Exploration of NDE Properties of AMB Supported Rotors for Structural Damage Detection

Recent advancements in actuator technology, power electronics, sensors, and signal processing have created a rapid development of smart machine technologies for rotating machinery. Ranging from machine condition monitoring and diagnostics to full active control of machine behavior, the integration of electrical and computer systems has produced significant advances in machine performance and reliability. Magnetic bearings are a typical mechatronics product. The hardware is composed of mechanical components combined with electronic elements such as sensors and power amplifiers and an information processing part, usually in the form of a microprocessor. In addition, an increasingly important part is software, which specifies the coordination of bearing forces to sensed rotor motion and consequently dictates the dynamic properties of the complete system. The inherent ability for sensing, information processing, and actuation gives the magnetic bearing the potential to become a key element in smart and intelligent machines

Exploration of NDE Properties of AMB Supported Rotors for Structural Damage Detection

Recent advancements in actuator technology, power electronics, sensors, and signal processing have created a rapid development of smart machine technologies for rotating machinery. Ranging from machine condition monitoring and diagnostics to full active control of machine behavior, the integration of electrical and computer systems has produced significant advances in machine performance and reliability. Magnetic bearings are a typical mechatronics product. The hardware is composed of mechanical components combined with electronic elements such as sensors and power amplifiers and an information processing part, usually in the form of a microprocessor. In addition, an increasingly important part is software, which specifies the coordination of bearing forces to sensed rotor motion and consequently dictates the dynamic properties of the complete system. The inherent ability for sensing, information processing, and actuation gives the magnetic bearing the potential to become a key element in smart and intelligent machines

Smart Rotating Machines for Structural Health Monitoring

The objective of this thesis is to explore an innovative approach to the on-line health monitoring of rotating machinery in the presence of structural damage using active magnetic bearings (AMBs). First, the detailed model of the rotor with the breathing transverse crack is developed using finite element method. Next, the experimental data from the rotating magnetically levitated healthy and cracked shafts, under specially designed external excitation force, was collected, analyzed and compared with the computer simulation. The obtained results demonstrate that the presented on-line health monitoring technique is very effective for detection of the structural damage in rotating machinery, and it has a potential to be effectively applied in industr

Smart Rotating Machines for Structural Health Monitoring

The objective of this thesis is to explore an innovative approach to the on-line health monitoring of rotating machinery in the presence of structural damage using active magnetic bearings (AMBs). First, the detailed model of the rotor with the breathing transverse crack is developed using finite element method. Next, the experimental data from the rotating magnetically levitated healthy and cracked shafts, under specially designed external excitation force, was collected, analyzed and compared with the computer simulation. The obtained results demonstrate that the presented on-line health monitoring technique is very effective for detection of the structural damage in rotating machinery, and it has a potential to be effectively applied in industr

Smart Rotating Machines for Structural Health Monitoring

The objective of this thesis is to explore an innovative approach to the on-line health monitoring of rotating machinery in the presence of structural damage using active magnetic bearings (AMBs). First, the detailed model of the rotor with the breathing transverse crack is developed using finite element method. Next, the experimental data from the rotating magnetically levitated healthy and cracked shafts, under specially designed external excitation force, was collected, analyzed and compared with the computer simulation. The obtained results demonstrate that the presented on-line health monitoring technique is very effective for detection of the structural damage in rotating machinery, and it has a potential to be effectively applied in industr

