A new approach for the determination of the Iwan density function in modeling friction contact

Friction between interfaces seriously affects the dynamics of structures with joints. An accurate description of the friction behavior, usually given in the form of hysteresis loops, is then a prerequisite for a successful prediction of the dynamics of joint structures. Driven by this demand, this paper proposes a new approach in the framework of the Iwan model to better simulate the nonlinear constitutive relationship of joints. The approach derives the Iwan density function from the contact pressure distribution on the joint interface, without having to assume it like traditional Iwan-type models. Following this, the corresponding force-displacement expressions can be obtained. The proposed approach is applied to two different contact geometries: sphere-on-sphere and flat-on-flat. For the spherical contact, comparisons between the simulated results and the analytical solutions available in the literature show perfect agreement. Moreover, the effectiveness of the approach in flat-to-flat contact is validated by comparing the simulated hysteresis loop with the experimental counterpart.