Stretch Forming of Aluminum Extruded Tubes for Automotive Applications

汽车应用铝挤压管的拉伸成型

• 批准号: 9734947
• 负责人: Stelios Kyriakides
• 金额: $ 16.88万
• 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: 1998
• 资助国家: 美国
• 起止时间: 1998-04-15 至 2001-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9734947&HistoricalAwards=false
• 关键词: Stretch; Forming; Aluminum; Extruded; Tubes

DMI-9734947 Kyriakides The space frame is the preferred design concept for all-aluminum light-weight cars. It is made of extruded tubes that are stretch formed to the required shape and joined by nodes. Automated assembly requires unusually tight dimensional tolerances on the formed tubes. To achieve these, the hollow extrusions are prestretched and bent to the required shapes over dies. An unwanted byproduct of this process is distortion of their cross section. Tension applied during bending over a mandrel aggravates such cross sectional distortions. To reduce this unwanted deformation, the parts are internally pressurized. At the present, the design parameters for each part (i.e. die shape, prestretch load, level of internal pressure) are selected empirically which is both costly and slow. This two-year project will use a combination of experiment and analysis to study the stretch forming process, understand the factors that govern it, and develop methods for optimizing it. The project is a joint venture between Industry (Alcoa) and University (UT-Austin). The experiments will be conducted in a custom bend-stretch-pressure forming facility recently developed. The three axes of loading have closed-loop control that allows operation of the facility via a computer. Custom nonlinear analyses have been developed which are capable of predicting the cross sectional changes of rectangular tubes bent over a rigid surface while being stretched and internally pressurized. This work will involve the use of the test facility along with the analyses to understand and optimize this manufacturing process on more general shapes.

DMI-9734947 Kyriakides空间框架是全铝轻重量汽车的首选设计概念。它是由挤出的管子制成的，该管子被拉伸至所需的形状并由节点连接。自动组件需要在形成的管子上异常紧密的尺寸公差。为了实现这些目标，空心的挤出物被置于模具上所需的形状。该过程的不良副产品是其横截面的扭曲。弯曲期间施加的张力会加剧此类横截面扭曲。为了减少这种不需要的变形，这些零件内部加压。目前，从经验上选择每个部分的设计参数（即模状，prestretch负载，内部压力水平），这既昂贵又慢。 这个为期两年的项目将使用实验和分析的组合来研究拉伸形成过程，了解支配该过程的因素，并开发优化它的方法。该项目是行业（ALCOA）和大学（UT-Austin）之间的合资企业。实验将在最近开发的自定义弯曲 - 拉伸压力形成设施中进行。加载的三个轴具有闭环控制，该控制允许通过计算机操作设施。已经开发了自定义的非线性分析，该分析能够预测矩形管的横截面变化，同时伸展和内部加压，同时弯曲。这项工作将涉及使用测试设施以及分析以了解和优化更一般形状的制造过程。