Hydroforming of Aluminum Tubes for Automotive Applications

汽车应用铝管液压成形

• 批准号: 0140599
• 负责人: Stelios Kyriakides
• 金额: $ 29.98万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-06-01 至 2006-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0140599&HistoricalAwards=false
• 关键词: Hydroforming; Aluminum; Tubes; Automotive; Applications

Hydroforming is a relatively new process for shaping tubular components out of metals. A simple tube can be hydroformed into a fairly complex shape suitable for use as a frame for a structural component. A tube is placed between two half dies and then pressurized internally. It expands, comes into contact with the dies and is forced to conform to their shape. The simple radial expansion of the tube can lead to a number of defects, with a major concern being thinning of the expanded wall. This can lead to tube burst. In order to reduce thinning, the burst strain can be increased by axially feeding undeformed material into the dies from the two ends using actuators. However, the extent of the developed axial compression in limited by buckling and wrinkling and by friction. Thus, for every part, a working envelope in the axial feed-pressure plane must be established which is free of these modes of failure. While aluminum in tube form is ideal for hydroforming, it is less ductile than steel and has more complex constitutive behavior, which make the hydroforming working envelope tighter. This need for a better understanding of processing control coupled with the empirical manner in which the dies and the process have been designed, have not allowed wide use of hydroforming for aluminum components. The objective of this three-year project is to develop a scientific basis for establishing the working envelopes of the process parameters. The problem will be tackled in a three prong manner consisting of hydroforming experiments, development of constitutive models for appropriate aluminum alloy extruded tubes, and development of several levels of numerical models for analyzing hydroforming and establishing its limits. An important component of the project is a custom hydroforming facility, which will be fabricated and used to study the process parametrically. Alcoa and GM will be act as industrial partners to the project and will interact with graduate and undergraduate students on a regular basis.

液压成形是一种相对较新的工艺，用于将金属制成管状部件。一个简单的管可以液压成形为一个相当复杂的形状，适用于作为一个框架的结构部件。管被放置在两个半模之间，然后内部加压。它膨胀，与模具接触，并被迫符合它们的形状。管的简单径向膨胀可导致许多缺陷，主要问题是膨胀壁变薄。这可能导致管路爆裂。为了减少减薄，可以通过使用致动器从两端将未变形的材料轴向进给到模具中来增加破裂应变。然而，轴向压缩的发展程度受到屈曲和摩擦的限制。 因此，对于每一个部件，必须在轴向进给压力平面内建立一个没有这些失效模式的工作包线。铝合金管材是理想的内高压成形材料，但其塑性较钢差，本构关系复杂，使内高压成形的工作包络线更紧。这种对加工控制的更好理解的需要，加上模具和工艺设计的经验方式，不允许铝部件液压成形的广泛使用。这一为期三年的项目的目标是为确定工艺参数的工作范围奠定科学基础。这个问题将被解决在一个三管齐下的方式，包括液压成形实验，适当的铝合金挤压管的本构模型的发展，和几个层次的数值模型的发展，用于分析液压成形，并建立其限制。该项目的一个重要组成部分是一个自定义的液压成形设施，这将是制造和用于研究参数化的过程。美铝和通用汽车将作为该项目的工业合作伙伴，并将定期与研究生和本科生互动。