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The contact problem with adhesion for a functionally graded coated half-space indented by a rigid spherical punch is considered. The whole contact region is stick assuming the interfacial friction ...

In the process of electromagnetic launching (EML), armature-rail contact is affected by the start-up contact. Because the location of the pulse current flowing into the armature is determined by that of the start-up contact region, the distributions of the current and electromagnetic force (EMF) in the armature are affected by the start-up contact. In this paper, the start-up contact between the conventional C-armature and rail is analyzed. Additionally, the distributions of the current flow and EMF in the armature are analyzed. The EMF resulting from the electromagnetic analysis is transferred to the structural analysis via a method of electromagnetic-structure coupling, and the distribution of the armature-rail contact pressure is acquired. Some armature contact parameters and the concept of the armature contact efficiency are proposed. The relationships between the contact parameters and the contact efficiencies of armatures with different lengths are acquired based on a series of simulations. To improve the contact efficiency of the armature, a method called “reverse loading” is presented to design an armature with a new profile. The traditional straight armature is replaced with a curved armature, and the results show that the contact efficiency of the armature with the curved profile is greatly improved.

In this letter, we report high-performance p-GaN HEMTs on Si with robust gate operation. For the first time, the preserved OFF-state drain blocking capability has been demonstrated in p-GaN HEMTs after forward gate breakdown. Benefitting from the reduced metal/p-GaN contact region, the gate breakdown was limited to take place only at the metal/p-GaN junction, with the p-GaN/AlGaN/GaN junction intact. The device shows state-of-the-art characteristics with a large threshold voltage of 1.75 V at ${I}_{\text {D}}$ of $100~\mu \text{A}$ /mm (2.3 V by linear extrapolation), a high maximum drain current of 610 mA/mm at ${V}_{\text {GS}}$ of 8 V, a low specific ON-resistance of 1.8 $\text{m}\Omega \cdot \text {cm}^{{2}}$ , and a high breakdown voltage of 1100 V defined at ${I} _{\text {D}}$ of $1~\mu \text{A}$ /mm with grounded substrate.

Within the framework of the anisotropic theory of elasticity, a three-dimensional contact problem of interaction of two massive transversely isotropic bodies, whose dimensions substantially exceed the size of the contact region, is investigated. In this case, the isotropy planes of contacting elastic bodies are mutually perpendicular. Exact and numerical solutions of the problem are determined. Calculations for various transversely isotropic materials are carried out.

Several methods have been investigated to analyze the penetration into oocyte membrane. Among them, micro-electromechanical system technologies have substantial potentials for Intracytoplasmic sperm injection (ICSI) or other penetration applications. In this paper, a novel method has been proposed for penetration into the bio-membrane by arrow and bow concept utilizing a designed MEMS actuator device. Thus, studying the mechanical properties of oocyte membrane is of great importance in this study. In this regard, in order to have a better understanding of the amount of the required force for penetration, failure stress and distribution of stress in contact region would be needed. Here, in the first step, the existing models are reviewed and their shortcomings for analyzing the contact region are discussed. Then, the ICSI process is simulated with finite element method (FEM) in ANSYS-APDL software. Finally by neglecting the plastic deformation of the membrane, its failure stress, Neo-Hookean and Mooney-Rivlin parameters are obtained. Eventually, the required needle velocity for penetration and its related effects after impact has been explored by ANSYS LS-DYNA software.

Please cite this article as: A. Romero, C. Jiménez, J. González, P. López-Varo, M.J. Deen, J.A. Jiménez-Tejada, Compact modeling of the effects of illumination on the contact region of organic phototransistors, Organic Electronics, (2019), 70, 113-121., A good modeling of degrading effects in an electronic device, such as the contact region of organic phototransistors (OPTs), can be favorably used to better describe and optimize the performance of the whole device. Furthermore, a proper design of the contacts can enhance the exciton dissociation and the extraction of photogenerated charge in the device. In this work, a compact model for OPTs is developed. This model is valid for all the operation regimes of the transistors. It includes a model for the contact region of the device that incorporates the effects of illumination. The compact model and the contact region model are validated with published experimental data from several OPTs under different illumination conditions. The tool used to validate the model is an evolutionary parameter extraction procedure developed in a previous work. The results show that both photoconductive and photovoltaic effects impact the intrinsic region of the transistor, as well as the electrical behavior of the contact region. The parameters used in the contact region model are linked to these photovoltaic and photoconductive effects., This work was supported by projects MAT2016-76892-C3-3-R and TIN2015-67020-P funded by the Spanish Government and European Regional Development Funds (ERDF) and by “Beca de Iniciación a la Investigación para estudiantes de Grado” given by the University of Granada.

