Issue 78

V. I. Kolesikov et alii, Fracture and Structural Integrity, 78 (2026) 220-232; DOI: 10.3221/IGF-ESIS.78.13

I NTRODUCTION ccording to the contemporary literature [1, 2, 3, 4, 5], well adopted tribological models are typically based on: i) continuum contact mechanics (Hertzian, Greenwood-Williamson), ii) finite element wear modeling (Archard-type, energy-based), iii) molecular dynamics (MD) simulation of nanoscale friction and iv) Discrete Element Method (DEM) simulation of abrasive wear. A significant limitation inherent to all the aforementioned approaches is the use of averaged or homogenized material properties, which makes it difficult to account for crystallographic anisotropy at the scale of individual grains. However, the above models provide limited information regarding specific grains and slip systems where plastic deformation initiates. In addition, the local stress tensor remains undetermined near grain boundaries, while the deformation mismatches between adjacent grains can give rise to stress concentration at critical points [6, 7]. On the other hand, crystal plasticity (CP) simulations with the use of the DAMASK package focus primarily on microscopic deformation, microstructure evolution and damage, slip-system activation, crystalline lattice rotations, and multiphysics coupling. To the best of our knowledge, there is a lack of publications on solving tribological problems with the use of the DAMASK package [8]. This is governed by the fact that wear processes involve severe strain gradients, material removal, debris formation, and third-body dynamics, which cannot be solved with the use of the DAMASK. Since the DAMASK is aimed for calculations at mechanical equilibrium conditions, it lacks the following features: i) modeling friction, ii) determination of coefficient of friction, iii) simulation of slip between contacting surfaces, iv) simulation of wear, v) calculating heat generation during friction, etc. In contrast, the mechanical problems of materials under prescribed loading conditions can mostly be solved. Even though the DAMASK could not model i) tribological contact, ii) friction, iii) adhesion, iv) roughness, or v) wear, it is still valuable for studying the subsurface mechanical problems. The latter occurs, in particular, beneath a tribological contact zone. For doing so, microstructure-sensitive stress and strain fields induced under combined normal and tangential loads might be analyzed, while no friction or contact-mechanics effects are taken into account in explicit form. In real tribological contacts, a stick zone is formed prior to sliding. In doing so, asperities of mated surfaces do not slip relative to each other. Regardless of the fact that the DAMASK cannot simulate interfacial behavior, the subsurface stresses might be calculated at this pre-sliding stage. Local stresses might be very high beneath the contact surface, even exceeding the hardness of the material before onset of sliding. With the use of the DAMASK the following parameters might be simulated: i) accumulation of internal stresses, ii) formation of plastic zones, and iii) stress redistribution between grains up to the point when macroscopic slip begins; however, the sliding cannot not be modelled. The latter corresponds to the response of the subsurface layer during the initial stage of dry friction, when surfaces are loaded but not sliding yet. In addition, the underlying material may experience extreme stresses. Such subsurface processes are critical in practical applications like: i) brake pads, ii) friction clutches, iii) sliding guides, and iv) aerospace components subjected to rolling or dragging loads. These subsurface deformation mechanisms are of actual relevance when slip would initiate. In doing so, of particular interest are: i) location of early damaged zones, ii) stress redistribution between grains with activated slip systems, and iii) evolution of strain hardening, etc. In this paper, the CP simulations were employed to study the mechanics of perfectly bonded interfaces that are relevant to: i) coatings on metallic substrates, ii) dovetail blade–disk joints, iii) diffusion-bonded materials under application of combined normal and shear loads, etc. The latter represent the subsurface deformation processes that occur beneath tribological contact zones in their perfectly bonded (pre-sliding) regime. After running this conceptual study, authors intend to apply this methodology to description of more complex systems including high strength multilayer wear resistant coatings [9, 10, 11, 12]. It is noteworthy that multilayered metal materials have been already studied with the use of the DAMASK; however, quite different parameters were analyzed: i) representative volume elements (RVEs), ii) load conditions, iii) CP model, and iv) solver [13, 14, 15, 16]. M ATERIALS AND METHODS he details on reconstructing basic RVE as well as CP simulation have been described in our previous papers [17, 18]. In this study, we utilized the Dream 3D (v 6.5.171) and the DAMASK (v 3.0) open-source packages [19, 8, 20] for RVE reconstruction and CP modeling, respectively. The color maps from simulations were visualized with the use of ParaView software (v 6.0.1) [21]. Computations were carried out with the use of a Hewlett-Packard Z8 G4 Workstation equipped with two Xeon Gold 5118 CPUs (2.30 GHz) and 128 GB ECC RAM. A T

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