A. Toskey, W. Arbegast, A. Patnaik, C. Allen, South Dakota School of Mines and Technology, Rapid City, SD

Summary:

Friction stir welding is being investigated as a method of joining two extruded aluminum C-channels along the length to create a hollow box beam. This can provide a cost effective alternative to extruding hollow box beams as a single piece. The research work comprised the development of design and analysis methodologies for friction stir welded box beams, and structural testing to evaluate the behavior of friction stir welded beams. The tests include coupon tests, sub-element tests on short beams, and long beam bending tests. The beam tests will comprise four point bending tests on beams with a span of 6 to 8 ft. Results of coupon tests to determine mechanical properties and the metallurgical characteristics of the welds, mechanical properties of base metal in the heat affected zones will also be presented. The results of static bending tests of 6 to 8 ft. long beams joined in either the flanges or in the webs will be presented. Strain distributions around welds in high stress zones determined by digital image correlation techniques will also be presented. A comparison will be made between the results of bending test of hollow extrusions and the test results of beams joined by friction stir welding for the corresponding cross-sectional dimensions and spans. Test results will also be compared to the predictions from analytical and numerical models.