A study has been made of the problem on the process of formation of a zone of higher-than-average permeability with a moving boundary in an initially low-permeability porous medium (problem on hydraulic fracturing of a bed) in a three-dimensional formulation. A characteristic feature of the three-dimensional problem was the taking into account the existence of two zones (zone with a regular permeability and the destruction zone) in the porous medium, whose contact region was determined using the condition of mass balance on the moving boundary. Special features fundamental to the process of mass transfer in such filtration-inhomogeneous porous media have been revealed and analyzed.

International audience; In this paper a spring-like micromechanical contact model is proposed, aiming to describe the mechanical behavior of two rough surfaces in no-sliding contact under a closure pressure. The contact region between two elastic bodies is described as a thin damaged interphase characterized by the occurrence of non-interacting penny-shaped cracks (internal cracks). By combining a homogenization approach and an asymptotic technique, tangential and normal equivalent contact stiffnesses are consistently derived. An analytical description of evolving contact and no-contact areas with respect to the closure pressure is also provided, resulting consistent with theoretical Hertz-based asymptotic predictions and in good agreement with available numerical estimates. Proposed model has been successfully validated through comparisons with some theoretical and experimental results available in literature, as well as with other well-established modeling approaches. Finally, the influence of main model parameters is addressed, proving also the model capability to catch the experimentally-observed dependence of the tangent-to-normal contact stiffness ratio on the closure pressure.

The paper describes the results of brake dynamometer experiments conducted to evaluate the influence of the tread temperature caused by tread braking on the wear rate of railway wheel tread. Employing a full-scale tread brake dynamometer composed of a brake block, a wheel, and a railwheel, wheel-rail rolling contact was imposed on the wheel tread surface heated under several braking scenarios. In dynamometer tests simulating the braking patterns of an actual vehicle exposed to unexpected hollow tread wear, no tread wear was observed after repetitive station stop braking, whereas tread wear was observed only for the rolling contact region after repetitive holding braking for load cases in which the internal tread temperature reached 300 °C. The wear rate of the rolling contact region was determined for various temperatures by performing experiments in which rolling contact was imposed at a constant tread temperature. The wear rate of the wheel tread increased rapidly with temperature at the tread surface for internal temperatures of 200 °C–300 °C. The wear volume obtained in the experiment was converted and generalized to determine the temperature dependence of the wear rate of the wheel tread as a function of the travel distance. The surface temperature of the tread and the internal temperature distribution were computed by FEM. The maximum temperature on the tread surface was estimated to range from 240 °C to 380 °C. The hollow wear of tread-braked railway wheels is primarily attributed to plastic deformation of the tread surface caused by hot rolling, i.e., rolling under a softened state with an increased temperature of the wheel steel on the tread surface. Verification of thermally activated process using Arrhenius equation confirms this conclusion.

Spontaneous ignition of compressed hydrogen release through a length of tube with different internal geometries is numerically investigated using our previously developed model. Four types of internal geometries are considered: local contraction, local enlargement, abrupt contraction and abrupt enlargement. The presence of internal geometries was found to significantly increase the propensity to spontaneous ignition. Shock reflections from the surfaces of the internal geometries and the subsequent shock interactions further increase the temperature of the combustible mixture at the contact region. The presence of the internal geometry stimulates turbulence enhanced mixing between the shock-heated air and the escaping hydrogen, resulting in the formation of more flammable mixture. It was also found that forward-facing vertical planes are more likely to cause spontaneous ignition by producing the highest heating to the flammable mixture than backward-facing vertical planes.

