The bifurcation analysis of a composite beam subjected to harmonic flapwise base excitation is studied when the ratio of flapwise and chordwise internal resonances is 1:2. Results are obtained by the numerical solution of modulation equations. Chracteristics of the response are investigated in terms of time history, phase portraits diagrams and bifurcation diagram of poincare maps. It is observ...

Abstract: Wind turbine blades have to withstand the rigorous test of 20–25 years of service. Fatigue testing is an accurate method used to verify blade reliability. Multi-point excitation could better fit the fatigue damage distribution, which reduces the power output of a single exciter and saves testing energy consumption. The amplitude, phase, and frequency characteristics of the fatigue tes...

Aiming at the drift problem that tracking control of actual load relative to target during electromagnetic excitation biaxial fatigue test wind turbine blades is easy drift, a testing machine for designed, and following strategy studied. A Fast Transversal Recursive Least Squares algorithm based on fuzzy logic (Fuzzy FTRLS) proposed develop loading dynamic strategy, which adjusts forgetting fac...

The load-induced deformations experienced by axial-flow rotor blades can result in significant hydrodynamic impacts on operation. These changes hydrodynamics are dominated the flapwise and twist deformation components, affecting blade loading performance. This work uses blade-resolved computational fluid dynamics simulations to explore interactions of coupled deformations, their potential for u...

A new turbine model validation technique that is based on adaptation of look-up tables is described this paper. Simulation results from the VIDYN turbine simulation program and measurements from Big Glenn wind turbine, located outside Gothenburg, Sweden are used as an input to this new model validation technique. The models of the flapwise bending moment and power coefficient are validated for ...

An approximate numerical mthod is presented for analysis and determination of modal characteristics in straight, pretwisted non-unifom helicopter blades. The analysis considers the coupled flapwise bending (out of plane), chordwise bending (in plane), and torsion vibration of both rotating and non-rotating blades. The proposed method is based on the integral expansion of Green functions (struct...

An approximate numerical mthod is presented for analysis and determination of modal characteristics in straight, pretwisted non-unifom helicopter blades. The analysis considers the coupled flapwise bending (out of plane), chordwise bending (in plane), and torsion vibration of both rotating and non-rotating blades. The proposed method is based on the integral expansion of Green functions (struct...

The increased size and flexibility of modern multi-Megawatt wind turbines has resulted in the dynamic behaviour of these structures becoming an important design consideration. The aim of this paper is to study the variation in natural frequency of wind turbine blades due to centrifugal stiffening and the potential use of semi-active tuned mass dampers (STMDs) in reducing vibrations in the flapw...