Predicting base Engine Vibrations using Flexible Multi Body Dynamics Simulation

Abstract

Predicting the vibratory response of a base engine is appealing as it can speed up the engine development cycle and cut down testing cost. However, there are concerns regarding predictability of base engine vibration simulation models due to various factors. This study attempts to investigate this predictability and gives more insights on what factors can affect it. In the presented work, the vibratory response of a base engine is predicted through a flexible Multi Body Dynamics simulation. Cylinder pressure excitation on the cylinder head and pistons, and reciprocating inertia excitation, are considered as inputs in this flexible Multi Body Dynamics simulation. Effects arising from overhead moving components and gear train, have been excluded from this study. The predicted vibratory response of the base engine at particular locations, is compared with the vibratory response as measured using accelerometers mounted at those locations, during testing. A reasonable level of correlation can be seen between simulation and testing. Measures that can be taken to improve this correlation are also discussed.