We show that significant reduction of sliding friction can be achieved between a rigid surface and a flat elastic surface by spatial variation in stiffness of the latter. This reduction in friction during sliding occurs due to an "auto-roughening" phenomenon in which a fully connected contact region breaks into partial contact. An elastomer, poly(dimethylsiloxane) (PDMS), was used to fabricate nominally flat surfaces with regions of two different stiffness, achieved by using two different concentrations of the cross-linker. Both experiments and finite element simulation show that, for sufficiently high friction and low normal load, the real contact area between a rigid indenter and a surface with spatially varying stiffness is reduced significantly due to auto-roughening. The finite element model also shows how the auto-roughening depends on the properties and geometry of interfacial structures, resulting in reduced overall friction.

The problem of sliding of a spherical indenter on a viscoelastic foundation is solved in a quasistatic formulation taking account the forces of adhesive attraction which are considered different at the entrance to and exit from the contact region due to changes in the surface properties during the interaction. It is found that the contact characteristics and the frictional force due to the imperfect elasticity of the foundation depend on the surface and bulk properties of the materials of the interacting bodies and the interaction conditions (load, velocity, etc.).

The wear damage mechanisms occurring in the tribological pair bronze (CuSn12)-quenched and tempered steel (42CrMo4V) frequently used as reference materials for worm gearing power transmissions were investigated. Lubricated rolling sliding tests in the disk-on-disk configuration were performed. Different radial loads were applied in order to reach in the contact region Hertzian pressures close to the allowable design limit for bronze. The relative sliding speed was set to a level typical of screw-worm wheel transmissions. The tests were conducted up to a sliding distance of about 1800 km and periodically interrupted for measuring the specimen's weight loss and for inspecting the surface modifications. At the end of the test, the wear curves (specific weight loss vs. sliding distance) were built up and the surface damage was analyzed by means of optical and scanning electron microscopy. Different damage phenomena as scoring, pitting, spalling were identified, whose severity depends on the applied load. Microstructural features, i.e. the interdendritic phase, strongly dictate the subsurface crack path and crack branching .

The flowing of the injection current in Pb1 − xSnxTe:In structures (x ≥ 0.3) with various metal contacts at the temperature of helium is considered. The current-voltage characteristics (CVCs) of the structures in the dark and when they are illuminated from the blackbody model are given. It is found that the CVCs depend on the materials of the metal contact. The localized state density distribution over the forbidden band in structures with various contacts is given and the influence of the contact region and localized states on the CVC is discussed. The problems of constructing photodetectors with optimum threshold characteristics are discussed.

In this paper, studies on “quasi-static” region of ohmic-contact behavior for MEMS switches under low contact force and low current conditions were carried out. Random telegraph signals (RTS) observed during the transition period were carefully investigated. It is found that RTS in transition region could be consistently identified by multiple characteristic time constants. The RTS behavior with multiple time constants suggests that different contact mechanisms could involve during “quasi-static” contact region. A dominant mechanism with time constant of ~1 ms was observed for the Au-to-Au contacts used in this study.

Current-voltage characteristics of the In-ZnGa2Se4-In structure have been studied in the temperature range of 90–335 K. Based on the data calculated for the concentration of three trap types in ZnGa2Se4, the values Nt = 1.4 × 1013, 8.2 × 1012, and 2.6 × 1012 cm−3 are obtained. The contact region transparency Dk*= 10−5, surface recombination velocity Sk = 0.65 m/s, and carrier lifetime τ = 1.5 × 10−4 s were determined. It was found that the current transmission mechanism in electric fields weaker than 103 V/cm is caused by monopolar carrier injection.

We investigated structural and magnetic properties of CoMnSi (CMS) Heusler alloy films and giant magneto-resistance (GMR) ratio of current-perpendicular-to-plane (CPP) GMR sensor elements. The films were deposited with magnetron sputtering method and annealed at 673 K and 773 K. The CMS films were identified as B2 structure by using X-ray diffraction and the magnetization of the films were evaluated as 0.95 T. We fabricated the CPP-GMR sensors varying the composition of the CMS films, Co48 Mn21 Si31 (at. %) as Si-rich CMS and Co51Mn25Si24 (at. %) as CMS-ref, having a FeCo layer between the CMS and Cu spacer. It was found that the element with Si-rich CMS exhibited higher GMR ratio of 9.0% than that with CMS-ref. Our calculations indicate that larger spin polarization of contact region between the CMS film and the FeCo film relates to larger GMR ratio.

