Challenge

A subsea pipeline was plastically deformed due to accidents. Mechanical tests needed to be performed in order to assess the pipeline integrity after the introduction of this deformation. An urgent engineering critical assessment (ECA) needed to be made.

Approach

The approach of the MSC partners consisted in:

  • Pre-deformation, ageing & evaluation of base material properties
  • Determination of J-R curve for HAZ & weld metal (SENB / SENT)
  • Cyclic & monotonic coupon tests with artificially produced defects
  • FEM to evaluate required load for crack extension
  • Pre-straining and weld tensile tests
  • SSCC tests in deformed conditions

Benefit

The outcome was the validation of the ECA with maximum defect size. As a result the integrity of the pipeline could be confirmed, avoiding the replacement cost of the line.
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