Ride comfort uncertainty analysis and reliability design of a passenger vehicle undergoing random road excitation

The vibration of a vehicle often causes discomfort, fatigue and even serious injury to passengers. Therefore, reducing vibration levels to a tolerable range is one of the most important goals in vehicle design. Since ride comfort is determined by road roughness and vehicle properties, the uncertainty of ride comfort results from the uncertainties of road roughness and vehicle property data. A quantitative measuring index of ride comfort defined by the International Standards Organization is employed in the present study. A general multi-body dynamics formulation is employed to obtain a dynamic response, and a statistical method employing the first order sensitivity information is used to evaluate the ride comfort uncertainty. The effects of individual and overall design variable uncertainties on the ride comfort uncertainty are investigated, and probability distributions of ride comfort are obtained for the reliability analysis and design of a vehicle.