权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Development of an experimentally supported Friction Stir Welding model for predicting the strength of dissimilar joints based on the example of aluminum-steel joints

基于铝钢接头示例，开发实验支持的搅拌摩擦焊接模型，用于预测异种接头的强度

基本信息

批准号：
318360086
负责人：
Professor Dr. Siegfried Schmauder
金额：
--
依托单位：
Institut für Materialprüfung, Werkstoffkunde und Festigkeitslehre (IMWF)
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2017
资助国家：
德国
起止时间：
2016-12-31 至 2020-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/318360086?language=en
关键词：
Development experimentally supported Friction Stir

项目摘要

Friction stir welding is a special case of friction welding where no relative movement between the joining partners is used. A rotating welding tool plunges into the joining partners and is moved along the joint line. The rotation of the tool causes the material to heat, plastify and move behind the tool creating the weld seam. The strength of the weld seam is particularly dependent on its geometry and the thermomechanical treatment of the materials during the friction stir welding process. For joints between similar materials there are a number of numerical process models.However, there is no process model for the friction stir welding process of dissimilar joints.Therefore, the strength properties of dissimilar joints can merely be determined by experiments.The aim of this project is the development of a simulation model to predict the strength properties of friction stir welded joints of different metals depending on the welding parameters. The model is developed at the example of the technically relevant material combination aluminum-steel. To accomplish this aim, a three divided procedure is applied. To validate the results of the single steps reference welds are used.In the first step, the so called process model, the friction stir welding process is continuum mechanically simulated using strain, strain-rate and temperature dependent material models. In order to deal with the very large deformations and to treat the interaction of different materials as a multiphase problem, complex computation methods have to be used. The results of the process model - weld seam geometry as well as the time dependent temperature and strain fields of both materials - are used as input for the following two steps. The results of the process model are validated by micrographs and temperature measurements.In the subsequent step a damage mechanics model is adapted, to describe the relation between thermomechanical treatment of the materials during friction stir welding, the resulting changes in microstructure, the yield strength and the damage mechanical parameters. Based on the results of the process model areas of similar thermomechanical treatment are identified in the reference weld seam. From these areas samples are taken and tested for calibrating the damage mechanics model.In the last step, the results of both preceding steps are merged into a strength model of the weld seam. The failure behavior of the weld seam resulting from the process model is determined by the damage mechanics model. The numerically determined strength properties of the joint are validated by experimental tensile tests.With the assembly of the three steps, it is possible to predict the geometry and the strength properties of dissimilar joints starting from the process input variables of the friction stir welding process.

搅拌摩擦焊是摩擦焊的一种特殊情况，在这种情况下，连接伙伴之间不使用相对运动。旋转的焊接工具插入到连接伙伴中并沿着连接线移动。工具的旋转使材料受热、塑化并在工具后面移动，从而形成焊缝。在搅拌摩擦焊接过程中，焊缝的强度特别取决于其几何形状和材料的热处理。对于相似材料之间的连接，有许多数值过程模型。然而，对于异种接头的搅拌摩擦焊接，目前还没有相应的过程模型。因此，不同节点的强度特性只能通过试验来确定。本项目的目的是开发一个模拟模型来预测不同金属搅拌摩擦焊接接头的强度特性，这取决于焊接参数。以技术相关的铝-钢组合材料为例，建立了该模型。为了达到这一目的，采用了一个分为三部分的程序。为了验证单步骤的结果，使用了参考焊缝。在第一步，所谓的过程模型，搅拌摩擦焊接过程是连续力学模拟使用应变，应变率和温度相关的材料模型。为了处理非常大的变形，并将不同材料的相互作用视为多相问题，必须使用复杂的计算方法。过程模型的结果-焊缝几何形状以及两种材料的随时间变化的温度和应变场-被用作以下两个步骤的输入。通过显微照片和温度测量验证了过程模型的结果。在接下来的步骤中，采用损伤力学模型来描述搅拌摩擦焊接过程中材料的热处理与由此产生的显微组织变化、屈服强度和损伤力学参数之间的关系。根据工艺模型的结果，在参考焊缝中识别出相似的热处理区域。从这些区域取样并测试以校准损伤力学模型。最后一步，将前两步的结果合并成焊缝的强度模型。由过程模型导致的焊缝破坏行为由损伤力学模型决定。通过实验拉伸试验验证了数值确定的接头强度特性。通过这三个步骤的组合，可以从搅拌摩擦焊接过程的工艺输入变量出发，预测不同接头的几何形状和强度特性。