A contact force model with nonlinear compliance and residual indentation

The contact between two bodies is a complicated phenomenon in which the force and the relative position have nonlinear relations. Empirical results in the literature show that, in some mechanical systems such as biological tissues, the relation between the contact force and the indentation is characterized by the following three features: (i) continuity of the force at the time of collision, (ii) a Hertz-like nonlinear force-indentation curve, and (iii) nonzero indentation at the time of loss of contact force. The conventional Hunt-Crossley (HC) model does not capture the feature (iii) as the model makes the contact force and the indentation reach zero simultaneously. This paper proposes a compliant contact model based on a differential-algebraic equation that satisfies all three features. The behaviors of the model and the effect of the parameters in the model are investigated through numerical simulations.