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Horizontal and vertical axle and cabin dampers are used on cars, trucks and busses to optimize the ride and safety and therefore represent vital components of the truck suspension. Nowadays there is a trend in industry for a longer component life featured by a shorter-term design. Therefore it becomes less obvious to have too many iterations in design with successive (long) durability test drives. Using the presented methodology the potential life damage for each critical component is identified from realistic road measurements and a life test is proposed which causes the same damage but in a relatively shorter period. This methodology was drawn up and validated during a European research program, Fatynamics.

A physical model is proposed to account for the hysteretic effects of automotive shock absorbers. Besides the oil compressibility, the compressibility of a variable gas phase in the shape of bubbles are the root of these dynamic effects. Due to the pressure dependent solubility of gas in the liquid the gas bubbles appear or disappear thus changing the compressibility characteristics. The model is used to identify the internal architecture of the damper, i.e. the valve parameters, and the hysteretic effects simultaneously. Some justifiable assumptions are introduced to estimate directly from damper force, piston displacement and velocity measurements.