SHIP VIBRATIONS DUE TO THE PROPULSION SYSTEM

The torsional-vibration behaviour of Diesel propulsion installations can now be predicted so well that it does not often cause difficulties, but there is an increasing need for remedial action against the jarring type of vibration, excited by the propulsion system, whose onset (unlike that of torsional vibration) is immediately obvious, particularly when it is accompanied by noise. The engine is usually regarded as the cause of this vibration, an assumption that is very often correct, but the propeller is another important cause. The Author (of Klockner-Humboldt-Deutz) examines the sources of this type of vibration, discussing in turn the inertia and gas forces in the engine, the fluctuations in thrust, torque, bending-moment, and transverse forces at the propeller, and the number of propeller blades. Excitations (seldom significant) by blade-vibration and by rotating parts other than the engine and propeller are also mentioned. The effects of engine- and propeller-excited vibration on the hull, and methods of combating this vibration, are explained and discussed, with practical examples. Among the aspects considered are: the need, in most cases, to rely on experience and certain established principles, rather than on finite-element predictions of vibration; identifying the excitation source; the absence, so far, of a "major breakthrough" in the prediction of vibration behaviour; excitation coefficients derived from dynamic propeller-data by the HSVA; difficulties in predicting whether a hull can withstand given excitation forces and moments without excessive vibration occurring; excitation by medium-speed and high-speed engines, and required stiffness of the engine foundations; flexible mountings for engines and for deckhouses and superstructures. Order from: BSRA as 48,907.

  • Corporate Authors:

    Schroedter (C) and Company

    Stubbenhuk 10
    Hamburg 11,   Germany 
  • Authors:
    • Tonndorf, J
  • Publication Date: 1978-3

Language

  • German

Media Info

  • Pagination: 6 p.
  • Serial:
    • HANSA
    • Volume: 115
    • Issue Number: 6
    • Publisher: Deutsche Bahn AG

Subject/Index Terms

Filing Info

  • Accession Number: 00180051
  • Record Type: Publication
  • Source Agency: British Ship Research Association
  • Files: TRIS
  • Created Date: Sep 14 1978 12:00AM