Constellation, le dépôt institutionnel de l'Université du Québec à Chicoutimi

Résumé

This study describes the analysis of suspension system and its lower arm. These analyses were specifically applied on lower suspension arm to determine its vibration and stress behaviour during its operation. The suspension system is one of the most important components of vehicle, which directly affects the safety, performance, noise level and style of it. The main objectives are to have less stress on lower suspension arm system as well as to reduce imposed load by optimization. The optimization of imposed load on lower suspension arm system is directly related to imposed force on the vehicle created by the road. This load has a direct effect on the value of imposed force on lower arm, where the lower arm force will be minimized by reducing the applied load. Hence, genetic algorithms for optimization and MATLAB optimization toolbar are used, as well as, specific M-file codes have been developed into MATLAB for optimization. By determining optimized design values of suspension system for reducing road force, it is possible to survey vibration condition of lower arm according to frequency respond of suspension system and its natural frequency. Therefore, frequency response of its acceleration has been determined according to the whole mass of suspension system. Using FFT technique and making transfer function for frequency response of suspension system, will present responded frequency of suspension system which is using for vibration analysis. For stress analysis, load condition of lower suspension arm system must be determined in advance. Hence, a typical model of McPherson suspension system has been selected for analysis. According to the road profile considered for analysis and the velocity of vehicle, it is possible to obtain both velocity and acceleration equations for whole components of McPherson suspension system. These values are used to determine dynamic force condition of lower arm suspension system during its operation. By using dynamic forces which are governing on lower arm of suspension system, in ABAQUS, the stress condition of lower arm can be determined during its operation.