Symmetric Contacts Research Articles

Effect of occlusal contact on TMJ loading during occlusion: An in silico study

Alterations in occlusal features may have significant consequences, ranging from dental aesthetics to health issues. Temporomandibular joint disorders (TMDs) are often associated with joint overload, and the correlation between occlusal features and TMDs has been thoroughly discussed. In current work, we introduced a novel stomatognathic model that aligns well with in vivo experimental measurements, specifically designed to decouple the impact of occlusal contact and periodontal ligament (PDL) negative feedback on temporomandibular joint (TMJ) loading. Utilizing an in-silico approach, the simulation analysis included six symmetric occlusal contact scenarios. Furthermore, a biomechanical lever model was employed to clarify the mechanical mechanism and investigate the multi-factorial effects of TMJ overload. These findings indicate that anterior shifts in the occlusal centre lead to increased TMJ loading, particularly in occlusal contact cases with anteroposterior changes. Considering the symmetrical distribution of occlusal contact, mediolateral alterations had a more modest effect on TMJ loading. Additionally, potential negative feedback activated by principal strain of periodontal could not only alleviate joint load but also diminish occlusal force. These investigations enhance our understanding of the intricate interactions between masticatory muscles, occlusal forces, and joint contact forces, thereby providing motivation for future comprehensive studies on TMJ biomechanical overload.

Impact of Rh, Ru, and Pd Leads and Contact Topologies on Performance of WSe2 FETs: A First Comparative Ab Initio Study.

2D field-effect transistors (FETs) fabricated with transition metal dichalcogenide (TMD) materials are a potential replacement for the silicon-based CMOS. However, the lack of advancement in p-type contact is also a key factor hindering TMD-based CMOS applications. The less investigated path towards improving electrical characteristics based on contact geometries with low contact resistance (RC) has also been established. Moreover, finding contact metals to reduce the RC is indeed one of the significant challenges in achieving the above goal. Our research provides the first comparative analysis of the three contact configurations for a WSe2 monolayer with different noble metals (Rh, Ru, and Pd) by employing ab initio density functional theory (DFT) and non-equilibrium Green's function (NEGF) methods. From the perspective of the contact topologies, the RC and minimum subthreshold slope (SSMIN) of all the conventional edge contacts are outperformed by the novel non-van der Waals (vdW) sandwich contacts. These non-vdW sandwich contacts reveal that their RC values are below 50 Ω∙μm, attributed to the narrow Schottky barrier widths (SBWs) and low Schottky barrier heights (SBHs). Not only are the RC values dramatically reduced by such novel contacts, but the SSMIN values are lower than 68 mV/dec. The new proposal offers the lowest RC and SSMIN, irrespective of the contact metals. Further considering the metal leads, the WSe2/Rh FETs based on the non-vdW sandwich contacts show a meager RC value of 33 Ω∙μm and an exceptional SSMIN of 63 mV/dec. The two calculated results present the smallest-ever values reported in our study, indicating that the non-vdW sandwich contacts with Rh leads can attain the best-case scenario. In contrast, the symmetric convex edge contacts with Pd leads cause the worst-case degradation, yielding an RC value of 213 Ω∙μm and an SSMIN value of 95 mV/dec. While all the WSe2/Ru FETs exhibit medium performances, the minimal shift in the transfer curves is interestingly advantageous to the circuit operation. Conclusively, the low-RC performances and the desirable SSMIN values are a combination of the contact geometries and metal leads. This innovation, achieved through noble metal leads in conjunction with the novel contact configurations, paves the way for a TMD-based CMOS with ultra-low RC and rapid switching speeds.

Impact damage testing based on high-speed continuous water jet aircraft coatings

When an aircraft passes through a rainy area at high speed, the coating on the front edge of the fuselage will be continuously eroded by raindrops, causing the coating to wear, crack or even peel off. This paper uses carbon fiber T300 material as the base material, and at the different impact speeds and impact numbers, water cutting equipment was used to simulate the erosion of the coating caused by the continuous impact of water droplets. The damage morphology of samples at different damage stages was observed by digital microscope and Scanning Electron Microscope (SEM), and the damage evolution curve was established to analyze and reveal the damage behavior and damage mechanism of rain erosion. The results show that the degree of damage experienced an increasing trend with the increase of impact numbers and speed, until circular peel damage was formed; no damage occurred during the incubation period, and the curvature of the damage evolution curve increased significantly after the expansion period and eventually showed a stable expansion trend. The mechanical properties of the coating material were the main influencing factors of its rain corrosion resistance. Moreover, the axially symmetric unsteady contact problem of droplets impacting the surface of a solid deformable body was studied. And the contact area was determined based on the iterative algorithm boundary positioning method. A mathematical model and closed mathematical formula describing the unsteady interaction between a droplet and a solid deformable obstacle were proposed.

