LONG RANGE REACTION STRESSES IN SHIP STRUCTURES

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Authors
  1. Malik, L.
  2. Cowper, B.
  3. Tyson, W.R.
Corporate Authors
Metals Technology Labs, Ottawa ONT (CAN);Defence Research Establishment Atlantic, Dartmouth NS (CAN)
Abstract
It is now recognized that in complex welded structures such as ships, long range reaction stresses develop due to assembly, fit-up, and structural restraint against the weld zone shrinkage. The long range reaction stresses are different from the short range weld residual stresses, the latter being always present in the weld zone, even if the weld is deposited on a small plate, free to move and contract. Such stresses can be ignored in fatigue design as yield level residual stresses are usually assumed to be present. However, in fracture assessment (for initiation or crack arrest), this could lead to unsafe predictions. Literature was, therefore, reviewed to assess the magnitude of such long range reaction stresses in ships. Early studies suggested it to be 25 to 30% of the steel's yield strength. However, due to the increasing use of higher strength steels, and the absence of any recent studies on this subject, a small investigation was undertaken to measure long range reaction stresses during the fabrication of a Super Ferry. The presentation will describe the results obtained which indicated that long range reaction stresses could exceed 75% of the yield strength.
Report Number
DREA-NAMT-93-3-PAP-10 — CONTAINED IN 99-00578
Date of publication
30 Apr 1993
Number of Pages
30
DSTKIM No
99-00588
CANDIS No
510315
Format(s):
Hardcopy;Document Image stored on Optical Disk

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