Following research in 2000 in which the benefits of using lateral creep to establish friction levels in the wheel/rail contact region were established, the author and his team pushed the operating regime to include the smaller, slower realm of hand-operated tribometry. Implementing and managing of both flange lubrication, and top of rail friction modification programs have become more widely adopted and hence there is a growing need for measurements that assist in quantifying the effectiveness of these programs. Likewise, the need to measure the success of these programs has become paramount. The current design, hand-push tribometer widely used throughout the world has limitations previously outlined and operators have pressed for improvements both in operating convenience and, in particular, in controlling the operating regime that defines the values produced. The key element is in maintaining a low creep or percent slip condition that any particular measurement is associated with. The original tribometer and its predecessors were not capable of controlling creep in the few percent range. A related limitation in previous designs was the tendency to have the measuring wheel momentarily stop, thereby leaving one spot on the wheel susceptible to rapid changes to its local condition. In the new design, for each increment of forward motion, the measurement wheel always rolls to a new position of both the measurement wheel and the rail.

A scanning method for determining the rheological characteristics of two-phase liquids and the corresponding experimental technique are considered. The structure of mechanical resistance of the water-oil contact region and its relation to the interphase tension have been shown.

This paper presents a two-dimensional contact stress analysis to investigate the effects of multiple inclusions on the contact pressure and subsurface stresses in an elastic half-plane. The boundary element method is used to analyze the contact problem where a set of integral equations is derived on the contact region and the matrix–inclusion interfaces. As the contact region is unknown a priori, an iterative procedure is implemented to determine the actual contact region and the contact pressure, and the tractions and displacements on the matrix–inclusion interfaces are obtained by solving the integral equations numerically. Numerical results show that the inclusions near contact surface could cause significant alterations in the contact pressure distribution. The stiff inclusions could toughen the surrounding material and reduce the internal stresses while the soft inclusions could increase the subsurface stresses.

Particle bridging between a water drop and a flat oil-water interface has been observed when the drop is brought into contact with the interface, leading to the formation of a dense particle monolayer of disc shape (namely, particle disc) that prevents the drop from coalescing into the bulk water phase. Unlike previous observations where particles from opposite interfaces appear to register with each other before bridging, the present experiment demonstrates that the particle registry is not a necessity for bridging. In many cases, the particles from one of the interfaces were repelled away from the contact region, leaving behind the particles from the other interface to bridge the two interfaces. This is confirmed by particle bridging experiments between two interfaces covered with different sized particles, and between a particle-covered interface and a clean interface. The dynamics associated with the growth of the particle disc due to particle bridging follows a power law relationship between the radius of the disc and time: r proportional, variant t0.32+/-0.03. A scaling analysis assuming capillary attraction as the driving force and a hydrodynamic resistance leads to the power law r proportional, variant t1/3, in good agreement with the experiment. In addition, we found that binary mixtures of two different sized particles can undergo phase segregation driven by the particle bridging process.

The performance of electronic and optoelectronic devices based on two-dimensional layered crystals, including graphene, semiconductors of the transition metal dichalcogenide family such as molybdenum disulphide (MoS2) and tungsten diselenide (WSe2), as well as other emerging two-dimensional semiconductors such as atomically thin black phosphorus, is significantly affected by the electrical contacts that connect these materials with external circuitry. Here, we present a comprehensive treatment of the physics of such interfaces at the contact region and discuss recent progress towards realizing optimal contacts for two-dimensional materials. We also discuss the requirements that must be fulfilled to realize efficient spin injection in transition metal dichalcogenides. © 2015 Macmillan Publishers Limited. All rights reserved.

The analytical solution for the plane contact between nonconforming C1 profiles with a curvature discontinuity is obtained and discussed. The initial gap between the undeformed profiles was represented by a double parabolic function having the curvature discontinuity within the contact region. On the basis of the analytical solution, the complete analysis of pressure distribution was obtained. A raw technique to find an approximate solution is presented and comparison to the analytic one provided. For the limit case of strong curvature ratio the asymptotic treatment is discussed in terms of consistency with hypotheses claimed.