Efficient and stable self-powered PbSe photodetectors via doping-induced asymmetric Cr electrodes modulation of surface work function

Conventional PbSe infrared photodetectors typically demands a substantial external electric field, posing challenges in energy-constrained environments. Self-powered photodetectors present a promising avenue for addressing such electricity-related challenges. Nevertheless, the inherent limitations of symmetric Schottky contacts in metal-semiconductor-metal (MSM) photodetectors constrain their self-powered performance, resulting in opposing photocurrents. Constructing asymmetric MSM structures usually requires intricate design or sustained external fields. In this study, we propose a novel contact engineering strategy based on iodine doping to modulate surface work functions of PbSe film. Utilizing Cr electrodes, we achieve Ohmic contact on the iodine-doped top surface of PbSe film and Schottky contact on the as-grown bottom surface. This approach establishes a self-powered PbSe infrared photodetector with an asymmetric top-bottom MSM structure. We comprehensively investigate contact engineering by investigating surface chemical states, elemental variations, and surface work functions variation. Remarkably, the photodetector demonstrates an exceptional zero-bias detectivity of 1.13 × 109 Jones, with an extremely low dark current of 3.67 pA, high Ilight/Idark ratio exceeding 104, and extremely short response times of less than 1 ms, respectively. Our work introduces a new strategy for modifying the band structure, contributing to the fabrication of high-performance self-powered photodetectors.

Соединение в шероховатой плоскости и осесимметричных контактах со специальным покрытием

Соединение в шероховатой плоскости и осесимметричных контактах со специальным покрытием

Asymmetric contact-induced selective doping of CVD-grown bilayer WS2 and its application in high-performance photodetection with an ultralow dark current.

Two-dimensional (2D) transition metal dichalcogenides (TMDs) are excellent candidates for high-performance optoelectronics due to their high carrier mobility, air stability and strong optical absorption. However, photodetectors made with monolayer TMDs often exhibit a high dark current, and thus, there is a scope for further improvement. Herein, we developed a 2D bilayer tungsten disulfide (WS2) based photodetector (PD) with asymmetric contacts that exhibits an exceptionally low dark current and high specific detectivity. High-quality and large-area monolayer and bilayer WS2 flakes were synthesized using a thermal chemical vapor deposition system. Compared to conventional symmetric contact electrodes, utilizing metal electrodes with higher and lower work functions relative to bilayer WS2 aids in achieving asymmetric lateral doping in the WS2 flakes. This doping asymmetry was confirmed through the photoluminescence spectral profile and Raman mapping analysis. With the asymmetric contacts on bilayer WS2, we find evidence of selective doping of electrons and holes near the Ti and Au contacts, respectively, while the WS2 region away from the contacts remains intrinsic. When compared with the symmetric contact case, the dark current in the WS2 PD with asymmetric (Au, Ti) contact decreases by an order of magnitude under reverse bias with a concomitant increase in the photocurrent, resulting in an improved on/off ratio of ∼105 and overall improved device performance under identical illumination conditions. We explained this improved performance based on the energy band alignment showing a unidirectional charge flow under light illumination. Our results indicate that the planar device structure and compatibility with current nanofabrication technologies can facilitate its integration into advanced chips for futuristic low-power optoelectronic and nanophotonic applications.

Friction in roller technological machines

The study is devoted to solving the problem of determining the patterns of friction stress distribution in the symmetric roll module contact zone. A mathematical model was developed that describes the patterns of friction stress distribution in the contact zone of roll modules. It was established that the ratio of friction stress to normal stress in the contact zone of roll modules is not constant and changes at each point of the contact zone. It was revealed that the ratio of friction stress to normal stress depends on external forces acting on the roll supports, geometric and kinematic parameters of the roll module, and deformation properties of the strip and roller coating.

