  The detachment of material in an adhesive wear process is driven by a
fracture mechanism which is controlled by a critical length-scale. Previous
efforts in multi-asperity wear modeling have applied this microscopic process
to rough elastic contact. However, experimental data shows that the assumption
of purely elastic deformation at rough contact interfaces is unrealistic, and
that asperities in contact must deform plastically to accommodate the large
contact stresses. We therefore investigate the consequences of plastic
deformation on the macro-scale wear response using novel elastoplastic contact
simulations. The crack nucleation process at a rough contact interface is
analyzed in a comparative study with a classical $J_2$ plasticity approach and
a saturation plasticity model. We show that plastic residual deformations in
the $J_2$ model heighten the surface tensile stresses, leading to a higher
crack nucleation likelihood for contacts. This effect is shown to be stronger
when the material is more ductile. We also show that elastic interactions
between contacts can increase the likelihood of individual contacts nucleating
cracks, irrespective of the contact constitutive model. This is supported by a
statistical approach we develop based on a Greenwood--Williamson model modified
to take into account the elastic interactions between contacts and the shear
strength of the contact junction.
