胀管的应用 ...................................................................................3
§1.3 液压胀管的研究现状 ....................................................................................4
§1.3.1 国内外液压胀管技术的研究现状 .......................................................4
§1.3.2 液压胀管技术的问题 ...........................................................................5
§1.4 本课题的主要研究内容 .................................................................................5
第二章 液压胀管技术 .....................................................................................................7
§2.1 工艺过程 ..........................................................................................................7
§2.2 确定主要工艺参数 .........................................................................................8
§2.2.1 初始屈服压力 .......................................................................................8
§2.2.2 开裂压力 ...............................................................................................8
§2.2.3 整形压力 ...............................................................................................8
§2.2.4 轴向进给力 ...........................................................................................9
§2.2.5 合模力 .................................................................................................10
§2.2.6 轴向起皱临界应力 .............................................................................10
§2.2.7 补料量 .................................................................................................11
§2.3 缺陷形式以及极限膨胀率 ...........................................................................12
§2.3.1 缺陷形式 .............................................................................................12
§2.3.2 极限膨胀率 .........................................................................................12
§2.4 管件的壁厚分布规律和影响因素 ...............................................................13
§2.4.1 壁厚的分布规律 .................................................................................13
§2.4.2 厚度分界圆 .........................................................................................14
§2.5 液压胀管应力应变状态及在屈服椭圆上的位置 .......................................15
§2.5.1 初始填充阶段 .....................................................................................16
§2.5.2 成形阶段 .............................................................................................17
§2.5.3 整形阶段 .............................................................................................19
§2.6 本章小结 .......................................................................................................20
第三章 液压胀管的数值模拟与分析 ...........................................................................21
§3.1 有限元仿真模型的建立 ...............................................................................21
§3.1.1 产品建模 .............................................................................................21
§3.1.2 有限元模型的网络划分 ......................................................................21
§3.1.3 选择单元类型 .....................................................................................22
§3.1.4 确定材料参数 .....................................................................................23
§3.1.5 选择边界条件 .....................................................................................23
§3.1.6 定义求解时间和输出步数 .................................................................23
§3.2 影响液压胀管性能的主要因素 ...................................................................24
§3.2.1 内压力与轴向压力的匹配关系影响 ..................................................24
§3.2.2 管件和模具之间摩擦系数对成形质量的影响 .................................28
§3.2.3 冲头速度大小对成形质量的影响 .....................................................29
§3.3 本章小结 .......................................................................................................31
第四章 基于正交试验的液压胀管多工艺参数优化 ...................................................32
§4.1 正交试验 .......................................................................................................32
§4.2 正交试验结果的分析方法 ...........................................................................32
§4.3 液压胀管的正交设计试验 ...........................................................................33
§4.4 分析试验结果 ...............................................................................................34
§4.5 本章小结 .......................................................................................................39
第五章 液压胀管工艺参数的优化 ...............................................................................40
§5.1 人工神经网络 ...............................................................................................40
§5.2 遗传算法（GA）.........................................................................................43
§5.3 液压胀管多参数的优化 ...............................................................................45
§5.3.1 优化思路 .............................................................................................45
§5.3.2 选择汇编语言 .....................................................................................46
§5.3.3 建立神经网络的模型 .........................................................................47
§5.3.4 确定遗传算法的目标函数 .................................................................48
§5.3.5 归一化处理输入输出向量 ...............................................................49
§5.3.6 神经网络和遗传算法的优化程序 .....................................................49
§5.3.7 讨论优化结果 .....................................................................................50
§5.4 本章小结 .......................................................................................................52
第六章 结论与展望 .......................................................................................................53
§6.1 结论 ................................................................................................................53
§6.2 展望 ................................................................................................................54
参考文献 .........................................................................................................................55
在读期间公开发表的论文和承担科研项目及取得成果 .............................................58
致 谢 ...............................................................................................................................59
摘要：

摘要液压胀管成形技术作为变截面管成形件的一种先进技术，拥有成形零件质量轻，强度和刚度高，精度高，可减少后续组装焊接量等优点，在各领域的应用都很广，尤其是在汽车制造产业、航空航天行业领域。液压胀管是一种较新的成形技术，其成形原理非常复杂，国内对它的研究比较少，而且国际上也没有成熟的理论和经验用来参考，所以对液压胀管成形技术的研究，拥有十分的重要意义。首先，给出了液压胀管成形的工艺过程和主要工艺参数的一般计算方法，分析了成形过程中可能出现的缺陷形式，壁厚的分布规律，各成形阶段的应力应变状态及在屈服椭圆上的位置。其次，运用有限元分析软件DYNAFORM对液压胀管成形过程进行模拟分析。针对影响零件液压...

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作者：牛悦 分类：高等教育资料 价格：15积分 属性：63 页 大小：2.82MB 格式：PDF 时间：2024-11-19

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