On the future of controllable fluid film bearings

This work gives an overview of the theoretical and experimental achievements of mechatronics applied to fluid film bearings. Compressible and uncompressible fluids are addressed. Rigid and elastic (deformable) bearing profiles are investigated. Hydraulic, pneumatic, magnetic and piezoelectric actuators are used. The ideas of combining control techniques, informatics with hydrodynamic, thermo-hydrodynamic, elasto-hydrodynamic and thermo-elasto-hydrodynamic lubrication techniques are carefully explored in this paper, considering theoretical as well as experimental aspects. The main goal of using controllable fluid film bearings is to improve the overall machine performance by: controlling the lateral vibration of rigid and flexible rotating shafts; modifying bearing dynamic characteristics, such as stiffness and damping properties; increasing the rotational speed ranges by enhancing damping and eliminating instability problems, for example, by compensating cross-coupling destabilizing effects; reducing start-up torque and energy dissipation in bearings; compensating thermal effects. It is shown that such controllable fluid film bearings can act as “smart” machine components and be applied to rotating and reciprocating machines with the goal of avoiding unexpected stops of plants, performing rotor dynamic tests and identifying model parameters “on site”. Emphasis is given to the controllable lubrication (hybrid and active) applied to different types of oil film bearings under different lubrication regimes, i.e., as tilting-pad journal bearings, multi-recess journal bearings and plain journal bearings. After a comprehensive overview of the theoretical and experimental technological advancements achieved in university laboratories, the feasibility of industrial applications is highlighted, trying to foresee the future trends of such mechatronic devices

Vibration Modelling and Control Experiments for a Thin-Walled Cylindrical Rotor with Piezo Patch Actuation and Sensing

This paper describes a dynamic model formulation and control experiments concerning the vibration behaviour of a thin-walled cylindrical rotor with internal piezoelectric patch transducers. Model development, validation and controller design procedures were undertaken for an experimental rotordynamic system comprising a tubular steel rotor (length 0.8 m, diameter 0.166 m and wall-thickness 3.06 mm) supported by two radial active magnetic bearings. Analytical solutions for mode shapes and natural frequencies for free vibration were first derived using a shell theory model, and these used to construct a speed-dependent parametric model for the rotor structure, including piezo patch actuators and sensors. The results confirm that the developed shell theory model can accurately capture the rotating frame dynamics and accounts correctly for frequency splitting from Coriolis effects. The model is also shown to be suitable for active controller design and optimization. Model-based H2 feedback control using the rotor-mounted actuators and sensors is shown to achieve vibration suppression of targeted flexural modes, both with and without rotation

Dynamics Of Rotor Supported By Magnetic Bearing

This paper presents a study of the dynamic behavior of a rotor system supported by magnetic bearing. Specifically, the work investigate the range of realistic operating parameters that evolve around the rotation pattern of magnetically supported rotor, the vibration that occurs during the operation and the results difference after adjustments of some input parameters. The simulations of rotating rotor with magnetic bearing supports will be executed using ANSYS software. By varying the damping ratio and stiffness coefficient, the simulation shall produce different results. With the simulation, the research can identify the limit to instability by varying the damping of bearing during operation, thus, suggest recommendations on improvement of stability of magnetic supported rotor system

Health Monitoring of Cracked Rotor Systems Using External Excitation Techniques

Cracked rotors present a significant safety and loss hazard in nearly every application of modern turbomachinery. This thesis focuses on the health monitoring, modeling, and analysis of machines with transverse breathing cracks, which open and close due to the self-weight of the rotor. After considering the modeling of cracked rotors, the thesis investigates an active structural health monitoring approach, focusing on the application of an active magnetic actuator to apply a specially designed external force excitation to the rotating shaft. Extensive experimental data has been collected and analyzed utilizing advanced diagnostic techniques. The presented results demonstrate that the use of a magnetic force actuator to apply external excitation has potential in the diagnostics of cracked rotors. The observed unique crack signatures demonstrate the ability of the method for early diagnosis of transverse rotor crack

Health Monitoring of Cracked Rotor Systems Using External Excitation Techniques

Cracked rotors present a significant safety and loss hazard in nearly every application of modern turbomachinery. This thesis focuses on the health monitoring, modeling, and analysis of machines with transverse breathing cracks, which open and close due to the self-weight of the rotor. After considering the modeling of cracked rotors, the thesis investigates an active structural health monitoring approach, focusing on the application of an active magnetic actuator to apply a specially designed external force excitation to the rotating shaft. Extensive experimental data has been collected and analyzed utilizing advanced diagnostic techniques. The presented results demonstrate that the use of a magnetic force actuator to apply external excitation has potential in the diagnostics of cracked rotors. The observed unique crack signatures demonstrate the ability of the method for early diagnosis of transverse rotor crack