Date of Award

8-31-2018

Publication Type

Master Thesis

Degree Name

M.A.Sc.

Department

Mechanical, Automotive, and Materials Engineering

Keywords

NVH, Ride Comfort, Top Mount

Supervisor

Johrendt,, Jennifer

Rights

info:eu-repo/semantics/openAccess

Abstract

The scope of “Evaluation of alternative approach for suspension corner damping by the use of hydraulic top mounts” is the analysis of the benefit given by the implementation of a hydraulic mount as the top mount for a vehicle suspension system. The whole project is based on numerical simulations performed by means of MATLAB®/Simulink®. Therefore, the modelling of the selected hydraulic top mount by means of a system of springs, dampers and masses was the starting point of the project. Afterwards, the aforementioned hydraulic top mount model was inserted into a quarter car model and its performance was compared to that of an equivalent quarter car model employing a rubber top mount, instead. Therefore, the quarter car model with the rubber top mount represented the reference model to assess the performance of the new hydraulic top mount. In particular, both linear and nonlinear quarter car models were developed, the former were used to check the robustness of the model itself and the latter were used to carry out all the comparisons with the reference models. Different chirp signals were used as input for all the linear models, while random road and single asperity signals were employed as inputs for the nonlinear models. Furthermore, in order to explore the potential improvements that could be achieved by implementing the hydraulic top mount, a second arrangement for the relative position of the hydraulic top mount and the shock absorbed in the quarter car model was modelled and, then, tested. A slight better performance was recorded in the case of models containing the hydraulic top mount. Finally, for a better understanding of the characteristics of the hydraulic top mount, a Design of Experiments (DOE) that takes into account the parameters of the mount hydraulic components was carried out; DOE methodology allowed one to identify the most influential factors in the quarter car model performance. Additionally, the analysis of DOE results was employed as a starting point to perform a first optimization of the hydraulic top mount. The simulation carried out employing the optimized top mount showed a relevant improvement with respect to the base hydraulic top mount and, a fortiori, with respect to the rubber top mount case. Moreover, it was shown that the second arrangement for the hydraulic top mount in the quarter car model could give even better performance than the model with the standard arrangement.

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