In this study, a novel and very simple finite element procedure is presented for free vibration and buckling analysis of slim beam-like structures damaged by edge cracks. A cracked region of a beam is modeled using a very short element with reduced second moment of area (I). For computing reduced I in a cracked region, the elementary theory of bending of beams and local flexibility approach are...

Gaussian processes prior model methods for data analysis are applied to wind turbine time series data to identify both rotor speed and rotor acceleration from a poor measurement of rotor speed. In so doing, two issues are addressed. Firstly, the rotor speed is extracted from a combined rotor speed and generator speed measurement. A novel adaptation of Gaussian process regression based on two in...

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: An innovative design of a magnetic coupler for shaft speed amplification is proposed and verified by experiments. The structure of the proposed magnetic coupler is similar to an infinite-stage gearbox. In addition, the mathematical model of flux density is derived to look into the equation of adjustable gear ratio and effect of speed amplification. Moreover, two sets of experiments, n...

air spindles are one of the main elements of precise machine tools. vibration of these spindles is one of the vital issues necessary for investigation. among parameters which influence air spindle vibrations are rotational speed, compression air method, input nozzle diameter, air gap pressure. in this study using ansys, the effects of air gap thickness on air spindle vibrations have been invest...

The Magneto-Electro-Elastic (MEE) material exhibits pyroelectric and pyromagnetic effects under thermal environment. The effects of such pyroelectric and pyromagnetic behavior on vibration, buckling and deflection analysis of partially cracked thin MEE plate is presented and discussed in this paper. The aim of the study is to develop an analytical model for the vibration and geometrically linea...

For line start permanent magnet synchronous machines (LSPMSMs), the eddy current loss in the rotor, which has of significant effects on rotor working temperature, may cause thermal demagnetization to permanent magnet. Therefore, this paper addresses an investigation on the temperature distribution in LSPMSM based on a 6 kV, 315 kW prototype with solid starting cage bar. Firstly, the loss distri...

A new squirrel-cage rotor structure induction motor (IM) that has a auxiliary permanent magnet (PM) rotor and improved cage-rotor structure is presented to enhance the inherent power factor of the IM, and a prototype motor is fabricated by modifying the rotor of a conventional three-phase four-pole squirrel-cage induction motor. The flux linkage, flux distribution, power factor, core loss and e...

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...

A probabilistic methodology has been developed for fracture-mechanics analysis of nonlinear cracked structures. The methodology involves nonlinear ®nite element analysis using well-known commercial codes; statistical models for uncertainty in material constitutive law, fracture toughness, and loads; and standard reliability methods for evaluating probabilistic characteristics of elastic±plastic...