ON DAMPING OF TORSIONAL VIBRATION IN A PROPULSION SYSTEM HAVING A FLUID DRIVE

In considering torsional vibration during the design of a Diesel propulsion system, precautions are taken to ensure either that resonance will not occur under operating conditions, or that there is adequate damping if it does occur. In general, there are two approaches available for making the necessary checks:--(i) classical modal analysis, and (ii) "distribution" of the damping. The main purpose of this paper is to demonstrate, by reference to an actual propulsion system which failed in service, that when a fluid drive is used there is no question of choice between these two approaches. The fluid coupling closely couples the principal modes, and classical modal analysis may lead to optimistic false conclusions; the second approach must be used despite the great difficulty in specifying, with any confidence, the distribution of the damping. Another objective of the paper is to present the theoretical argument in a concise way so as to show the relationship between the two approaches. The paper is presented under the main headings:--The Propulsion System; Steady Forced Torsional Vibration; Resonant Torsional Vibration in Principal Modes; Measured Values; Coupling of the Principal Modes; Conclusions.

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    • Paper for written discussion.
  • Corporate Authors:

    Institute of Marine Engineers

    Memorial Building, 76 Mark Lane
    London EC3R 7JN,   England 
  • Authors:
    • Bishop, RED
    • Price, W G
    • Tam, PKY
  • Publication Date: 1978

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Filing Info

  • Accession Number: 00189307
  • Record Type: Publication
  • Source Agency: British Ship Research Association
  • Report/Paper Numbers: Part 5
  • Files: TRIS
  • Created Date: Apr 25 1979 12:00AM