Finite element analysis on tangential spherical contact considering both yield plateau and strain hardening characteristics under a pre-sliding condition

The plastic characteristics with yield plateau and strain hardening are typical in annealed or normalized alloys, which are widely applied in some bracing and sealing assemblies. However, the yield plateau characteristic has not been well considered in elastoplastic contact issues. Based on a developed three-phase constitutive model, this work used a finite element method to investigate tangential spherical contact under a pre-sliding condition and focused on the impacts of material parameters on contact behaviors. Results demonstrated that the hemisphere more prone to higher plastic deformations corresponds to a more significant decline of normal force, softening of tangential stiffness, and junction growth; a new empirical formulation of tangential force versus tangential displacement has been presented; the junction growth is attributed to the plastic strain increments of the nodes inside the original junction.