Reference stress solutions of flat end to cylindrical shell connection and comparison with design stresses predicted by codes

摘要

The integrity of flat end to cylindrical shellconnections (flat endcaps) operating in the creep regime has beenquestioned since some failures have occurred in the recent past,mainly as Type IV cracking in the weldment. Failures in endcapsare potentially dangerous due to the fact that a crack will evolvefrom the inside and final failure will take place as 'break beforeleak', which in turn makes detection difficult. The codes treat thecomponent by calculating the cylinder and the flat endcapseparately, whereas failures occur in the transition between the twoin a cross-section not covered by the codes. This paper presentsreference stress solutions for endcaps derived from collapse loadsusing in Finite Element method. The computed reference stress canbe used for design and remaining life predictions. The referencestresses are compared to the predictions by some codes, and it isdemonstrated which combinations of geometries have the potentialfor premature failure. 2000 Elsevier Science Ltd. All rights reserved.