The most expedient method of applying metallic coatings is friction plating with the use of rotating wire brushes (RWB). The coating metal is pressed against the bristles of the RWB and heated to high temperatures in the contact region. Particles of the coating metal are then captured by the ends of the bristles and transferred to the surface of the product being coated. The surface layer is simultaneously subjected to plastic deformation. The article presents the main parameters of the process and describes its ranges of application.

This study investigated the complete history of residual stress evolution in a stress-free titanium alloy, Ti–6Al–4 V under fretting fatigue loading condition. Compressive residual stress developed in the contact region due to the local plastic deformation between contacting bodies. The compressive residual stress then increased initially with increasing number of fretting fatigue cycles reaching to a maximum value, and then it decreased (or relaxed) with further cycling. This relaxation of compressive residual stress was due to the delamination and detachment of flake-like (wear sheet) material in the fretted region.

An axisymmetric contact problem of thermoelasticity for rotating bodies is analyzed with regard for heat generation in the contact region and convective heat exchange between the bodies and the ambient medium. The distribution of stresses in the bodies is determined. Special attention is given to the maximum tangential stresses and the possibility of appearance of tensile stresses.

The present work was undertaken to investigate the effect of sliding condition and wear surface state on the dry sliding wear behaviour of SiCp/Cu composite. Three kinds of sliding conditions, namely continuous sliding, interrupted sliding, and interrupted and cleaning sliding were employed. It was observed that a compact mechanically mixed layer (MML) was present on the worn surface of the composite, which effectively decreased the wear loss of the sliding pair. The new running in period of the interrupted tests led to breakage of the MML. Sufficient sliding and entrapment of wear debris in the contact region were two important preconditions for the formation of an MML. Therefore, continuous sliding or long period sliding is favoured to extend the life of this dry tribosystem.

When two liquid drops come into contact, they coalesce rapidly, owing to the large curvature and unbalanced surface-tension forces in the neck region. We use an ultra-high-speed video camera to study the coalescence of a pendent and a sessile drop, over a range of drop sizes and liquid viscosities. For low viscosity, the outward motion of the liquid contact region is successfully described by a dynamic capillary-inertial model based on the local vertical spacing between the two drop surfaces. This model applies even when the drops are of different sizes. Increasing viscosity slows down the coalescence when the Reynolds number m. For the largest viscosities, the neck region initially grows in size at a constant velocity. The neck curvature also becomes progressively sharper with increasing viscosity. The results are compared to previously predicted power laws, finding slight, but significant deviations from the predicted exponents. These deviations are most probably caused by the finite initial contact radius.

The problem of a thermoelastic interaction of two cylinders with separation of their contact surfaces due to local loading of lateral surfaces is formulated and solved. The effect of the multiply connected contact region is shown to exist under a certain relation between the linear thermal expansion coefficients of the bodies.

The influence of load on the wear and abrasiveness of hard boron carbide (nominally B4C) thin films is studied. We analyze the wear and abrasiveness data obtained from pin-on-disk tests in which the disks are coated and the counterparts (sliders) are steel balls. It is assumed that the dominant mechanism for slider wear by these nominally smooth coatings is mechanical abrasion of the slider by nano-scale asperities having relatively large attack angles, i.e. by sharp asperities. We propose a model in which we assume that (1) the abrasiveness of a contact is proportional to the number of asperities in the contact; (2) the areal contact density is uniform; and (3) the effect of increasing the load is to enlarge the initial apparent contact region between the ball and the disk. Using this model, the observed dependence of the wear rate on load follows relationships that are similar to Hertzian relationships.

We study stresses formed in two rigidly connected elastic half spaces made of different materials in the case where their interface contains a circular crack. The contact of the crack surfaces along the crack contour is taken into account and the solution of the integral equation of the problem is obtained by the Wiener–Hopf method in the closed form. The size of the zone of contact of the crack surfaces and the distributions of stresses in the contact region and on the interface of the half spaces outside the crack are found explicitly.

