scholarly journals Effects of Eccentricity on the Dynamic Behavior for Electromechanical Integrated Toroidal Drive

2013 ◽  
Vol 20 (2) ◽  
pp. 273-286 ◽  
Author(s):  
Lizhong Xu ◽  
Haifeng Li
Keyword(s):  
Dynamic Behavior ◽  
Natural Frequencies ◽  
Drive System ◽  
The Other ◽  
Dynamic Equations ◽  
Electromechanical Integrated ◽  
Drive Systems ◽  
Forced Responses ◽  
Design And Manufacture ◽  
Center Distance

In electromechanical integrated toroidal drive, eccentric center errors occur which has important influences on the dynamic behavior of the drive system. Here, the dynamic equations of the drive system with eccentric center are presented. Changes of the natural frequencies and vibrating modes along with eccentric center distance are analyzed. The forced responses of the drive system to eccentric center excitation are investigated. Results show that the eccentric center causes some natural frequencies to increase, and the other natural frequencies to drop. It also causes some vibrations to become weak, and the other vibrations to become strong. The eccentric center has more obvious effects on the dynamic behavior of the planets. The results are useful in design and manufacture of the drive systems.

scholarly journals Nonlinear Forced Response of Electromechanical Integrated Toroidal Drive to Coupled Excitation

2012 ◽  
Vol 2012 ◽  
pp. 1-10
Author(s):  
Lizhong Xu ◽  
Fen Wang
Keyword(s):  
Natural Frequencies ◽  
Forced Response ◽  
Drive System ◽  
Mesh Stiffness ◽  
Electric Excitation ◽  
Time Period ◽  
Electromechanical Integrated ◽  
Exciting Frequency ◽  
Mesh Parameter ◽  
Forced Responses

The electric excitation and the parameter excitation from mesh stiffness fluctuation are analyzed. The forced response equations of the drive system to the coupled excitations are presented. For the exciting frequencies far from and near natural frequencies, the forced responses of the drive system to the coupled excitations are investigated. Results show that the nonlinear forced responses of the drive system to the coupled excitations change periodically and unsteadily; the time period of the nonlinear forced responses depends on the frequencies of the electric excitation, the mesh parameter excitation, and the nonlinear natural frequencies of the drive system; in order to improve the dynamics performance of the drive system, the frequencies of the electric excitations should not be taken as integral multiple of the mesh parameter exciting frequency.

Dynamic Displacements for Electromechanical Integrated Electrostatic Harmonic Drive

2008 ◽  
Vol 3 (3) ◽  
Author(s):  
Lizhong Xu ◽  
Lei Qin
Keyword(s):  
Natural Frequencies ◽  
Dynamic Performance ◽  
Three Dimensional ◽  
Frequency Equation ◽  
Drive System ◽  
Harmonic Drive ◽  
Electromechanical Integrated ◽  
Analysis Package ◽  
Design And Manufacture ◽  
Flexible Ring

The electromechanical integrated electrostatic harmonic drive is a new drive system invented by authors. The dynamic displacements of the flexible ring for the drive have important influence on operating performance of the drive system. In this paper, the three dimensional dynamic equations for the drive system are presented. The mode function equations and the frequency equation for the drive system are derived. The natural frequencies and dynamic displacements of the drive system are obtained. Using a finite element method analysis package, ANSYS, the natural frequencies and vibrating modes of the flexible ring for the drive system are simulated. The simulation results are compared to the analytical results above. The research is useful in design and manufacture of the drive system and can be used to design dynamic performance of the drive.

scholarly journals Natural Frequencies and Vibrating Modes for a Magnetic Planetary Gear Drive

2012 ◽  
Vol 19 (6) ◽  
pp. 1385-1401 ◽  
Author(s):  
Lizhong Xu ◽  
Xuejun Zhu
Keyword(s):  
Natural Frequencies ◽  
Planetary Gear ◽  
Drive System ◽  
Dynamic Equations ◽  
The Sun ◽  
System Parameters ◽  
Meshing Stiffness ◽  
Torsion Mode ◽  
Gear Drive ◽  
Pair Number

In this paper, a dynamic model for a magnetic planetary gear drive is proposed. Based on the model, the dynamic equations for the magnetic planetary gear drive are given. From the magnetic meshing forces and torques between the elements for the drive system, the tangent and radial magnetic meshing stiffness is obtained. Using these equations, the natural frequencies and the modes of the magnetic planetary gear drive are investigated. The sensitivity of the natural frequencies to the system parameters is discussed. Results show that the pole pair number and the air gap have obvious effects on the natural frequencies. For the planetary gear number larger than two, the vibrations of the drive system include the torsion mode of the center elements, the translation mode of the center elements, and the planet modes. For the planetary gear number equal to two, the planet mode does not occur, the crown mode and the sun gear mode occur.

scholarly journals Design and Production of Innovative Turbomachinery Components via Topology Optimization and Additive Manufacturing

