PRCI PR-140-120

L51413e

Welding Institute of Canada

Need: The use of fitness-for-purpose analyses is being increasingly used in the assessment of the safety of gas pipelines. The need for this arises because of potential defects in the girth weld, which is in the as-welded condition. These analyses require data on the defect size and nature, the toughness of the material the defect lies in and the applied stress levels. One of the problem data areas is knowing the applied stress level especially when residual stresses have to be considered. The effect of these secondary stresses on fracture behavior is extremely important; in addition, knowledge of how to incorporate them into a fracture model is desired.

Result: This project has studied the generation of residual stresses in a stress free bar by a variety of means including mechanical loading and thermal means. The stress distributions generated have been compared to theoretical analyses and found to compare very well. The use of a mechanical loading system can produce a complex stress system up to a maximum of half the yield stress. Non-uniform cooling produces a simpler stress distribution with a maximum tensile stress in the center of the bar up to the yield stress.


Benefit: This research program has studied the effect of residual stress on fracture behavior for plain materials. The work covered the modeling of stress distributions under varying conditions and the evaluation of toughness in the presence of residual stress.

Product Details

Published:

10/01/1981

Number of Pages:

96

File Size:

1 file , 1.7 MB