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Tuesday, May 12, 2020 | History

3 edition of Passive eddy-current damping as a means of vibration control in cryogenic turbomachinery found in the catalog.

Passive eddy-current damping as a means of vibration control in cryogenic turbomachinery

Cunningham, Robert E.

Passive eddy-current damping as a means of vibration control in cryogenic turbomachinery

by Cunningham, Robert E.

  • 27 Want to read
  • 14 Currently reading

Published by National Aeronautics and Space Administration, Scientific and Technical Information Branch, For sale by the National Technical Information Service,] in [Washington, D.C.], [Springfield, Va .
Written in English

    Subjects:
  • Damping (Mechanics),
  • Vibration (Aeronautics) -- Damping.,
  • Bearings.,
  • Cryogenics.,
  • Damping.,
  • Eddy currents.,
  • Rotor aerodynamics.,
  • Turbine pumps.

  • Edition Notes

    StatementRobert E. Cunningham.
    SeriesNASA technical paper -- 2562.
    ContributionsUnited States. National Aeronautics and Space Administration. Scientific and Technical Information Branch.
    The Physical Object
    FormatMicroform
    Pagination1 v.
    ID Numbers
    Open LibraryOL16116626M

      Seals control turbomachinery leakages, coolant flows and contribute to overall system rotordynamic stability. In many instances, sealing interfaces and coatings are sacrificial, like lubricants, giving up their integrity for the benefit of the :// The rig used for the modeling, the design and the experimental tests is an electrical spindle (picture reported in Figure 1) consisting of a shaft supported by two radial and one axial active magnetic bearings with cylindrical geometry and powered by an asynchronous high frequency electric mechanical ball bearings, with radial and axial airgaps equal to half of the levitation ones

    SDM Acoustic and Aerodynamic Loads • Monday, 23 April • hrs Active magnetic bearings consume much less power than conventional passive bearings, especially when power-minimizing controllers are employed. Several power-minimizing controllers have been proposed, such as variable bias controllers and switching controllers. In this paper, we present an appraisal of the power-minimizing control algorithms for active magnetic bearings in an attempt to

      Seals control turbomachinery leakages, coolant?ows and contribute to overall system rotordynamic stability. In many instances, sealing interfaces and coatings are sacri?cial, like lubricants, giving up their integrity for the bene?t of the component. They are Compared to eddy current (EC) probes, microwave sensors have a superior resolution and measurement range. Typically the sensors have an outer diameter between and 10 mm [17,31]. Many types of damage show just a small change in tip clearance, for example, blade root cracking is around – mm (small crack).


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Passive eddy-current damping as a means of vibration control in cryogenic turbomachinery by Cunningham, Robert E. Download PDF EPUB FB2

Passive eddy-current damping as a means of vibration control in cryogenic turbomachinery. By R. Cunningham. Abstract. Lateral shaft vibrations produced by a rotating unbalance weight were damped by means of eddy currents generated in copper conductors that were precessing cyclicly in the gap formed by the pole faces of C-shaped, permanent Get this from a library.

Passive eddy-current damping as a means of vibration control in cryogenic turbomachinery. [Robert E Cunningham; United States.

National Aeronautics and Space Administration. Scientific and Technical Information Branch,; Lewis Research Center.] Passive eddy-current damping as a means of vibration control in cryogenic turbomachinery. Washington, D.C.: National Aeronautics and Space Administration, Experimental damping coefficients varied from to N sec/m.

Reasonable agreement was noted for theoretical values of damping for these same assemblies. Values of damping coefficients varied from to N sec/m.

The results demonstrate that passive eddy-current damping is a viable candidate for vibration control in cryogenic This magnetic damping scheme functions due to the eddy currents that are generated in a conductive material when it is subjected to a time changing magnetic field.

Due to the circulation of these currents, a magnetic field is generated, which interacts with the applied field resulting in a force. Passive Eddy Current Damping as a Means of /Modeling-of-a-New-Active-Eddy-Current-Vibration. Experiments were conducted with a rotating test apparatus that eddy-current damping is a viable means to control to evaluate eddy-current damping as a means of reducing vibration in cryogenic turbomachinery.

