Vibration Analyses of Marine Diesel Engines : 1st Report, Experimental Modal Analyses

Abstract

Experimental modal analyses are performed to investigate the dynamic characteristics of marine diesel engines. In order to increase the efficiency and accuracy of modal analysis measurements, the authors have developed a modal analysis system that has the capability of multichannel frequency response measurement by stepped sine excitation. By using this system, modal testings of a 6-cylinder engine on a test bed and the same type of engine on a board (including the double bottom of the engine room) were carried out. In this paper, the results of those experiments are presented. Also, an example of predicting the influence of stays on engine vibration behaviour using the modal synthesis method is described, which demonstrates the accuracy and suitability of these methods.