Mina M.S. Kaldas

Non-parametric modelling of damper top mounts

This paper details a new non-linear damper top-mount model, and the processes utilized to identify the constituent parameters. The damper top-mount model parameters are extracted from experimental data on commercial damper top mounts. The non-parametric restoring-force-mapping technique is used to construct the damper top-mount model. A damper top-mount model that consists of three elements, which are the non-linear elastic element, the non-linear friction element and the non-linear viscous element, is developed. The amplitude dependence of the top-mount characteristics is modelled by using the friction element and the elastic element, while the frequency dependence of the top mount is modelled by using the restoring-force-mapping technique. In order to obtain and optimize the required model parameters, a new procedure based on a two-stage optimization routine using two different sets of the measurement data for the amplitude-dependent parameters and the frequency-dependent parameters, is proposed. The model is validated by comparing the measured and simulated forces for three different damper top mounts. Good agreement between the measured force and the simulated force is obtained. Furthermore, the proposed model is found to be superior to the existing rubber isolator models.

Optimization of Damper Top Mount Characteristics to Improve Vehicle Ride Comfort and Harshness

A novel optimization technique for optimizing the damper top mount characteristics to improve vehicle ride comfort and harshness is developed. The proposed optimization technique employs a new combined objective function based on ride comfort, harshness, and impact harshness evaluation. A detailed and accurate damper top mount mathematical model is implemented inside a validated quarter vehicle model to provide a realistic simulation environment for the optimization study. The ride comfort and harshness of the quarter vehicle are evaluated by analyzing the body acceleration in different frequency ranges. In addition, the top mount deformation is considered as a penalty factor for the system performance. The influence of the ride comfort and harshness weighting parameters of the proposed objective function on the optimal damper top mount characteristics is studied. The dynamic stiffness of the damper top mount is used to describe the optimum damper top mount characteristics for different optimization case studies. The proposed optimization routine is able to find the optimum characteristics of the damper top mount which improve the ride comfort and the harshness performances together.