Single-asperity failure mechanism driven by morphology and multiaxial loading using molecular dynamics simulation

Single-asperity contact behavior under multiaxial loading is of considerable effect between mechanical contact surfaces. Taking alpha-Fe as the paradigm material, a single-asperity model under multiaxial loading is established using molecular dynamics (MD) methods. The displacement behavior of the rigid plane, normal loading and asperity radius effects on the failure mechanism are analyzed. The results show that: (i) Normal loading affects the asperity normal deformation state, leading to different failure mechanisms in tangential slip. The failure tends to occur near the contact surface under low normal loading, but inside both the asperity and substrate under high normal loading. (ii) Different asperity radii may cause the asperities to be in different initial deformation states. The failure mode could be judged by combining the normal loading and asperity radius. The results provide detailed description of the asperity failure mechanism and could be applied in the analysis and design of contact interfaces.