Seismic

Overview

The analysis of wind turbine loading associated with earthquakes is clearly important when designing for, and assessing the feasibility of wind farms in seismically active regions. The approach taken for such analysis is generally based on codified methods which have been developed for the assessment of seismic loads acting on buildings. These methods are not able to deal properly with the aeroelastic interaction of the dynamic motion of the wind turbine structure with either the wind loading acting on the rotor blades or the response of the turbine controller.

The Seismic module within Bladed allows the full aeroelastic model of the wind turbine subject to turbulent wind loading to be further excited by ground motion corresponding to the earthquake.

Earthquake modelling

• Synthetic or measured earthquake events can be used.
• Compatible with all major building codes including the Eurocode8, the Uniform Building Code (UBC), the International Building Code (IBC) and many local standards.
• Synthetic earthquakes are generated from a target or design response spectrum.
• Earthquakes can be generated with characteristics that represent stiff or soft soils.
• A secondary component of acceleration can be applied at 90 degrees to the main component This can be either proportional to the main component or statistically independent.

Load calculation

• Time-domain simulations ensure accurate representation of non-linear effects, such as the interaction of the turbine control and safety system and the rotor aerodynamics.
• The earthquake can be applied in any direction, and this is independent of the direction of the wind or waves.
• Calculations can be carried out as part of a site specific study and processed using the normal post-processing tools provided within Bladed.

Validation

• Fully validated against frequency domain methods.
• Was tested and approved by Germanischer Lloyd.