Experimental investigation and FE simulation of ductile fracture of aluminium alloy laser welded butt joints

铝合金激光焊接对接接头延性断裂的实验研究与有限元模拟

• 批准号: 234633486
• 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: 2013
• 资助国家: 德国
• 起止时间: 2012-12-31 至 2014-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/234633486?language=en
• 关键词: Experimental; investigation; FE; simulation; ductile

In this project, the Rousselier model is adopted to study the crack growth of an Al6061 laser welded butt joint. Based on hardness tests across the welded joint, three different weld regions are defined, i.e. the base material (BM), the fusion zone (FZ) and the heat affected zone (HAZ). Local mechanical properties are derived from tensile test results of flat specimens extracted from these weld regions. Metallographic investigations are performed on BM, FZ and HAZ, respectively, to obtain size, shape and frequency distribution of non-metallic inclusions. The object grading technique (ARAMIS) is used to capture the deformations at the surface of flat specimens with the weld seam located in the centre. The numerical work is divided into three parts: The first activity is to calibrate the Rousselier parameters based on metallographic investigations and tensile test results of notched round bars. The second activity is to predict ductile crack growth in compact tension (C(T)) specimens and to derive the corresponding stress and strain levels of flat specimens during the tensile process by applying the same Rousselier parameters obtained in the first part. The third activity is to predict the final fracture of transverse flat specimens including Lüders band propagation. The aim is to apply the Rousselier model taking Lüders band propagation into account to describe ductile fracture, to predict the mechanical behaviour of laser welded joints reliably and to improve the design of laser weldments.

本项目采用Rousselier模型研究Al6061激光焊接对接接头的裂纹扩展。根据焊接接头的硬度测试，定义了三个不同的焊接区域，即母材 (BM)、熔合区 (FZ) 和热影响区 (HAZ)。局部机械性能源自从这些焊缝区域提取的扁平样品的拉伸试验结果。分别对BM、FZ和HAZ进行金相研究，以获得非金属夹杂物的尺寸、形状和频率分布。对象分级技术 (ARAMIS) 用于捕获焊缝位于中心的扁平样品表面的变形。数值工作分为三个部分：第一个活动是根据缺口圆钢的金相研究和拉伸试验结果校准鲁塞尔参数。第二项活动是预测致密拉伸 (C(T)) 样本中的延性裂纹扩展，并通过应用第一部分中获得的相同鲁塞尔参数来推导平板样本在拉伸过程中相应的应力和应变水平。第三项活动是预测横向扁平样本的最终断裂，包括吕德斯带传播。目的是应用考虑了 Lüders 带传播的 Rousselier 模型来描述延性断裂，可靠地预测激光焊接接头的机械行为并改进激光焊件的设计。