Numerical modeling for the effect of pin profiles on thermal and material flow characteristics in friction stir welding
Numerical modeling for the effect of pin profiles on thermal and material flow characteristics in friction stir welding
复制标题
搅拌摩擦焊中销轮廓对热和材料流动特性影响的数值模拟
DOI：
10.1016/j.matdes.2015.04.012
复制
发表时间：
2015-07-15
影响因子：
8.4
通讯作者：
Rethmeier, Michael
中科院分区：
文献类型：
--
作者：
Su, Hao;Wu, Chuan Song;Rethmeier, Michael
了解搅拌头形状对搅拌摩擦焊接过程中的热行为和材料流动行为的影响，对于基于科学原理的搅拌头优化设计具有重要意义。采用基于计算流体力学的数值方法，对两种不同形状搅拌头（轴对称锥形搅拌头和非对称三平板搅拌头）搅拌摩擦焊过程中的热物理现象进行了定量分析。通过将稳态模型和瞬态模型相结合，既保证了计算效率，又保证了计算精度。考虑了刀具-工件接触面的局部粘着/滑动接触条件，确定了热传导和材料流动的边界条件。阐述了三平面工具焊接过程中的总生热量、热密度和温度分布，并与锥形工具进行了比较，详细描述了不同钉头方位下的材料流动形态和变形区域。通过焊接宏观形貌的观察，发现三平面刀具的变形区大于锥形刀具的变形区。计算的热循环和某些位置的峰值温度值与实验测量值吻合良好。(C)2015爱思唯尔有限公司版权所有。
Understanding the influence of tool/pin shapes on the thermal and material flow behaviors in friction stir welding is of great significance for the optimal design of tool/pin based on a scientific principle. In this study, a numerical method based on computational fluid dynamics is employed to quantitatively analyze the thermo-physical phenomena in friction stir welding with two tools of different pin shapes (axisymmetrical conical tool and asymmetrical triflat tool). Through combining a steady state model with a transient state model, both the computation efficiency and accuracy are ensured. The boundary conditions of heat transfer and material flow are determined with considering a partial sticking/sliding contact condition at the tool-workpiece interface. The total heat generation, heat density and temperature distribution during the welding process with triflat tool are elucidated and compared with that of conical tool, and the material flow patterns and deformation regions of various pin orientations are illustrated in detail. It is found that the deformation zone caused by triflat tool is larger than that by conical tool, which is validated by the weld macrographs. The computed thermal cycles and peak temperature values at some locations are in good agreement with the experimentally measured ones. (C) 2015 Elsevier Ltd. All rights reserved.