Truck suspension models

Synopsis

Laboratory experiments on an International ACCO 1810A truck rear suspension unit are used to assess the validity of mathematical models for the tyre and spring.   Best results are achieved with tyre and spring models that are non-linear, with separate, fixed loading and unloading curves joined by loading and unloading transitions.   The use of linear tyre models causes only a small degeneration in accuracy.   The best linear tyre model has an unloading curve set at 0.9 times the loading curve. Alternatively, a linear tyre model with a viscous damping coefficient of 0.015 kN/mm/sec gives reasonable results.   The accuracies achieved with linear models for the suspension spring appear to be unsatisfactory.   Details of the transition curves for both tyre and spring are unimportant provided that the base length (along the deformation axis) is small.