Light curves from symmetric, polytropic contact binaries

ABSTRACT We study the structure of contact binaries assuming a polytropic relation between pressure and density, restricting ourselves to the case of equal-mass components, i.e. symmetric contact binaries. In this case, matter is at rest in the corotating reference frame making this problem far simpler than the general case of non-symmetric contact binaries. We compute these structures assuming values of the polytropic index of n = 0.0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, and 3.5 employing a self-consistent technique due to Hachisu. As a part of the results, we find the shape of their surfaces. While for the case of n = 3.5, such surfaces are very close to those corresponding to equipotentials of the restricted Lagrangian three-body problem, for lower n values the departure is remarkable. We propose a generalized function to fit these surfaces, which allows us to perform an accurate integration of the light curve due to the object. Then, for values of n > 0.0 we computed a family of light curves considering different inclinations and values for the width of the neck connecting the components (or equivalently, the fillout factor) of the pair. We compare our calculations with the solution found for the symmetric contact binary V803 Aquilae by employing the popular phoebe code, that assumes the above-mentioned Lagrangian equipotential surfaces. We conclude that considering polytropic structures leads to parameters that may be appreciably different from those deduced by assuming that their surfaces correspond to equipotentials of the restricted three-body problem.

Asymmetric Schottky contacts induced via localized ultrafast laser irradiation for ultrasensitive, self-powered, 2D photodetectors

Self-powered photodetectors hold great promise for addressing power-related challenges in the “Internet of Things (IoT)” era. However, the self-powered performances of a metal-semiconductor-metal (MSM) structure photodetector are inherently limited due to the presence of the symmetric Schottky contacts, leading to canceling photocurrents in opposite directions, while constructing an asymmetric MSM structure demands complicated design or sustained external fields. Herein, we propose a novel contact engineering strategy based on localized femtosecond (fs) laser irradiation, achieving an asymmetric band structure in an MSM-structure photodetector with pristine symmetric Schottky contacts. As a result, a MoS2 photodetector that exhibits exceptional photoresponse and self-powered performances is successfully fabricated. The device type transitions from a photoconductor to a photodiode, exhibiting a significant improvement in the rectification ratio from 1 to > 104. A comprehensive study on fs laser-based contact engineering is conducted by investigating atom diffusion, element variation, and Schottky barrier height variation. Notably, the photodetector demonstrates an exceptional zero-bias responsivity of 1.72 A/W, with a short circuit current of 37.2 nA and maximum output electric power of 1.67 nW. Our work provides a new strategy for modifying the energy band structure and facilitates the fabrication of high-performance self-powered photodetectors.

PHYSICAL AND MATHEMATICAL MODELING OF THE DISTRIBUTION OF LOAD FORCES ON THE FEMINAL COMPONENT OF AN ENDOPROSTHESIS OF THE HIP JOINT UNDER REAL CONDITIONS

Determination of the factors causing the development of aseptic instability of endoprosthesis components is one of the main tasks of modern traumatology and orthopedics. It is important from a scientific and medical point of view to carry out physical and mathematical modeling of the distribution of load forces and their moments on the femoral component of a hip endoprosthesis. The purpose of the study: to conduct a physical and mathematical modeling of the distribution of load forces on the femoral component of a hip endoprosthesis under real conditions of incomplete axially symmetrical contact of the femoral component of the endoprosthesis and the femur, when the surface of the lower end of the endoprosthesis is not in contact with the surface of the bone. In the work, mathematical modeling of the distribution of point load forces and their moments on the contact surface between the femoral endoprosthesis stem and the bone marrow canal of the femur in real conditions is carried out. For qualitative estimates of point distributions of the load force, based on the analysis of previous results, an estimated empirical formula was obtained for these distributions: g(λ,λ1)=Р(λ,λ1) / 140λ7/2, in which the pressure Р(λ,λ1) is taken in kilograms per square centimeter (kg/cm2), and the point force g(λ,λ1) is in kilograms (kg). It was determined that the best, from the point of view of minimizing the harmful mechanical impact of the prosthesis on the femur, is the situation when the length of the prosthesis stem is not less than half the length of the femur (λ≥0.5). In this case, the values of the point load forces do not exceed 0.1 kg, at least for the length of the area of real contact, which is not less than half the length of the prosthesis stem (λ1≥0.5λ). It has been proven that the use of a prosthesis stem that is less than a third of the length of the femur is not advisable. Since already at the length of the prosthesis stem, which is 30 % of the length of the femur (λ=0.3), point loads increase rapidly and can reach from 0.55 to 1.5 kg depending on the length of the contact area. Such point loads are undesirable for the femur in the area of contact with the prosthesis in terms of the integrity of the femur.

