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Predicting steering efforts at parking speed condition is critical to achieve ergonomically efficient steering system. The most important factor in calculating steering effort is the static friction torque of tires, which are affected by tire loads, kingpin axis geometry such as camber, caster and kingpin offset. In this research a multi-body approach to calculate steering effort and rack-bar force as a function of tire contact patch friction torque is proposed. For validation, the computed rack-bar force and steering effort are compared to the measured values obtained through actual vehicle test, and they showed good correlation.

In order to evaluate the crash-worthiness of a car, the dynamic response of the car body has to be correctly obtained at each level of car velocity. For the dynamic analysis, the dynamic properties of auto-body materials need to be identified for various strain rates. One of the typical high strain rate tensile tests is a split Hopkinson bar test. The present experiment has been carried out with a new split Hopkinson bar apparatus specially designed for the dynamic tensile test of sheet metals. The experiment provides stress-strain curves for various strain rates ranged from 2500 to 5000/sec. The experimental results from the both quasi-static and dynamic test are used to construct the Johnson-Cook equation as a constitutive relation, which can be applied to simulate the dynamic behavior of auto-body structures.