卡车顶盖论文：中型卡车顶盖冲压成形数值模拟分析及其优化.doc

卡车顶盖论文：中型卡车顶盖冲压成形数值模拟分析及其优化【中文摘要】汽车整车的开发周期主要取决于其覆盖件。由于汽车覆盖件结构复杂、制造精度及表面质量要求极高,且其成形受很多因素的影响,仅靠工程师的设计经验及传统的“试错法”很难获得高质量的产品,且开发周期长成本高。因此,应用数值模拟及优化技术对提高产品的设计质量、缩短汽车的研制周期、降低生产成本、增强产品的市场竞争力等方面有着非凡的意义。本文以某中型卡车顶盖为例,通过数值模拟及优化技术,探讨其在成形过程中有可能会出现的质量缺陷及解决方法,确定该顶盖最优的模具结构及成形工艺为实际生产提供指导。本文基于板料成形基础理论、冲压数值模拟及优化技术,首先应用DYNAFORM软件对顶盖进行冲压成形的拉延、修边及其回弹的数值模拟,分析了其板料的变形特点并研究了成形过程中有可能会出现的质量问题及相关参数的影响(模具间隙、摩擦系数、压边力及拉延筋阻力)；然后,本文建立了成形质量的多目标模型并通过有限元模拟获得了相应的正交试验样本,并在MATLAB软件的环境下设计一个BP神经网络建立了各因素与成形质量目标函数间的非线性映射关系,并运用多目标遗传算法进行工艺参数优化,确定一组最优解集并在DYNAFORM中验证；最后,本文基于上述工作模拟了顶盖的翻边工序及其回弹,利用正交优化获得了相对最优参数组合,并将此结果进行了实验验证。通过数值模拟与试验对比分析发现：数值模拟技术能预测成形缺陷,应用正交设计及MATLAB优化技术获得的成形最优工艺参数组合较为准确,可以供生产实践作为参考。该技术路线不仅显著提高了工作效率,降低了生产成本,同时也提高了产品的质量,值得在该领域推广应用。【英文摘要】The development cycle of a new type car mainly lies on its auto panels. It is very difficult to obtain high quality products only with empirical formula and traditional “trial and error method” due to the complex auto panels, rigid manufacturer precision and surface quality of the auto panels and a lot of factors affecting its stamping forming process, in addition, the development cycle is long and its costs is very high. Therefore, the auto panels stamping forming simulation technology has vital significance in cutting down auto manufacturing circle, reducing cost, improving design quality and enhancing market competitive ability.In this paper, taken a medium trucks roof panel for example, some researches in studying its quality problems and solutions during the roof panels forming process was done by numerical simulation and optimization technology, and the best forming conditions which has reference significance to the actual production was selected out.Based on the basal theory of sheet metal forming, simulation technology and optimization technology was researched in this paper. Firstly, using numerical simulation in drawing forming and trimming process and its spring-back, a medium trucks roof panel was taken into account to obtain the deformation characteristics of the blank and study the quality problems that may appear in the forming process and the impact of the parameters (gap between die and punch, friction modulus, blank holder force and draw-bead resistance); Secondly, this paper set up a multi-objective model between its impact factors and forming quality and obtained corresponding orthogonal samples by finite element method. It also built a non-linear mapping between its impact factors and forming quality by designing a BP neural network in MATLAB software, and then obtained an optimized set