Analysis and Prediction of Engine Structure Vibration

The work described in this paper was undertaken as part of a program aimed at predicting engine noise and vibration characteristics at the design stage. The initial work was carried out on simplified two dimensional plate structures and a simple three dimensional model. Surface vibration and noise levels were predicted and compared with measured vibration levels and mode shapes are given for an in-line six cylinder diesel engine. The prediction of noise at the design stage relies upon the calculation of surface response levels. Supplementary tests on engine components to determine damping are reported. The approach to Force level simulation over a broad frequency band is also considered.