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Friction stir weld restart+reweld repair allowables
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Clifton, Andrew |
| Copyright Year | 2008 |
| Description | A friction stir weld (FSW) repair method has been developed and successfully implemented on Al 2195 plate material for the Space Shuttle External Fuel Tank (ET). The method includes restarting the friction stir weld in the termination hole of the original weld followed by two reweld passes. Room temperature and cryogenic temperature mechanical properties exceeded minimum FSW design strength and compared well with the development data. Simulated service test results also compared closely to historical data for initial FSW, confirming no change to the critical flaw size or inspection requirements for the repaired weld. Testing of VPPA fusion/FSW intersection weld specimens exhibited acceptable strength and exceeded the minimum design value. Porosity, when present at the intersection was on the root side toe of the fusion weld, the "worst case" being 0.7 inch long. While such porosity may be removed by sanding, this "worst case" porosity condition was tested "as is" and demonstrated that porosity did not negatively affect the strength of the intersection weld. Large, 15-inch "wide panels" FSW repair welds were tested to demonstrate strength and evaluate residual stresses using photo stress analysis. All results exceeded design minimums, and photo stress analysis showed no significant stress gradients due to the presence of the restart and multi-pass FSW repair weld. |
| File Size | 344059 |
| Page Count | 31 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_20080036249 |
| Archival Resource Key | ark:/13960/t86h9j66n |
| Language | English |
| Publisher Date | 2008-06-23 |
| Access Restriction | Open |
| Subject Keyword | Metals And Metallic Materials Welded Joints Stress Analysis External Tanks Stress Distribution Friction Stir Welding Space Shuttles Weld Strength Fusion Welding Inspection Porosity Design Analysis Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
