Despite the relevance of wear in many engineering applications, our understanding of the wear process at the macroscopic scale still remains limited, and physically-motivated models predicting the wear volume are still missing. This is mostly due to the complexity of the problem, which is caused by the concurrent influence of surface geometry and roughness, material properties, microstructure, chemistry, and loading conditions on wear. Therefore, recent work in our group focused on simplified, but physical descriptions of adhesive wear at the single-asperity level under the assumption of non-interacting asperities [1,2,3]. In the present contribution, we expand this view to the interactions between multiple junctions formed by contacting asperities: When the junctions are closely-spaced, e.g., under high load, the debris formation mechanism might switch from a single-junction to a multi-junction process. Using molecular dynamics simulations, we first investigate these interactions on a range of model materials, including single crystals and polycrystalline structures. Using this, we derive an understanding of the influence of surface geometry and material properties and describe the multi-junction interactions in the framework of fracture mechanics. In the second step, we apply the insights from these simulations to numerical contact solutions using the boundary element method for rough, self-affine surfaces. Thereby, we upscale the results to realistic contact and junction geometries and systematically treat the influence of normal and tangential load.
 Aghababaei et al., Nat. Commun. 7 (2016)
 Aghababaei et al., PNAS 114 (2017)
 Frérot et al., J. Mech. Phys. Solids (2018)