Increased damping is lateral shaft vibrations, possible with designs that incorporate a greater number of   Cunningham, R.E.,"Passive eddy-current damping as a means of vibration control in cryogenic turbomachinery," NASA Technical Paper No. Google Scholar Fredreick, J.R. and Darlow, M.S.," Operation of an electromagnetic eddy-current damper with a supercritical shaft," ASME Journal of Vibration and Acoustics- Eddy Current Damping in Structures Article (PDF Available) in The Shock and Vibration Digest 36(6) November with 8, Reads How we measure 'reads' Cheah S.K.

and Sodano H.A., (). Novel eddy current damping mechanism for passive magnetic bearings, Journal of Vibration and Control 14(11): [ Links ] Cunningham R.E., ().

Passive eddy current damping as a means of vibration control in cryogenic turbomachinery, NASA Technical Paper number NASA-TP, Access No. ?script=sci_arttext&pid=S Robert E. Cunningham has written: 'The aviation art of Bob Cunningham' -- subject(s): Aeronautics in art 'Passive eddy-current damping as a means of vibration control in cryogenic turbomachinery Filed under: Damping (Mechanics) Effect of material damping and stress distribution on the resonant fatigue strength of parts / (Wright-Patterson Air Force Base, Ohio: Wright Air Development Center, Air Research and Development Command, U.S.

Air Force, ), by Egons R. Podnieks, Benjamin Joseph Lazan, and United States. Wright Air ?type=lcsubc&key=Internal friction&c=x. Passive eddy-current damping as a means of vibration control in cryogenic turbomachinery / By Robert E.

(Robert Ernest) Cunningham and Lewis Research Center. Abstract. Prepared at Lewis Research Center."February "es bibliographical references (p. 11).Mode of access: Internet With advantages of no mechanical contact, vacuum compatibility, oil-free, and high reliability, an eddy current damper has a great potential use in space.

In this paper, a passive magnetic damper system is developed by using the eddy current damping effect. The proposed eddy current damper utilizes a stationary permanent magnet and two conductive plates, and has significant performance than Q.

Pan et al. / Design and Damping Analysis of a New Eddy Current Damper for Aerospace Applications Latin American Journal of Solids and Structures 13 () Frequenc y (Hz) Particle damping (PD) is a passive mean of vibration control in which small metallic or ceramic particles are placed inside a cavity that attached to the primary structure at the place of high vibration amplitudes.

The kinetic energy of the primary structure is dissipated by non-elastic impact and friction between particles and :// Using this passive damping concept and the idea that the damping force is directly related to the velocity of the conductor, a new passive-active damping mechanism will be created.

This new damper will function by allowing the position of the magnet to change relative to the beam and thus allow the net velocity between the two to be maximized Current state-of-the-art in the control of AMB systems shows that PID controllers with associated filters are still the most widely used control strategy in industrial applications, however more advanced control algorithms, such as H ∞ and μ-synthesis, have gained significant interest in the research community over the last decade (1, 2).

Eddy Current 1. The principles of eddy current testing depend on the process of electromagnetic induction. This process includes a test coil through which vary or alternating current (AC) is passed.

A varying current flowing in a test coil produces a varying electromagnetic field around the coil, As shown in this diagram Amperage * # of coils= strength of magnetic field ://   In the aspect of NVH control of vehicles, the sound quality from silence, the NVH control technique of new energy automobile, the NVH control technology of the car body and chassis, the initiative vibration control technology and so on were Passive damping of composite blades using embedded piezoelectric modules or shape memory alloy wires: a comparative study.

F Bachmann 1, R de Oliveira 2, A Sigg 2, V Schnyder 3, T Delpero 1, R Jaehne 4, A Bergamini 4, V Michaud 2 and P Ermanni 1.

Published 28 June • IOP Publishing Ltd Smart Materials and Structures, Vol Number 7. Eddy current tuned mass damper (ECTMD), which employs the damping force generated by the relative movement of a non-magnetic conductive metal (such as copper or aluminum) through a magnetic field, is demonstrated to be an efficient way in structural vibration ://This book presents the papers from the 10th International Conference on Vibrations in Rotating Machinery.

This conference, first held inhas defined and redefined the state-of-the-art in the many aspects of vibration encountered in rotating ://  years has included progress on both passive (permanent magnet) and active (elec-tromagnet) systems. The improvements in bearing load capacity, stiffness and damping characteristics are traced in this report.

The trends in rotor size, rotational kinetic energy and improvements in active control system capabilities are also ://