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Enrico Meli ◽  
Andrea Rindi ◽  
Alessandro Ridolfi ◽  
Rocco Furferi ◽  
Francesco Buonamici ◽  
...  
Keyword(s):  
Topology Optimization ◽  
Additive Manufacturing ◽  
Dynamic Behavior ◽  
Oil And Gas ◽  
Natural Frequencies ◽  
Service Operations ◽  
Centrifugal Compressors ◽  
Manufacturing Resources ◽  
Mechanical Performances ◽  
Design And Manufacture

The present paper proposes a methodology to design and manufacture optimized turbomachinery components by leveraging the potential of Topology Optimization (TO) and Additive Manufacturing (AM). The method envisages the use of TO to define the best configuration of the rotoric components in terms of both static and dynamic behavior with a resultant reduction of overall weight. Eventually, the topology-optimized component is manufactured by using appropriate materials that can guarantee valid mechanical performances. The proposed strategy has been applied to a 2D impeller used for centrifugal compressors to prove the effectiveness of a TO+AM-based approach. Although this approach has never been extensively used before to centrifugal compressors and expanders, its application on rotor and stator components might unlock several benefits: tuning the natural frequencies, a reduction in the stress level, and a lighter weight of the rotating part. These objectives can be reached alone or in combination, performing a single analysis or a multiple analyses optimization. Finally, the introduction of AM technologies as standard manufacturing resources could bring sensible benefits with respect to the time to production and availability of components. Such aspects are essential in the Oil and Gas context, when dealing with new projects but also for service operations.

Coupling Effects in a Manipulator With Both a Flexible Link and Joint

1994 ◽  
Vol 116 (4) ◽  
pp. 826-831 ◽  
Author(s):  
F. Xi ◽  
R. G. Fenton ◽  
B. Tabarrok
Keyword(s):  
Natural Frequencies ◽  
Coupling Effect ◽  
Joint Stiffness ◽  
The Other ◽  
Dynamic Equations ◽  
Mode Shapes ◽  
Flexible Link ◽  
Flexible Joint ◽  
Special Cases ◽  
The Moment

The manipulator considered in this paper consists of a flexible link and a flexible joint. The coupling effect between link and joint deflections is investigated. The dynamic equations for the of manipulator are derived and analytical solutions are obtained. It is shown that the natural frequencies and mode shapes of a manipulator with both a flexible link and joint may be parametrized in terms of two ratios. One is the ratio of the moment of inertia of the link to that of the rotor and the other is the ratio of the link stiffness to the joint stiffness. Two special cases are discussed: (1) a manipulator with a relatively flexible link and a relatively rigid joint; and (2) a manipulator with a relatively flexible joint and a relatively rigid link.

scholarly journals Vibration of Rotating and Revolving Planet Rings with Discrete and Partially Distributed Stiffnesses

2020 ◽  
Vol 11 (1) ◽  
pp. 127
Author(s):  
Fuchun Yang ◽  
Dianrui Wang
Keyword(s):  
High Speed ◽  
Differential Operators ◽  
Natural Frequencies ◽  
Rotation Speed ◽  
Distribution Area ◽  
Vibration Modes ◽  
Governing Equations ◽  
Vibration Properties ◽  
Wide Range ◽  
Forced Responses

Vibration properties of high-speed rotating and revolving planet rings with discrete and partially distributed stiffnesses were studied. The governing equations were obtained by Hamilton’s principle based on a rotating frame on the ring. The governing equations were cast in matrix differential operators and discretized, using Galerkin’s method. The eigenvalue problem was dealt with state space matrix, and the natural frequencies and vibration modes were computed in a wide range of rotation speed. The properties of natural frequencies and vibration modes with rotation speed were studied for free planet rings and planet rings with discrete and partially distributed stiffnesses. The influences of several parameters on the vibration properties of planet rings were also investigated. Finally, the forced responses of planet rings resulted from the excitation of rotating and revolving movement were studied. The results show that the revolving movement not only affects the free vibration of planet rings but results in excitation to the rings. Partially distributed stiffness changes the vibration modes heavily compared to the free planet ring. Each vibration mode comprises several nodal diameter components instead of a single component for a free planet ring. The distribution area and the number of partially distributed stiffnesses mainly affect the high-order frequencies. The forced responses caused by revolving movement are nonlinear and vary with a quasi-period of rotating speed, and the responses in the regions supported by partially distributed stiffnesses are suppressed.

scholarly journals Analysis of Torque Ripples of an Induction Motor Taking into Account a Inter-Turn Short-Circuit in a Stator Winding

Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3626 ◽  
Author(s):  
Wojciech Pietrowski ◽  
Konrad Górny
Keyword(s):  
Early Stage ◽  
Short Circuit ◽  
Torque Ripple ◽  
Drive System ◽  
Electrical Machines ◽  
Stator Winding ◽  
Permanent Magnet Synchronous Machines ◽  
Noninvasive Diagnostics ◽  
Drive Systems ◽  
Commercial Applications

