ELASTIC, VISCOUS AND FRICTION PHENOMENA BASED COMPUTATIONAL MODEL OF ENGINE MOUNT DYNAMICS

Paper i proceeding, 2008

Vehicle engine mounting system is a vibration control system that can be passive, semi-active or active. It isolates the noise and vibration, and also the transmitted forces to the vehicle structure. At present conventional rubber-metal mounts are widely used for engine mounting systems. Usually in vehicle models a linear parallel spring and viscous damper represent an engine mount. This model does not take care of the nonlinear behavior of the mount dynamics. In the present paper, a new computational model was developed suitable for prediction and analysis the nonlinear behavior of dynamic stiffness and damping for front and rear engine mounts of commercial vehicles under harmonic external excitations. Using the developed model the stiffness and damping of two different engine mounts have been estimated for the frequency range of 5-100 (Hz) and amplitude range of 0.025-2 (mm). It was found that the changes of stiffness of the mount are up to %32 with respect to amplitude and up to %29 with respect to frequency of excitation. Non-dimensional damping of the mount changes up to %88 with the change in amplitude and frequency of excitation. The computational model has been validated and verified against measurement data for harmonic excitations of conventional mounts. For different inputs of amplitude and frequency, the model shows admissible agreement with the measurement data. The tolerances of estimation of stiffness and damping regarding the measurement data are about %10. The developed computational mount model and obtained results can be used in complete vehicle dynamics analysis and in the design of semi-active and active engine mounts for commercial vehicles.