Silicon carbide (SiC) based devices perform very well in severe environments and show excellent device characteristics at very high temperatures and in high radiation environments. An analytical model for a lateral MOSFET that includes the effects of temperature variation in 6H–SiC poly-type has been developed. The effects of elevated ambient and substrate temperatures (300–600 K) on the electrical characteristics as well as the variation of large and small signal parameters of the lateral MOSFET have been studied. The model includes the effects of temperature on the threshold voltage, carrier mobility, the body leakage current, and the drain and source contact region resistances. The MOSFET output characteristics and parameter values have been compared with previously measured experimental data. A good agreement between the analytical model and the experimental data has been observed.

The plasma formations that appear in the contact region between two negative glow discharges have been studied by means of electrical and spectral methods. The experimental and theoretical research of the plasma formations show that the double layer is the final stage of a more complex plasma structure which is formed first.

Researches on wear and fatigue in rolling contact from a tribological viewpoint are introduced. Transmission of traction and accompanying microslip in the contact region play critical roles in these phenomena. First, a quantitative analysis of wear in rolling contact with microslip is introduced, and it is shown that a simplified microslip theory can explain its behavior. Second, a marked change in contact fatigue life with traction is demonstrated, and a theory is introduced which relates the fatigue life with cumulative shear strain in the subsurface.

The contribution of adsorption in a contact zone to adhesion between two nonporous bodies is discussed in the framework of the theory of adsorption in micropores. A contact region is presented as a...

This article is devoted to the experimental study of the ohmic contacts based on Ti/Al/Ni/Au metallization to the n+-doped region of the AlGaN / GaN heterostructure. Formed phases are studied at different temperatures. Based on the thermodynamic analysis of possible intermetallic reactions in the contact region, the optimum temperature range was found for the formation of ohmic contacts with a low contact resistance. The optimality of the modeled range is experimentally confirmed.

Multiwall carbon nanotubes (MWNTs) were manipulated in a transmission electron microscope, and the joining of two capped MWNT tips was performed by applying an electric current to the tips. The inosculation process was observed in situ while simultaneous current and bias voltage measurements were performed. Under application of a current of 95.9 μA across the contact region between the two MWNT tips, the formation of a tubular structure occurred only at the outermost wall layers of the MWNTs. At a higher current of 126.9 μA, the tubular structure collapsed without forming bonds between the inner wall layers of the two MWNTs. These results suggest that it is difficult to join the inner wall layers at the tips of MWNTs by only the control of the electric current.

A technique of pendant drop melt extraction (PDME) is reported and certain results describing thin stainless steel fibers obtained by means of PDME were studied. Adhesion interaction between metal melt and disc-crystallizer was also considered. The adhesion work was established to be approximately 1–2 J/m2. It was shown that melt adhesion to the disc-crystallizer is determined both by physical interaction and chemical processes in contact region.

The problem of a punch shaped like an elliptic paraboloid pressed into an elastic plate is studied under the assumption that the contact region is small. The action of the punch on the plate is modeled by point forces and moments. The method of joined asymptotic expansions is used to formulate the problem of one–sided contact for the internal asymptotic representation; the problem is solved with the use of the results obtained by L. A. Galin. The coordinates of the center of the elliptic contact region, its dimensions, and the angle of rotation are determined. The moments which ensure translational indentation of the punch are calculated and an equation that relates displacements of the punch to the force acting on it is given.

We show that, in a nanometric size stable electrodeposited Ni contact, it is possible to modify the magnetoresistance by applying current pulses and external magnetic fields whereby the same current path is used for detection and modification. We can pass from positive to negative magnetoresistance with values as large as 25% at room temperature, all in the same contact. We propose that the effect may be due to switching and moving domain walls in the contact region under the combination of current effects and external fields.

We use mid-infrared (MIR) spectroscopy to investigate the contact region at the Nb/InAs superconductor/semiconductor interface. We observe a remnant of the intersubband (ISB) resonance in Nb-clad InAs quantum wells, both in samples where we have grown Nb directly on InAs in situ, and samples where we have etch exposed the InAs surface before depositing the Nb. The presence of this remnant ISB indicates partial confinement of the electrons to the InAs. The similar resonance widths in the MBE grown Nb/InAs sample and the samples with Nb on etched InAs suggest that coupling of electron states in the InAs to those in Nb, rather than etch-induced damage, produces most of the resonance broadening.

