A subsea pipeline was plastically deformed due to accidents. The outcome was the validation of the engineering ciritcal assessment (ECA) with maximum defect size.
A pipeline constructor asked to check and validate the design of PU spacers protecting a 3LPE (3-layer polyethylene) coating during the pulling of a pipeline section through a concrete tunnel.
The question was raised under which condition of weather and leg height, resonance of a jack-up barge could occur. A safe operational window to avoid lock-in of the legs was identified and critical conditions have been determined.
The stability of subsea pipelines, marine risers and offshore structures can be compromised by fluid-structure interaction. Vortex induced vibrations lead to fatigue of flow lines under free span and risers. It was possible to determine the loading pattern and compare it to the pipeline’s characteristics.
Fatigue analysis of a mid-size wind turbine hub at various load conditions was requested. Furthermore, a comparison between welded and cast hubs was needed. The computation demonstrated that it was possible to use a welded hub
For offshore pipe laying purposes, an investigation was made on the friction behaviour of several composite materials. The best composite material was selected in terms of its static and dynamic friction and shear behaviour.
Cost reduction is an important topic in the offshore wind sector. However, in view of the move to larger turbine sizes and deeper waters, costs of foundation structures will rise. It is now possible to test tubular joints having the dimensions of offshore wind turbine jacket structures at millions of cycles within a week and with low energy consumption.
As threaded connections are submitted to variable loading they can suffer from fatigue. The critical locations for fatigue were determined and confirmed by experiments. The large scale resonant bending test proved to be valuable test equipment.
A manufacturer asked to perform cathodic disbondment tests on blasted steel panels coated with a multi-layer polymer system. Delamination distance was determined and a relative coating performance rating was obtained, clearly identifying the best solution for the application.
The owner of an onshore X52 pipeline (diameter 12 inch) wanted to assess the safety risk of the pipeline over time. In all test samples, failure occurred at a number of cycles larger than the expected number of cycles in service. For the considered metal loss reduction and crack depth, the pipes can be considered as safe over its fifty year service life.
The customer asked MSC to investigate the possibility of replacing currently used cast steel brackets welded to spud pillars by high strength steel brackets. The survey revealed that the use of high strength steel instead of the current cast steel would be an interesting option for new projects.
Reeled pipelines are submitted to cyclic deformation during reeling and unreeling operations. The behaviour of the plastic deformed pipe needed assessment. The ultra-low cycle fatigue characteristics of the pipe were determined as well as the feasibility of the pipe to multiple bending cycles.
A pipe coater experienced cracking issues in the top layer of dual layer fusion bonded epoxy systems (FBE) during large scale bending tests at low temperature. White spots show to be the preferred crack initiation location. The customer was advised to select a better adhering fusion bonded epoxy (FBE) and to optimise cleaning efficiency. Since, the pipe coater no longer experiences cracking issues.