Engine Shake is a low frequency phenomenon which causes vehicle vibration mainly in vertical direction leading to discomfort of the driver/passenger. This is caused by excitation due to small irregularities on smooth road surface. Engine mounting system design plays an important role in the Shake performance of the vehicle. This paper describes the Multi Body Dynamics (MBD) modeling and simulation study of the vehicle to analyze the Shake performance using Design of Experiments (DOE) approach.
In the study, a 16 DOF configuration system model of the vehicle system is built using Multi Body Dynamic (MBD) simulation software ADAMS. The effect of change in Engine bush stiffness and damping on Floor displacement has been analyzed by carrying out DOE study using ADAMS. This is done to optimize the Engine bush parameters for improved Shake performance of the vehicle.
Static equilibrium analysis is done on MBD model to check the correct load distribution in the vehicle according to test condition. Rigid body modes analysis of the MBD model provides information regarding the vehicle body and engine rigid modes (6 in number each). The input loads for Shake test is given as constant amplitude sine sweep excitation at Tire contact patch through actuators. The MBD model is correlated with test results from four poster shaker test for Wheel center acceleration (input) and Floor displacement (output). After MBD model validation, Design Study and DOE iterations are carried out to minimize the Floor vibration.
The process methodology depicted in this paper is useful in the concept design and development stage of the vehicle. It provides design direction for achieving better Shake performance and reduces the physical effort and time for testing the Shake performance of the vehicle for various Engine bush design specifications.