The Significance to Establish a Durability Model for an Automotive Ride

This paper presents the study of a relationship between objective vertical vibration and coil spring fatigue life under different road excitation to shorten suspension design process. Current development processes of vehicle suspension systems consist of many different stages of analysis and time consuming. Through this vertical vibration and durability characterisation, the vehicle ISO weighted vertical accelerations were used to describe fatigue life of coil spring. Strain signals from various roads were measured using a data acquisition and then converted into acceleration signal. The acceleration signals were then used as input to multibody suspension model for forces time history on spring and acceleration signal of sprung mass extraction. The acceleration signals were then processed for ISO weighted indexes while the force time history was used for coil spring fatigue life prediction respectively. It has been found that the rural road contributed the lowest fatigue life and the highest weighted vertical vibration index when compared to other road conditions. The measured strain predicted fatigue life were also possessed acceptable range when compared to the simulated force fatigue life using a conservative comparison method. The vertical weighted accelerations were plotted against the measured strain and simulated force fatigue life with a coefficient correlations more than 0.99. This model provides immediate prediction between vertical weighted acceleration and fatigue of spring to shorten automotive suspension development time frame.