of impact factors in the forming process by multi-objective genetic algorithm; Finally, based on the above work, the numerical simulation in flanging process and its spring-back was researched, and the optimized parameter combination was determined by orthogonal experiment and the results was verified at last.The results by contrast show that numerical simulation can forecast the forming defects, and the optimized parameter combination obtained by orthogonal experiment and MATLAB optimization technology is exact. The optimization results can guide the actrol production. The technology course can not only increase the work efficiency greatly and reduce the production costs but also improve the quality of products, the popularization and application of which in this field is worthy.【关键词】卡车顶盖 数值模拟 神经网络 遗传算法 参数优化【英文关键词】roof panel numerical simulation artificial neural network genetic algorithm parameters optimization【目录】中型卡车顶盖冲压成形数值模拟分析及其优化摘要3-4ABSTRACT4-5第一章 绪论10-17引言101.1 课题的研究背景及意义10-111.2 覆盖件冲压成形中失效形式及原因11-121.2.1 起皱111.2.2 破裂11-121.2.3 回弹121.3 覆盖件冲压成形中数值模拟与工艺优化技术发展现状12-151.3.1 国内数值模拟与优化技术发展现状12-131.3.2 国外数值模拟与优化技术发展现状13-151.4 本文研究的主要内容15-17第二章 汽车覆盖件冲压成形理论基础17-25引言172.1 冲压变形时的应力与应变状态17-202.1.1 冲压变形时的应力状态17-192.1.2 冲压变形时的应变状态19-202.2 塑性条件20-222.2.1 屈雷斯卡屈服准则202.2.2 Von.Mises塑性条件20-212.2.3 Hill塑性条件21-222.3 冲压变形成形极限及变形倾向性与控制222.4 汽车覆盖件的特点22-252.4.1 汽车覆盖件的质量要求22-232.4.2 汽车覆盖件的结构特点232.4.3 汽车覆盖件的成形特点23-25第三章 基于DYNAFORM的顶盖拉延成形数值模拟与优化25-383.1 基于DYNAFORM的板料成形数值模拟流程25-263.2 顶盖拉延成形数值模拟26-333.2.1 3D造型与初步工艺分析263.2.2 工艺补充及压料面设计26-273.2.3 有限元模型建立27-283.2.4 冲压方向的调整28-303.2.5 边界条件的确定303.2.6 坯料估算30-313.2.7 成形工艺参数的确定31-333.3 顶盖拉延成形模拟结果分析及优化33-373.4 小结37-38第四章 基于DYNAFORM的顶盖修边及回弹模拟38-454.1 顶盖修边模拟38-394.2 回弹模拟理论基础39-414.2.1 影响回弹的主要因素39-404.2.2 回弹数值模拟算法40-414.2.3 DYNAFORM软件中两种常用的回弹分析方法414.3 顶盖修边回弹数值模拟41-434.3.1 DYNAIN文件导入41-424.3.2 坯料定义424.3.3 边界条件设定424.3.4 其他相关参数的设置42-434.4 顶盖修边回弹结果分析43-444.5 小结44-45第五章 基于正交设计及MATLAB的多目标预测与工艺优化45-655.1 正交试验设计原理及过程45-475.1.1 正交试验设计原理45-465.1.2 正交试验设计过程46-475.2 顶盖修边及其回弹正交试验47-505.2.1 试验指标的确定475.2.2 影响因素及水平的确定47-485.2.3 正交表的选取及顶盖正交试验48-505.3 人工神经网络概述50-525.3.1 人工神经网络的基本原理50-515.3.2 人工神经网络特性51-525.4 顶盖BP神经网络预测模型的建立52-575.4.1 MATLAB神经网络工具箱52-535.4.2 学习样本的获取及处理53-545.4.3 神经网络的设计54-555.4.4 神经网络的训练与测试55-575.5 遗传算法57-595.5.1 遗传算法的核心内容57-585.5.2 遗传算法的应用流程58-595.6 顶盖的多目标遗传优化59-605.6.1 MATLAB遗传算法工具箱的调用595.6.2 遗传算法寻优过程及结果59-605.7 优化结果的验证60-645.8 小结64-65第六章 基于DYNAFORM的顶盖侧翻边及其回弹模拟65-736.1 顶盖侧翻边成形模拟65-706.1.1 翻边成形概述656.1.2 侧翻边成形模拟的过程65-676.1.3 侧翻边模拟结果分析67-706.2 顶盖侧翻边回弹模拟70-726.2.1 翻边回弹概述706.2.2 侧翻边回弹模拟过程70-716.2.3 侧翻边回弹模拟结果分析71-726.3 小结72-73第