Determination of a Permissible Size Flaw in the Doublet III Toroidal Field Coil

摘要

The thick plates of copper alloy 155 used for toroidal field coils (B-coils) in Doublet III contain material flaws that originated during the manufacturing of the plate stock. The methodology is reviewed in which detailed stress analysis, fracture mechanics, and fatigue testing are used to determine what size material flaws are permissible within the finger-joint region of the B-coil for a specified service life of 100,000 cycles under the maximum operating field of 40 kG. This paper presents the results of fatigue investigations of copper alloy 155 containing natural flaws and also with intentionally induced cracks. The nondestructive testing methods used to locate and to determine the dimensions of flaws are reviewed. Service requirements and stress analysis of the B-coil are presented. (ERA citation 05:009515)