in the present paper, the aeroelastic stability of helicopter rotor blade is determined using aeroelastic frequency response function. the aeroelastic model of blade is obtained by combining dowell - hodges beam model with loewy unsteady aerodynamic theory which considers an unsteady wake beneath the rotor. equations are formed and aeroelastic frequency response functions are obtained by invert...

This work deals with the application of an active unbalance compensation scheme for a rotor-bearing system by simultaneously using two control strategies, consisting in the synthesis of a dynamic stiffness controller and the acceleration scheduling for the rotor speed. The rotor-bearing system consists of an asymmetrical Jeffcott-like rotor system with a servomechanism to position a sliding bea...

Abstract—In this study the regional stability of a rotor system which is supported on rolling bearings with radial clearance is studied. The rotor is assumed to be rigid. Due to radial clearance of bearings and dynamic configuration of system, each rolling elements of bearings has the possibility to be in contact with both of the races (under compression) or lose its contact. As a result, this ...

Harmonic vibrations of high-speed rotors in momentum exchange devices are primary disturbances for attitude control of spacecraft. Active magnetic bearings (AMBs), offering the ability to control the AMB-rotor dynamic behaviors, are preferred in high-precision and micro-vibration applications, such as high-solution Earth observation satellites. However, undesirable harmonic displacements, curre...

The paper presents a novel secondary reactance control technique in the rotor circuit of a three phase wound rotor induction motor (WRIM). The problem associated with the conventional rotor capacitive reactance control is the demand of exceptionally large capacitance requirement for enhancing the performance of the motor in wide operating range. In the proposed technique, a three phase bridge r...

Problem statement: The Rotor reactance control by inclusion of external capacitance in the rotor circuit has been in recent research for improving the performances of Wound Rotor Induction Motor (WRIM). The rotor capacitive reactance is adjusted such that for any desired load torque the efficiency of the WRIM is maximized. The rotor external capacitance can be controlled using a dynamic capacit...

The paper proposes a methodology for reliable design and maintenance of wind turbine rotor blades using a condition monitoring approach and a damage tolerance index coupling the material and structure. By improving the understanding of material properties that control damage propagation it will be possible to combine damage tolerant structural design, monitoring systems, inspection techniques a...

This report contains the results of a full-scale experimental feasibility study of rotor isolation employing the Dynamic Antiresonant Vibration Isolator (DAVI) . The full-scale experiments were performed on a UH-2 helicopter fuselage isolated from a simulated rotor and transmission. Tests were conducted for three directions of vibratory input at the hub on the nonisolated vehicle and then compa...

The purpose of this study was to explore the complex flow structure a novel active-type micromixer that based on concept of Wankle-type rotor. The characteristics of this micromixer are two folds; a rapid mixing of reagents in a limited space due to the generation of multiple vortices and a graduate increment in dynamic pressure as the mixed reagents is delivered to the output ports. Present mi...

Title of Dissertation: A Coupled CFD/CSD Investigation of the Effects of Leading Edge Slat on Rotor Performance Asitav Mishra, Doctor of Philosophy, 2012 Dissertation directed by: Associate Professor James D. Baeder Department of Aerospace Engineering A coupled Computational Fluid Dynamic (CFD) and Computational Structural Dynamics (CSD) methodology is extended to analyze the effectiveness of a...