The purpose of this paper is to introduce techniques used in experimental analysis and simulation of the internal resistance force in mechanical contact. We are presenting an idea and a method to separate the internal resistance into two force parts, the spring stiffness and the dissipative friction. This separation is based on the proven dependency for the projections of the phase angle between the displacement and acceleration of the periodic motion. By combining the Hilbert transform analysis with the phase relations of the simultaneously measured applied force and the vibration response we are able to estimate the nonlinear separated spring stiffness and dissipative friction force parts in the contact interference. Theoretical analysis and experimental measurements are presented as well as simulated verification results.