摘要
在搅拌摩擦焊接过程中,工具-工件接触面的摩擦行为直接影响焊缝热输入及材料流动。因此,接触面摩擦系数的准确估算对于搅拌摩擦焊接过程建模是极其关键的。在本文中,针对双轴肩搅拌摩擦焊接过程,提出了一种计算温度相关的摩擦系数的新方法。采用耦合欧拉-拉格朗日方法(CEL)对双轴肩搅拌摩擦焊焊接铝合金过程进行了建模,同时考虑了接触面的摩擦产热、塑性变形产热及材料流动。将试验获取的接触面温度数据与模型计算得到的接触面温度数据进行匹配。设计了一套反算算法,逐步计算温度相关的接触面摩擦系数。摩擦系数随着焊接温度上升都先缓慢下降后迅速上升再迅速下降,最后缓慢下降逐步接近于零。将计算得到的与温度相关的摩擦系数与以往文献的计算结果做对比,基于修正粘着摩擦理论分析不同方法得到的摩擦系数随温度变化规律的异同。采用本文的摩擦系数建立双轴肩焊接过程的CEL模型,计算得到的接触面温度及截面焊缝形貌都与试验结果相符合。
In the process of friction stir welding(FSW),the friction behavior at the tool-workpiece interface directly affects heat input and material flow.Therefore,accurate estimation of the friction coefficient at the interface is important for modeling of the FSW process.In this paper,a new approach to calculate the temperature dependent friction coefficient is proposed for modeling the bobbin-tool friction stir welding(BT-FSW)process.At the same time,the coupled Eulerian-Lagrangian(CEL)method is used to model the BT-FSW process of an aluminum alloy,and the friction heat,plastic deformation heat and material flow are considered.The interface temperature data obtained from the experiments are matched with the interface temperature data calculated by the model.The inverse algorithm is designed to calculate the temperature dependent friction coefficient.With the increase of welding temperature,the friction coefficient first slowly decreases,then rapidly increases,and then rapidly decreases,and finally slowly decreases to close to zero.The calculated friction coefficient is compared with the calculated results of previous literatures,and the differences and similarities of the friction coefficients with temperature are analyzed based on the modified adhesive friction theory.The results show that the model established using the temperature dependent friction coefficient can accurately reproduce the BT-FSW process.
作者
胡晔晖
王宇晗
季宇雷
HU Yehui;WANG Yuhan;JI Yulei(School of Mechanical Engineering,Shanghai Jiao Tong University,Shanghai 200240,China)
出处
《机械设计与研究》
CSCD
北大核心
2024年第4期192-197,206,共7页
Machine Design And Research
