FSW Joint Inserts for Closed-Cell Weld Support
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Solution Overview
Problem
Friction stir welding of closed cell structures often results in joints with inadequate support, leading to plastic deformation and less than desired properties such as strength and ductility due to the lack of support during the welding process.
Innovation Solution
Incorporating an insert within the interior portions of the workpieces that extends between and abuts the opposed interior walls, providing structural support during friction stir welding and potentially being joined to the workpieces, thereby reducing plastic deformation and enhancing weld properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If friction stir welding is performed on closed cell structures without inserts, then the welding process can be completed, but the joints lack adequate support leading to plastic deformation and reduced weld properties
Solution Approach 1:
An insert is introduced as an intermediary component between the FSW tool and the workpiece. The insert provides mechanical support to the joint region during welding, preventing plastic deformation of the closed cell structure while enabling the FSW process to proceed. The insert acts as a mediator that transfers and distributes the welding forces, improving both weld strength and joint reliability.
Solution Approach 2:
The insert is positioned and secured in the joint region before the friction stir welding process begins. This preliminary placement ensures that the support structure is in place to prevent deformation during the high-force welding operation, addressing the reliability issue before the welding forces are applied.
2Strength
If high contact loads are applied during friction stir welding to ensure quality robust welds, then weld strength is improved, but plastic deformation occurs in closed cell structures due to inadequate joint support
Solution Approach 1:
The insert serves as a mediator that allows high contact loads to be applied during FSW while distributing these forces in a manner that prevents plastic deformation of the workpiece. The insert absorbs and redistributes the welding forces, maintaining dimensional accuracy while still enabling robust weld formation.
Solution Approach 2:
The insert is positioned in advance to cushion and absorb the high contact loads that will be applied during welding. This beforehand cushioning prevents the workpiece from undergoing plastic deformation by providing a compliant yet supportive interface between the FSW tool and the closed cell structure.
3Manufacturing precision
If inserts are added to provide support during friction stir welding, then weld properties and dimensional accuracy are improved, but device complexity increases
Solution Approach 1:
The support function is segmented into a separate, removable insert component rather than being integrated into the FSW tool or the workpiece itself. This segmentation allows the insert to be independently designed, positioned, and removed, simplifying the overall system while providing the necessary support functionality.
Solution Approach 2:
The insert is designed as a simple, potentially disposable component that provides temporary support only during the welding process. After welding is complete, the insert can be removed or left in place, eliminating the need for complex permanent support structures. This approach reduces device complexity while maintaining manufacturing precision during the critical welding operation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The insert supports the workpieces during welding, maintaining the original dimensions and improving the strength and ductility of the welds, ensuring robust friction stir welds with desired properties.
Implementation Method 1
Friction stir welding (FSW) is a solid state joining process that uses frictional heat generated by a rotating tool to soften and intermix the metal in both parts to form a bond or weld between two workpieces
Data Source
AI summary
A friction stir welded assembly includes a first workpiece having an interior portion with opposed interior walls, a second workpiece having an interior portion with opposed interior walls, and an insert positioned within the interior portion of the first workpiece and the interior portion of the second workpiece. The insert extends between and abuts at least one of the opposed interior walls of the first workpiece and the opposed interior walls of the second workpiece and a friction stir weld is between the first workpiece to the second workpiece. A joining end of the first workpiece and a joining end of the second workpiece form a butt joint or a lap joint between the first and second workpieces, and the friction stir weld is a butt weld or a lap weld, respectively, between the first and second workpieces.