New Residual Stress Mapping Tool Applied to Atlas Current Joint Design

A redesigned cylindrical liner system has been implemented for use on the Atlas capacitor bank. This new design dramatically changes how the liner, glide planes and current joints of the system are formed. The previous design relied on interference of the liner with the glide plane by thermal shrink fit using liquid nitrogen coolant to form current joints. The new design achieves the required fit by mechanically distorting soft metals with a swaged joint. In this paper, we present the results of the first application of a new residual stress mapping technique, the contour method, to the design and fabrication process of the Atlas upper current joint. One of the strengths of the contour method is that it provides a full cross-sectional map of the residual-stress component normal to the cross section. The results showed significant stresses in the stainless steel glide plane with expected maximum compression near the joint and stresses in the aluminum part liner and return current conductor that corresponds well with measured form distortions.