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Finite element method has been used for modal and vibration / stress analysis of a passenger vehicle. The study vehicle has been discretised taking into account the chassis elements, axles, suspension and tyres. The Lanczos method has been successfully used for the modal analysis. The power spectral density (p.s.d.) of acceleration of a track measured by using three height sensors has been fed as input to the tyres and the dynamic response of the vehicle in terms of acceleration and strain has been computed at all the nodes using finite element modeling and the random vibration concept. The experiments were carried out using piezo-electric accelerometers and strain gauges to measure the vibration and strain levels at critical points of the vehicle. The vibration and strain levels calculated through f.e.m. match well with the experimental values.

A vehicle's lateral performance and handling characteristics are most important while negotiating a turn. In this paper sensitivity analysis of lateral acceleration and yaw rate for front wheel steering vehicles is carried out in the frequency domain using the first order standard and first order logarithmic sensitivity functions. A simple two degree of freedom model is used for deriving amplitude ratio and phase angle for both yaw rate and lateral acceleration. Vehicle mass, yaw moment of inertia, front and rear tire cornering stiffnesses and distance from the front axle to the centre of gravity are the design variables considered. This study predicts that the strongest parameter is the location of the centre of gravity and the weakest parameters are mass and yaw moment of inertia.

A 3-degrees of freedom rigid body model has been developed to predict the directional response of a light passenger vehicle. An attempt has also been made to modify and use the finite element model developed for determining the vibration response of the vehicle to predict the directional response of the vehicle. The Newmark time integration scheme has been used as solver. The tyre properties such as lateral stiffness, cornering stiffness, self-aligning torque stiffness have been measured using the facilities of (CIRT) Central Institute of Road Transport, Pune. The simulation results of directional response of the vehicle in terms of roll angle, yaw rate and lateral acceleration for the sinusoidal and ramp steering inputs (applicable in tests such as the Slalom test and J-turn manoeuvre respectively) to the vehicle at constant speed have been presented.