Deviations and similarities between landauer’s approach and the multi-electronic classical master equation in describing nanoscale transport

In this work, we show that the classical master equation (CME) treatment—with the rates obtained via the Fermi golden rule—and the elastic scattering (ES) approach give the same results for a system composed of two states/one level when considering the approximations of (i) non-interacting limit, i.e., the electronic structure of the N-particle states remains frozen even in the presence of an extra particle, (ii) wide-band limit (WBL) approximation, and (iii) excited states are discarded. Although the predictions of these two approaches ‘deviate’ from each other when more states and/or levels are considered, under the conditions of strong coupling limit and symmetric contacts both treatments capture the same physics involved in the transport process. For other situations—such as asymmetric coupling and/or weak metal–organic coupling—the predictions of these two theories do not agree with each other. Finally, even considering that in our treatment the electronic structure of the system is described at a tight binding level, the corresponding results clearly show the situations where the similarities and differences between the CME and ES approaches can be identified.

Research on the Filling Process of Ultraviolet Nanoimprint Lithography with High-Resolution Stamps

With the rapid development of the semiconductor industry, the feature size of integrated circuits (ICs) is continuously getting smaller and smaller. Although traditional optical lithography and extreme ultraviolet (EUV) lithography can fabricate products with 5-nm feature size, the production cost is quite high. As a candidate of next-generation lithography, ultraviolet nanoimprint lithography (UV-NIL) can also achieve high-resolution imprints at a lower cost. Based on contact mechanics, the filling mechanism and imprint quality of UV-NIL were examined using high-resolution stamps with different feature sizes of 3 nm, 4 nm, and 5 nm. It was found that UV-NIL could successfully replicate patterns with feature sizes down to 3 nm; however, the imprinting process was more complicated. Among the selected nine stamps, the replications of 4-nm and 5-nm feature sizes had a relatively uniform residual layer and a symmetric contact pressure, whereas the replications of 3-nm feature size had an asymmetric contact pressure, resulting in an asymmetric residual layer. In order to obtain a more uniform residual layer with higher-quality imprinting, the pressure applied to the left and right sides of a stamp should be appropriately changed. The pattern density of a stamp had a certain influence on the contact pressure. As the pattern density increased, the contact pressure tended to be uniform; however, when the pattern density exceeded 0.5, the situation became worse. This research can provide guidance for promoting the development of UV-NIL in the direction of high-resolution pattern replication.

Convergence of the one-dimensional contact process with two types of particles and priority

We consider a symmetric finite-range contact process on Z with two types of particles (or infections), which propagate according to the same supercritical rate and die (or heal) at rate 1. Particles of type 1 can enter any site in (−∞,0] that is empty or occupied by a particle of type 2 and, analogously, particles of type 2 can enter any site in [1,∞) that is empty or occupied by a particle of type 1. Also, at most one particle can occupy each site. We prove that the process with initial configuration 1(−∞,0]+21[1,∞) converges in distribution to an invariant measure different from the non trivial invariant measure of the classic contact process. In addition, we prove that for any initial configuration the process converges to a convex combination of four invariant measures.

An Indium Synthetic Etioporphyrin for Organic Electronics: Aggregation and Photoconductivity in Thin Films.

A new complex of indium(III)chloride with etioporphyrin-I was synthesized and characterized. As with naturally occurring extraligated etioporphyrins, the InCl-EtioP-I spectrum in solution has a very strong B-band and a more than an order of magnitude weaker Q-band, but this difference diminishes in solid films of InCl-EtioP-I obtained by thermal evaporation in vacuum. In a solid, molecules have a tight convex-convex arrangement in a 2D double layered structure with interplane distance of 3.066 Å. The conductivity of films can easily be activated by the action of temperature or light. In the cells with symmetrical lateral contacts the photocurrent exceeds the dark current by about three orders of magnitude, with the contribution of photons in the Q-band range being greater than expected from the experimental or calculated absorption spectrum. The Q-bands contribute significantly to the photovoltaic effect in the ITO/InCl-EtioP-I/Al sandwich cells. Such cells show an untypically strong signal in the photodiode regime, which yields the spectral detectivity of 10^12 Jones.

