Multiple normal loading-unloading cycles of a spherical contact under stick contact condition

The multiple normal loading-unloading process of an elastic-plastic sphere by a rigid flat is analyzed using finite element method for stick contact condition and both kinematic and isotropic hardening models. The behavior of the global contact parameters as well as the stress field within the sphere tip is presented for several loading cycles. It was found that under stick contact condition, secondary plastification occurs even after the second loading cycle and that the hardening model used has little effect on the loading-unloading process. The cyclic loading process gradually converges into elastic shakedown. [DOI: 10.1115/1.4002103] Keywords: spherical contact, elastic-plastic contact, contact condition, multiple loadings, hardening