Mitigation of flow-induced pulsations in flexibles at field conditions with liquid injection

Flexible corrugated pipes as used for the transport of gas in offshore deepwater applications can generate undesired flow-induced pulsations (FLIP). This phenomenon has been also traditionally called “singing risers”. The pulsations generated may result in high-amplitude cyclic stresses in the pipe systems attached to the flexible. Moreover, an...

Approach to include load sequence effects in the design of an offshore wind turbine substructure

Fatigue is one of the main design drivers for offshore wind substructures. Using Fracture Mechanics methods, load sequence effects such as crack growth retardation due to large load peaks can be included in the fatigue damage estimation. Due to the sequence dependency, a method is required that represents the sequences of loads in the design or...

Including load sequence effects in the fatigue damage estimation of an offshore wind turbine substructure

Retardation is a load sequence effect, which causes a reduced fatigue crack growth rate after an overload is encountered. Retardation can be cancelled when the overload is followed by an underload. The net effect is beneficial to the fatigue lifetime of Offshore Wind Turbines (OWTs). To be able to take this into account, computationally...

Development and validation of a low-cost CTOD procedure

A low-cost variation of CTOD testing is proposed. This variation follows BS7448, but has several nonstandard deviations, including: • Using a fixed notch width of 0.5 mm. • Using fatigue pre-cracks that are shorter than normal requirements to save the associated expense. • Using Single Edge Notched 3-point Bending (SENB) specimens with cross...