The occurrence of anthophyllite–phlogopite-bearing schist in the Seridó belt, northeastern Brazil: Geological significance and potential guide of prospecting for gold and emerald deposits

In the Bonfim W–Mo and Au–Bi–Te skarn deposit, Northeastern Brazil, Archean metamafic–ultramafic rocks are similar to those found in greenstone belt sequences worldwide. The Bonfim emerald deposit comprises metric layers of lenticular-shaped phlogopite-rich schist developed at the symmetrical contacts between metamafic–ultramafic rocks and Be-rich granite intrusions. They formed near these rocks by metasomatic fluids emanating from granitic magma. Metasomatism also transformed the marble and schists into skarns at the marble–schist contact and within the marble. This contribution describes the drill cores containing Mg-rich schist in the Neoproterozoic metapelitic sequence. Detailed petrographic observations and geochemical analysis reveal that it contains phlogopite, anthophyllite, fuchsite, and anomalous Cr–Ni–V–Co–Sc contents. These characteristics contrast those of the common schists at Bonfim or regionally and indicate a probable komatiitic affinity. The anthophyllite–phlogopite-bearing schist contains a metamorphic paragenesis of phlogopite + anthophyllite + garnet + tourmaline + zircon + monazite + plagioclase + quartz, followed by two successive retrograde metasomatic parageneses comprising (i) clinozoisite–zoisite + apatite and (ii) white mica (±fuchsite) + clinochlore + quartz. It exhibits a peculiar texture containing prismatic pseudomorphs (1–7 mm long) composed of anthophyllite, clinozoisite–zoisite, and white mica. The relict orthogonal cleavage suggests that they could represent preexistent Mg-rich pyroxene. Similar to the common schist in Bonfim, the anthophyllite–phlogopite-bearing schist near the skarns is metasomatically converted in places into actinolite–anthophyllite–phlogopite-bearing schist. The anthophyllite–phlogopite-bearing schist contains phlogopite and biotite with low Fe/(Fe + Mg) (between 0.2 and 0.4) and anthophyllite with a composition close to Mg5Fe2Si8O22(OH)2 (MgO approximately 22 wt% and Al2O3 <0.7 wt%). In the actinolite–anthophyllite–phlogopite-bearing schist, the metasomatically formed amphibole has a composition varying from actinolite to magnesiohornblende with a high MgO (>16.5 wt%). The whole-rock geochemical analyses of three representative samples indicate that the anthophyllite–phlogopite-bearing schist contains high MgO (approximately 15%), Cr (up to 574 ppm), and Ni (up to 237 ppm) contents, besides V (up to 198 ppm), Co (up to 51 ppm), and Sc (up to 25 ppm). The anthophyllite–phlogopite-bearing schist has higher MgO, K2O, S, Cr, Co, Ni, and Rb contents, and lower Na2O, P2O5, Zn, Sr, Zr, and Pb contents than the average composition of the Seridó regional schist. The 87Sr/86Sr ratio in two representative samples of the Bonfim schists revealed that the anthophyllite–phlogopite-bearing schist has higher ratio (0.89455) than the enclosing common schist (0.74514), indicating distinct ages of the source rocks for the sedimentary protolith of these two schists, with evidence for an older age of the former source. The original sediments of the anthophyllite–phlogopite-bearing schist could have had an Archean komatiitic source (e.g., komatiitic basalt, peridotite, websterite or pyroxenite), as indicated by the Mg-rich metamorphic minerals (phlogopite and anthophyllite), Cr–K-rich metasomatic ones (fuchsite), and the peculiar MgO, Cr, Ni, Co, Sc, and K2O contents. This source could be part of an Archean greenstone belt now dismantled and/or removed by tectonic and erosion processes. Alternatively, the Mg-rich schist could be a remnant of the upper sedimentary unit of such an ancient rock sequence. The unusual schist could potentially guide gold and emerald deposit prospecting in the region.

