PHOTOSTRESS ANALYSIS OF THE LOWER WELD OF AN AFT SKIRT OF A SOLID ROCKET BOOSTER

摘要

Previous work using photostress on gas tungsten arc welded (GTAW) heat treated tensile specimens of 2219-T87 base metal and 2319 weld metal indicated that behavior of the joint can be highly irregular and non-uniform.1^ Welded joints 1.40 in. thick exhibited a totally non-uniform behavior through the weld thickness with the outside diameter (OD) side of the weld being much more ductile than the inside diameter (ID) side. Here, (OD) and {ID) refer to the outside and inside diameters of the aft skirt of the solid rocket booster (SRB) respectively. It has been shown3 that this difference in behavior through the weld is, in part, caused by procedures used when laying the weld bead. Joints similar to those tested and reported in Refs. 1 through 4 are an integral part of the aft skirt of the SRB of the shuttle. Since the ultimate safety factor for the lower portion of the weld is below the minimum required safety factor, a photostress analysis of this lower portion was conducted in the vicinity of the weld (see Fig. 1).