The control algorithm for passing through resonance zone for the two-rotor vibration unit is proposed and analyzed by computer simulation. The algorithm is based on speed-gradient method and leads to the significant reduction of the required level of the controlling torque. The algorithm is simple and has only two design parameters, though the system possesses complex and, apparently, chaotic b...

The vibration analysis of rotating machinery can give an indication of the condition of potential faults such as unbalance, bent shaft, shaft crack, bearing clearance, rotor rub, misalignment, looseness, oil whirl and whip and other malfunctions. The diagnostics of rotor faults has gained importance in recent years. Many papers in the literature have dealt with single faults but normally, more ...

The optimum design of a flexible rotor supported on three-lobe bearings, overhung centrifugal compressor, is studied for the optimal unbalance response using the genetic algorithm (GA) and method of feasible directions (MFD). The MFD is used to verify the GA results. The feasibility, effectivness, and avaliability of the GA is certainly of value because it allows the exploration of many differe...

The switching control algorithm for passing through resonance zone for the two-rotor vibration unit is proposed. The algorithm is based on speed-gradient method and leads to the significant reduction of the required level of the controlling torque. The dynamics of the overall hybrid system and its robustness against changes of spring stiffness, excentricity of rotors and damping is analyzed by ...

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Currently the lifespan of rotor blades is determined based on a conservative lifetime calculation. This leads to blades being discarded while they still possess a significant residual amount of flight-hours. Blade health monitoring systems are desired to actively track the strains in the blade thereby drastically extending the technical life expectancy. A major drawback is in the need for an el...

Abstract The most important faults of rotating machines can be modelled by means of proper sets of equivalent excitations having a suitable harmonic content. Therefore, mathematical models of rotating machines can be used by fault identification techniques that compare the experimental vibration data to the corresponding theoretical response of the rotor-system caused by a specific set of excit...

Bearings are widely used in various industries to support rotating shafts. Their failures accelerate failures of other adjacent components and may cause unexpected machine breakdowns. In recent years, nonlinear vibration responses collected from a dynamic rotor-bearing system have been widely analyzed for bearing diagnostics. Numerous methods have been proposed to identify different bearing fau...

Endoscopes for industrial and medical fields are expected to have multi degree-of-freedom (DOF) motions. A multi-DOF ultrasonic motor we developed consists of a spherical rotor and a bar-shaped stator, and the rotor rotates around three perpendicular axes using three natural vibration modes of the stator. In this study, a multi-DOF unilateral master-slave system for active endoscope using the m...

Three phase Squirrel Cage Induction Motors (SCIM) are continuously subjected to electrical, thermal, mechanical and environmental stresses in any industrial application. Such stresses can result in rotor bar damage. Due to such faults an unsymmetrical magnetic field will be setup and can lead to reduction in developed torque, increase in speed fluctuations, noise and vibrations. The present wor...