Understanding process force transients with application towards defect detection during friction stir welding of aluminum alloys
Understanding process force transients with application towards defect detection during friction stir welding of aluminum alloys
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DOI：
10.1016/j.jmapro.2020.03.003
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发表时间：
2020-06-01
影响因子：
6.2
通讯作者：
Pfefferkorn, Frank E.
中科院分区：
文献类型：
--
作者：
Franke, Daniel;Rudraraju, Shiva;Pfefferkorn, Frank E.
搅拌摩擦焊过程中表面下缺陷的形成限制了该工艺在大批量生产中的应用。通过开发基于测量的过程输出的过程中缺陷检测方法，存在消除/减少对这种缺陷的昂贵的焊后检查的需要的可能性。目前的状态，过程中的缺陷检测主要包括应用“黑盒”的方法，相关的过程输出的缺陷发生没有一个基本的物理理解是什么产生的变化的输出。当改变摩擦搅拌焊接工艺的任何方面时，这种方法限制了这种方法的应用。目前的研究旨在提供一个基本的物理解释是什么驱动搅拌摩擦焊工艺力的振荡在工具的旋转频率，以及发生什么时，工具与缺陷和振荡的过程力被改变。一个新的理解，使通过同步的力测量与角位置测量的工具功能。结果表明，偏心运动的工具和/或倾斜的肩部表面的旋转是过程力振荡的主要驱动因素。已经提出了一个基本的解释之间的相互作用的工具探头和有缺陷的卷的功能。物理理解有助于解释改变过程将如何改变检测方法所基于的力瞬变，这将实现更鲁棒和可转移的方法。
The formation of sub-surface defects during friction stir welding has limited the adoption of the process in high volume production. A potential exists to eliminate/reduce the need for costly post weld inspection of such defects through the development of an in-process defect detection method based on a measured process output. The current state of in-process defect detection consists primarily of applying "black box" methods of correlating process outputs to defect occurrence without a fundamental physical understanding of what is producing the change in the output. This approach constrains the application of such methods when altering any aspect of the friction stir welding process. The current study seeks to provide a fundamental physical explanation as to what is driving the oscillation of friction stir welding process forces at the tool rotational frequency, as well as what is occurring when the tool interacts with defects and the oscillatory process forces are altered. A novel understanding was enabled through the synchronization of force measurements with angular position measurements of tool features. The results suggest that the eccentric motion of the tool and/or the rotation of a slanted shoulder surface are the primary drivers of process force oscillations. A fundamental explanation of the interaction between features on the tool probe and defective volumes has been proposed. The physical understanding helps to explain how altering the process will alter the force transients on which the detection method is based, which will enable a more robust and transferable method.