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A study on warm hydroforming of lightweight sheet materials: Process optimization.

机译：轻质板材的热液压成形研究：工艺优化。

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摘要

Lightweight materials such as aluminum and magnesium alloys have been considered to replace ferrous automotive components to reduce fuel consumption and hazardous emissions in transportation vehicles. Warm hydroforming technology, as an emerging hybrid process, was investigated to enable high formability, reduced process steps and part consolidation for auto body and structure parts where mass reduction opportunities exist. For successful and cost effective implementation of the warm hydroforming process, selective heating of dies and blank is necessary in addition to careful design and control of loading parameters including hydraulic pressure, blank holder force and punch speed. In this study, a novel methodology to control the process variables was developed under warm hydroforming conditions. Depending on the response characteristics on the deformation, the process variables could be controlled spatially and/or temporally. First, the temperature distribution could be determined spatially through the adaptive isothermal FEA/DOE approach. The combined adaptive isothermal FEA and DOE approach could accurately provide the basic and critical guidelines in determining the optimal temperature distribution for a given part, tooling, hydraulic medium and blank material. The developed hybrid approach could further reduce the total analysis time to predict the optimal temperature condition of the tooling regions.{09}Secondly, temporal loading profiles of hydraulic pressure, blank holder force and punch speed could be determined by the adaptive FEA with fuzzy control algorithm. The adaptive FEA with fuzzy control algorithm could predict the loading profile rapidly requiring only a single simulation with few runs for fine tuning. Finally, to broaden basic understandings and rapidly provide the process windows of warm HMD (hydromechanical deep drawing) process, a simple analytic model under warm HMD condition was developed.{09}The floating/non-floating conditions which affect the formability could be determined by a simple pressure vessel theory. A failure criterion was also developed and could predict the failure/success of the forming process. The developed methodologies, numerical tools/modules and analytic models could broaden the general understanding and use of sheet hydroforming towards achievement of lightweight parts and structures.
机译：人们已经考虑使用轻质材料（例如铝和镁合金）替代黑色汽车部件，以减少运输车辆中的燃料消耗和有害排放。研究了暖液压成形技术作为一种新兴的混合工艺，以实现具有较高质量降低机会的车身和结构零件的高成形性，减少的工艺步骤和零件固结。为了成功且经济高效地实施热成型工艺，除了精心设计和控制包括液压，毛坯夹持力和冲头速度在内的加载参数外，还必须对模具和毛坯进行选择性加热。在这项研究中，开发了一种在温暖的液压成形条件下控制过程变量的新颖方法。根据变形的响应特性，可以在空间和/或时间上控制过程变量。首先，可以通过自适应等温FEA / DOE方法在空间上确定温度分布。自适应等温FEA和DOE的组合方法可以准确地为确定给定零件，工具，液压介质和毛坯材料的最佳温度分布提供基本和关键指导。发展起来的混合方法可以进一步减少总的分析时间，以预测模具区域的最佳温度条件。{09}其次，可以通过模糊控制的自适应有限元分析确定液压，毛坯夹持器力和冲头速度的时间载荷曲线算法。具有模糊控制算法的自适应FEA可以快速预测负载曲线，仅需进行一次仿真即可进行微调。最后，为拓宽基本理解并迅速提供温热HMD（液压机械深冲）过程的过程窗口，开发了在温热HMD条件下的简单分析模型。{09}可以确定影响成形性的浮动/非浮动条件通过简单的压力容器理论。还制定了失效准则，该准则可以预测成形过程的失败/成功程度。所开发的方法，数值工具/模块和分析模型可以拓宽对液压成形的一般理解和使用，从而实现轻量化的零件和结构。

著录项

  • 作者

    Choi, Ho.;

  • 作者单位

    University of Michigan.;

  • 授予单位 University of Michigan.;
  • 学科 Engineering Mechanical.
  • 学位 Ph.D.
  • 年度 2006
  • 页码 159 p.
  • 总页数 159
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 机械、仪表工业;
  • 关键词

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