An aeroelastic analysis based on finite elements in space and time is used to model the helicopter rotor in forward flight. The rotor blade is represented as an elastic cantilever beam undergoing flap and lag bending, elastic torsion and axial deformations. The objective of the improved design is to reduce vibratory loads at the rotor hub that are the main source of helicopter vibration. Constr...

this work deals with effects of asymmetric stiffness on the dynamic behaviour of the rotor system. the analysis is presented through an extended lagrangian hamiltonian mechanics on the asymmetric rotor system, where symmetries are broken in terms of the rotor stiffness. the complete dynamics of asymmetries of rotor system is investigated with a case study. in this work, a mathematical model is ...

This paper introduces a procedure to model the dynamics of active slender structures with embedded actuators and sensors. The objective is to construct a loworder high-accuracy formulation for easy parameterization of the design space in nonlinear aeroelastic analysis. Main assumptions are small local strains and local rotations, large deflections and global rotations, quasielectrostatic behavi...

Modern utility-scale wind turbines are typically controlled using yaw, generator torque, and blade pitch actuation (Pao and Johnson, 2011). The yaw motor is used to align the rotor with the wind direction for the purpose of maximizing power capture. Generator torque is controlled during below-rated (region 2) operation to maximize power capture by maintaining the optimal tip speed ratio. In abo...

most of the methods that have been proposed for speed estimation of induction machines require the rotor and the stator resistance to change in the normal operating range. on the other hand, estimation of the rotor resistance requires rotor speed. in this paper, after studying conditions for simultaneous estimation of rotor speed and rotor resistance, a method for simultaneous estimation of rot...

the rotor of enegelberg whitener was equipped with a screw conveyor to reduce broken rice percentage. according to preliminary experiments this modification could reduce broken rice percentage about 2.5%. further experiment was performed to determine the effect of rotor speeds and blade positions on white rice quality. to do this, five rotor speeds, consisting 500, 600, 700, 800 and 900 r.p.m a...

In forward flight, slowing down a rotor alleviates compressibility effects on the advancing side blade tip, extending cruise speed limit, and inducing high-advance-ratio flight regime. Previous wind tunnel tests have shown that an articulated trimmed to zero hub moment generates limited thrust at high advance ratios, because needs be against retreating with significant reverse flow, where is in...

The nonlinear dynamic effects of the misalignment between inner disks in a flawed–machining rod–disk rotor is studied. Non–uniform stress distribution due to obtained based on 3D static solution. concomitant unbalances, including constant mass eccentricity and speed–variant bending, are taken into account dynamics. results show that bending leads stability reduction vibration growth. There dist...