Despite the increasing popularity of permanent magnet synchronous machines, induction motors (IM) are still the most frequently used electrical machines in commercial applications. Ensuring a failure-free operation of IM motivates research aimed at the development of effective methods of monitoring and diagnostic of electrical machines. The presented paper deals with diagnostics of an IM with failure of an inter-turn short-circuit in a stator winding. As this type of failure commonly does not lead immediately to exclusion of a drive system, an early stage diagnosis of inter-turn short-circuit enables preventive maintenance and reduce the costs of a whole drive system failure. In the proposed approach, the early diagnostics of IM with the inter-turn short-circuit is based on the analysis of an electromagnetic torque waveform. The research is based on an elaborated numerical field–circuit model of IM. In the presented model, the inter-turn short-circuit in the selected winding has been accounted for. As the short-circuit between the turns can occur in different locations in coils of winding, computations were carried out for various quantity of shorted turns in the winding. The performed analysis of impact of inter-turn short-circuit on torque waveforms allowed to find the correlation between the quantity of shorted turns and torque ripple level. This correlation can be used as input into the first layer of an artificial neural network in early and noninvasive diagnostics of drive systems.

scholarly journals Mechanical-Level Hardware-In-The-Loop and Simulation in Validation Testing of Prototype Tower Crane Drives

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5727
Author(s):  
Michał Michna ◽  
Filip Kutt ◽  
Łukasz Sienkiewicz ◽  
Roland Ryndzionek ◽  
Grzegorz Kostro ◽  
...  
Keyword(s):  
Laboratory Testing ◽  
Environmental Parameters ◽  
Experimental Tests ◽  
Drive System ◽  
Hardware In The Loop ◽  
Dynamic Simulations ◽  
Tower Crane ◽  
University Of Technology ◽  
New Type ◽  
Drive Systems

In this paper, the static and dynamic simulations, and mechanical-level Hardware-In-the-Loop (MHIL) laboratory testing methodology of prototype drive systems with energy-saving permanent-magnet electric motors, intended for use in modern construction cranes is proposed and described. This research was aimed at designing and constructing a new type of tower crane by Krupiński Cranes Company. The described research stage was necessary for validation of the selection of the drive system elements and confirmation of its compliance with applicable standards. The mechanical construction of the crane was not completed and unavailable at the time of testing. A verification of drive system parameters had to be performed in MHIL laboratory testing, in which it would be possible to simulate torque acting on the motor shaft. It was shown that the HIL simulation for a crane may be accurate and an effective approach in the development phase. The experimental tests of selected operating cycles of prototype crane drives were carried out. Experimental research was performed in the LINTE^2 laboratory of the Gdańsk University of Technology (Poland), where the MHIL simulator was developed. The most important component of the system was the dynamometer and its control system. Specialized software to control the dynamometer and to emulate the load subjected to the crane was developed. A series of tests related to electric motor environmental parameters was carried out.

Comparative Analysis of the Control Rod Drive System

2012 ◽  
Vol 614-615 ◽  
pp. 1558-1561
Author(s):  
Wen Wei Han ◽  
Wei Shi Han ◽  
Qing Guo
Keyword(s):  
Comparative Analysis ◽  
Drive System ◽  
Hydraulic Control ◽  
Control Rod ◽  
Rod System ◽  
Drive Systems ◽  
Research Situation

This article has systematically summarized the recent research situation of control rod system in China and comparatively analyzed the features of a variety of control rod drive systems on a basis of brief introduction of common types of control rod drive system. It has been proposed to that the hydraulic control rod drive system have a great potential in a wide application concerning on ships, warships power reactors and protable desalination system.

Studies on Determination of Natural Frequencies of Industrial Turbine Blades

1995 ◽  
Author(s):  
Mahesh M. Bhat ◽  
V. Ramamurti ◽  
C. Sujatha
Keyword(s):  
Steam Turbine ◽  
Dynamic Behavior ◽  
Turbine Blade ◽  
Natural Frequencies ◽  
Complex Structure ◽  
Turbine Blades ◽  
Blade Root ◽  
Steam Turbine Blade ◽  
Manufacturing Tolerances

Abstract Steam turbine blade is a very complex structure. It has geometric complexities like variation of twist, taper, width and thickness along its length. Most of the time these variations are not uniform. Apart from these geometric complexities, the blades are coupled by means of lacing wire, lacing rod or shroud. Blades are attached to a flexible disc which contributes to the dynamic behavior of the blade. Root fixity also plays an important role in this behavior. There is a considerable variation in the frequencies of blades of newly assembled turbine and frequencies after some hours of running. Again because of manufacturing tolerances there can be some variation in the blade to blade frequencies. Determination of natural frequencies of the blade is therefore a very critical job. Problems associated with typical industrial turbine bladed discs of a 235 MW steam turbine are highlighted in this paper.

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