The theory of normal contact of rigid bodies with allowance for Coulomb friction is developed. The Boussinesq principle is generalized to contact problems with friction.

Plane steady contact problems of a rigid insulated cylinder sliding over a thermoelastic layer is solved. The heat generation in the contact region is caused by friction forces. The problem is investigated by the method of integral equations. An exponential series approximation is used for the evaluation of the kernels of integral equations. Numerical results are presented in diagrams.

Recent studies show that pseudo-elastic TiNi alloy exhibits high resistance to wear, compared to many conventional wear-resistant materials. It is demonstrated that hardness is not crucial to the wear resistance of this alloy, since its hardness is lower than those of conventional wear-resistant materials. In order to understand the excellent wear behaviour of TiNi alloy and determine the factors responsible for wear resistance of the alloy, the performance of Ti–50.3 at.% Ni alloy during a dry sliding wear process was investigated and compared to a 2Cr13 steel. It was demonstrated that the TiNi alloy performed much better than the 2Cr13 steel, although the latter has a higher hardness. It is expected that the high wear resistance of TiNi alloy is attributable to its special mechanical behaviour, in particular its so-called pseudo-elasticity, caused by reversible martensitic transformation. Mechanical and thermal properties of Ti–50.3 at.% Ni alloy were studied and a FEM analysis was made to investigate the plastic strain in the contact region and to correlate the wear behaviour of TiNi alloy to its pseudo-elastic and thermal properties that are influenced by the martensitic transformation.

Part 1 of this paper\[1] reviewed the modeling approaches and correlations used to study the interface heat transfer phenomena of the roll-strip contact region in rolling processes. The thermal contact conductance approach was recommended for modeling the interface phenomena. To illustrate, the recommended approach and selected correlations are adopted in the present study for modeling of the roll-strip interface region. The specific values of the parameters used to correlate the corresponding thermal contact conductance for the typical cold and hot rolling of steels are first estimated. The influence of thermal contact resistance on the temperature distributions of the roll and strip is then studied. Comparing the present simulation results with previously published experimental and analytical results shows that the thermal contact conductance approach and numerical models used can reliably simulate the heat transfer behavior of the rolling process.

In this paper, a two-dimensional contact problem of two dissimilar anisotropic elastic bodies is studied. The shapes of the boundaries of these two elastic bodies have been assumed to be approximately straight, but the contact region is not necessary to be small and the contact surface can be nonsmooth. Base upon these assumptions, three different boundary conditions are considered and solved. They are: the contact in the presence of friction, the contact in the absence of friction, and the contact in complete adhesion. By applying the Stroh’s formalism for anisotropic elasticity and the method of analytical continuation for complex function manipulation, general solutions satisfying these different boundary conditions are obtained in analytical forms. When one of the elastic bodies is rigid and the boundary shape of the other elastic body is considered to be fiat, the reduced solutions can be proved to be identical to those presented in the literature for the problems of rigid punches indenting into (or sliding along) the anisotropic elastic halfplane. For the purpose of illustration, examples are also given when the shapes of the boundaries of the elastic bodies are approximated by the parabolic curves.

Transparency of the tribological process by sensory and audio-visual process recording. By multi-media recording of the friction event the elementary contact processes get transparent so that damage causes can be recognized. For this additional to the usual tribological readings audio-visual information were time synchronously gathered. By use of thin integrated sensors temperature or pressure is measured continuously with high local resolution during the friction process inside the contact region. The damage mechanisms are analysed systematically and make influence measures possible to coating optimization to exclude an early failure of a tribological system.

A solution is obtained for a contact problem concerning the tension of a rectangular elastic plate with a circular hole into which a rigid stationary pin has been inserted. There is a small gap between the hole and the pin, which is of circular cross section. Friction acts in the contact region in accordance with the Coulomb law. The finite-element method and the Boussinesq principle are used to determine the load that realizes a specified contact region. Two variants of boundary conditions on the contour of the hole are examined.