CONSIDERATION OF MEDIUM-SPEED FOUR-STROKE ENGINES IN SHIP VIBRATION ANALYSES

Vibration problems were recently observed on several ships equipped with medium speed diesel engines. Measurements revealed a resonance condition between ignition frequency and H- type vibrations of the engines. As a consequence, the excitation forces transmitted from the engines to the foundations were drastically magnified. A procedure is described of how the natural frequency of the corresponding H-type modes can be predicted at the design stage. An example of the procedure is demonstrated on three vessels. The results obtained theoretically are verified by measurements. Generally, it was found that the calculated natural frequencies of the H-modes are in very good agreement with the measured values. It is shown that reliable results can only be obtained by considering the stiffness of the engine housing. Following this approach, a tool has been developed to predict the natural frequency of the H-type model shape of a medium-speed engine with a high degree of accuracy. In case of a danger of resonance, proposals can be given to detune the system, either by mounting the engine full- or semi-resiliently, or by changing the stiffness of the foundation.

  • Supplemental Notes:
    • Marine Technology & Transportation: ODRA 95, 1st Intl Conf on Marine Technology; 20-22 Sept 1995; Szczecin, Poland & MARTRANS 95, 1st Intl Conf on Marine Transport in the 21st Century; 30 Aug-1 Sept 1995; Plymouth, UK. Procs. Publ by Computational Mechanics Publications, UK, ISBN 1 853123307. Section 6, p 367 [8 p, 6 ref, 4 tab, 5 fig]
  • Authors:
    • Asmussen, I
    • Muller-Schmerl, A
  • Publication Date: 1995

Language

  • English

Subject/Index Terms

Filing Info

  • Accession Number: 00718871
  • Record Type: Publication
  • Source Agency: British Maritime Technology
  • Files: TRIS
  • Created Date: Mar 27 1996 12:00AM