Joining by dieless hydroforming with outer pressurization

通过外部加压无模液压成形连接

基本信息

批准号：
350070123
负责人：
Professor Dr.-Ing. A. Erman Tekkaya
金额：
--
依托单位：
Institut für Umformtechnik und Leichtbau (IUL)
依托单位国家：
德国
项目类别：
Research Grants (Transfer Project)
财政年份：
2017
资助国家：
德国
起止时间：
2016-12-31 至 2019-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/350070123?language=en
关键词：
Joining dieless hydroforming outer pressurization

项目摘要

Lightweight construction requires weight optimization of structures and components. This is often realized by the integration of functions or the combination of different material properties in one single component. Due to the high diversity of material properties there are high demands on the joining technology which lead to technological or economic limits of conventional joining processes.A suitable alternative to conventional methods is the process of joining by die-less hydroforming. This process allows the production of interference fit and/or form fit joints, which makes it suitable for joining mixed compounds. By recording the pressure data of the working media it is easily possible to monitor the process which qualifies it for process automation. At present, the application range is limited by the inner accessibility. The project aims at extending the process limits by reversing the forming direction to join parts with limited inner accessibility like strongly curved or especially long profiles and also to seal rotationally symmetric containers. Instead of a radial expansion by internal high pressure there is a radial compression by external pressure. Potentially, this leads to an increase of the application range and promotes the industrial acceptance of the technology. To achieve the project objective, it is necessary - to develop tool concepts for the reliable pressurization and- to generate approaches for joint and process design.A first prototype tool was developed and used for feasibility investigations at the Institute of Forming Technology and Lightweight Construction. A static seal system was used, with the workpiece tolerance negatively affecting the sealing effect or leading to high sealing wear because of increased preload forces. Consequently, the tool technology has to be improved by using numerical and experimental investigations. The stress and strain distributions in the joining partners differ at different joining directions. Since they influence the bond strength, their determination is essential for the derivation of approaches and guidelines for process and joint design. A final comparison of the processes (with external and internal high-pressure initiation) shows the respective economy and allows to define an overall process window. The knowledge will be transferred to industrial practice by process application to demonstration parts of the cooperation partners. Finally, the project provides an industrially proven, flexible joining by forming process suitable for interference and/or form fit joints with different material combinations and external accessibility.

轻量级结构需要优化结构和组件的重量。这通常是通过函数的整合或一个单个组件中不同材料特性的组合来实现的。由于材料属性的高度多样性，对连接技术的需求很高，这导致了传统加入过程的技术或经济限制。常规方法的合适替代方案是通过无模型的水力发像加入的过程。此过程允许产生干扰拟合和/或形式拟合接头，这使其适合连接混合化合物。通过记录工作媒体的压力数据，可以很容易地监视该过程有资格进行过程自动化。目前，应用范围受内部可访问性的限制。该项目旨在通过逆转形成方向加入内部可访问性（例如强弯曲或尤其是长轮廓）以及密封旋转对称的容器，以扩展过程限制。内部高压不是径向扩展，而是通过外部压力压缩。有可能导致应用范围的增加，并促进了技术的工业接受。为了实现项目目标，有必要 - 为可靠的加压和 - 生成关节和过程设计的方法开发工具概念。开发了第一个原型工具，并用于成立技术和轻量级构建研究所的可行性调查。使用了静态密封系统，由于预紧力增加，工件公差会对密封效果产生负面影响或导致高密封磨损。因此，必须通过使用数值和实验研究来改进工具技术。联合合作伙伴中的压力和压力分布在不同的联接方向上有所不同。由于它们会影响纽带强度，因此他们的决心对于推导方法和过程和关节设计指南至关重要。该过程（与外部和内部高压启动）的最终比较显示了各自的经济，并允许定义整个过程窗口。知识将通过流程应用将其转移到工业实践中，以演示合作伙伴的部分。最后，该项目通过形成适合干扰和/或形式适合接头的工业验证，灵活的连接，具有不同的材料组合和外部可访问性。