Development and Validation of a Modal Analysis Code for Wind Turbine Blades

QBlade is an open source wind turbine design and simulation tool developed at the Berlin Institute of Technology. To enable a coupling with the aeroelastic simulation tool FAST from NREL an aditional module, called QFEM, was created and integrated with QBlade. This module performs a modal analysis on rotor blades designed in QBlade using isotropic tapered Euler Beam elements. The newly developed module now provides structural properties to the National Renewable Energy Laboratorys aeroelasticity simulation tool FAST. The 2D structural properties of the beam elements are created using integration methods. A number of test cases show that the 2D integration methods and beam element code work with adaquete accuracy. The integration of the modal analysis code greatly facilitates the structural design and analysis of rotor blades and will be made available to the public under an open source license.