An alternative force state map for shock absorbers

Automotive shock absorbers are commonly characterized by their force-velocity diagram. Nevertheless, mainly due to gas entrapped in the damper fluid, hysteretic effects can be observed on the characteristic curve. In order to improve the accuracy of the description and possible simulations, the restoring force method was used to describe the damper force. According to the restoring force method or equivalent force state mapping technique, the damper force is fitted as a non-parametric function of both velocity and displacement. However, it is shown for a damper under test that a more appropriate choice would be to use velocity and acceleration as independent variables instead of displacement and velocity for broadband excitation signals.