Light–induced transition of charged carrier transport in symmetric metal–semiconductor–metal contacts

Metal–semiconductor (M–S) contact is a basic element in semiconductor integrated circuit. Recent studies on photodetectors extensively focus on M–S contact owing to the easy fabrication and superior performance. Here, we report a light–induced transition of charged carrier transport in planar Cu/Si–doped GaAs single crystal (Si:GaAs) symmetric double Schottky contacts. Different from conventional photodetector, illumination not only gains the carrier concentration but also changes the charged carrier transport mechanism at Cu/Si:GaAs contact. The light-induced transition of charged carrier transport is reflected by the change of shape of current–voltage (I–V) curve caused by illumination. By the construction of theoretical model and its fitting to experimental data, we point out that carrier transport mechanism at Cu/Si:GaAs contact changes from tunneling effect to thermionic emission by illumination. Among that, photovoltaic effect is the crucial driving force. This study presents a novel mechanism for converting optical signal to electrical signal by tailoring Schottky contact in photodetector, which provide a design prototype to new–type optoelectronic device.

A grasp planning algorithm under uneven contact point distribution scenario for space non-cooperative target capture

The contact point configuration should be carefully chosen to ensure a stable capture, especially for the non-cooperative target capture mission using multi-armed spacecraft. In this work scenario, the contact points on the base and on the arms are distributed on the opposite side of the target. Otherwise, large forces will be needed. To cope with this problem, an uneven-oriented distribution union criterion is proposed. The union criterion contains a virtual symmetrical criterion and a geometry criterion. The virtual symmetrical contact point criterion is derived from the proof of the force closure principle using computational geometry to ensure a stable grasp, and the geometry criterion is calculated by the volume of the minimum polyhedron formed by the contact points to get a wide-range distribution. To further accelerate the optimization rate and enhance the global search ability, a line array modeling method and a continuous-discrete global search algorithm are proposed. The line array modeling method reduces the workload of calculating the descent direction and the gradient available, while the continuous-discrete global search algorithm reducing the optimization dimension. Then a highly efficient grasping is achieved and the corresponding contact point is calculated. Finally, an exhaustive verification is conducted to numerically analyze the disturbance resistance ability, and simulation results demonstrate the effectiveness of the proposed algorithms.

Contributions of symmetric metal contacts on liquid exfoliation 2D-MoS2 flakes based MSM photodetector by spray pyrolysis: a CVD-free technique

Contributions of symmetric metal contacts on liquid exfoliation 2D-MoS2 flakes based MSM photodetector by spray pyrolysis: a CVD-free technique

Two-dimensional SiC Schottky junctions with symmetrical and asymmetrical metal electrode contacts

Four symmetrical and six asymmetrical Schottky contacts in the metal–semiconductor-metal structures were constructed by using two-dimensional (2D) SiC material as channel and four metal materials (Ag, Al, Au, Pd) as electrodes. On the basis of density functional theory and ab initio calculation method, devices’ transmission spectra, current–voltage characteristics, local density of states, rectification ratio, current–temperature characteristics and negative differential thermoelectric resistance were studied. The results show that Schottky contact is formed between the four metal materials and the 2D SiC. Partially asymmetrical metal electrode structure devices have excellent rectification characteristics. The device has the optimal rectification characteristics with a rectification ratio of 747 when Pd and Au are used as asymmetrical electrodes. Moreover, the temperature dependence of thermionic excitation transport has a key influence on the rectification properties of the device. The rectification ratio reaches to 2100 around 200 K in the junction of Pd–SiC–Au. A key finding is that the negative differential thermoelectric resistance can be generated in Pd–SiC–Au device when a temperature difference applied between two electrodes without external bias voltage. The results of this study can provide theoretical reference for the subsequent design of transistors and other device based on 2D SiC material.

New Tribological Aspects in the Micro-Areas of the Symmetric Rolling-Sliding Contact

The study of wear that occurs during operation in the wheel–rail assembly is a difficult process to analyze. The phenomena that accompany the wear process are extremely complex and involve many factors, which vary greatly over different periods of time and at different times of wheel–rail contact. Estimating the behavior of the system and its wear in operation is difficult to obtain. However, for common engineering applications, for which the determining factors, such as road profile, load, skid, speed and weather conditions, are known, useful results can be obtained by laboratory tests or by numerical simulation. The article aims to model the complex phenomena that take place in the rail wheel system, taking into account the impact that most essential operational factors have. For this, the Finite Element Method (FEM) is used, thus, trying to explain the wear mechanisms of the wheel–rail system. The obtained results are verified in the laboratory. The main observation in the paper refers to the fact that in the areas of maximum stress and deformation, cracks appear at the micro scale. FEM proved to be a method that can predict the appearance of these microcracks, the experimental results validating the numerical experiments. The research offers results that can prove to be of great importance in practice, for the analysis and improvement of railway safety.