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We propose a cyclic flattened Brazilian disc (FBD) testing method to measure the tensile fatigue properties of brittle rocks. Our method has obvious merits in its specimen preparation and experimental operation. Two parallel flattens are introduced in the disc specimen, which facilitate easily and uniformly loading the specimen without special loading devices required. Moreover, the contact regions between two flattens and loading planes barely change during the entire loading and unloading process, ensuring a consistent contact condition. With certain appropriate loading angles, this method guarantees that the very first breakage of the specimen occurs at the center of the disc, which is the prerequisite of the Brazilian-type indirect tensile tests. To demonstrate our new method, nine cyclic FBD tensile tests are conducted. The fatigue load-deformation characteristics of FBD specimens are revealed. The tensile fatigue lives of tested specimens are observed to increase with the increase in cyclic loading frequency. Our proposed method provides a convenient and reliable approach to indirectly measure the fatigue tensile properties of brittle rocks and other brittle solids subjected to cyclic tensile loadings.

The self-healing property of a hydrogel applied to a glass substrate as a thin polymer coating was assessed. The motivation was to develop a durable hydrogel coating that may be used to protect the surface of precision components from surface damage and scratches. The intrinsic swelling behavior of hydrogel fibers when they are exposed to moisture was exploited to attain the self-healing effect. The mechanical and self-healing properties of the dehydrated hydrogel coating by the freeze-drying process and the hydrated hydrogel coating that was reconstituted by the addition of water were analyzed. After conducting sliding tests with different loads and sliding distances, the wear area was hydrated with water to successfully induce self-healing of the hydrogel coating. It was also found that both the dehydrated hydrogel coating and the hydrated hydrogel coating had improved friction characteristics. In particular, the hydrated hydrogel coating had a much higher durability than the dehydrated coating.

Blades with a friction damper have been used in a steam turbine and a gas turbine to improve the blade reliability. In particular, for a gas turbine blade of the upstream stage, under-platform dampers have been widely used, where the damper pieces with various geometries are inserted into the platforms of the adjacent blades. The damper piece is designed so that its surface contacts the platform surface uniformly. However, the contact conditions of the damper piece (in other words, the equivalent stiffness and the damping caused by the damper piece) may change appreciably blade by blade because of the likes of manufacturing tolerance, blade deformation in operation, and wear of the damper piece. Therefore, it is essential to consider the mistuning effect caused by the variation of the contact condition of the damper piece in evaluating the vibration response of the bladed disk with the under-platform damper. In this study, a mistuned bladed disk with under-platform dampers is represented by the equivalent spring-mass model. Frequency response analysis and random response analysis are carried out using the direct method and Monte Carlo simulation. Carrying out an extensive parametric study, the effect of the variation of the contact condition caused by the damper piece on the vibration response of the bladed disk is clarified.

The goal of this paper is to study a quasistatic frictionless contact problem for a viscoelastic body in which the constitutive equation is modeled with the fractional Kelvin–Voigt law and the contact condition is described by the Clarke subdifferential of a nonconvex and nonsmooth functional. The variational formulation of this problem is provided in the form of a fractional hemivariational inequality. In order to solve this inequality, we apply the Rothe method and prove that the associated abstract Volterra inclusion has at least one solution.

Summarization: In this article, a multi-scale computational homogenization scheme is proposed for the study of composite materials. A classical unilateral contact law has been incorporated in the microscopic level, for the investigation of the contact between the constitutive materials. The either-or decision resulting from the contact-no contact condition in the microscopic scale, makes the problem non-linear. This change in the contact state of the microscopic level, is taken into account by the proposed approach. Debonding between the matrix and the surrounding fibers and its impact on the macroscopic structure, are depicted. In addition, a change in the direction of the macroscopic load during analysis, results in a non-linear behavior due to the alteration of the microscopic contact state. The distribution of the displacement jump is influenced in this case, as well. Παρουσιάστηκε στο: Computational Materials Science

In this paper, through the establishment of a finite element model of radial tire, the finite element analysis of radial tire is made under vertical load condition. The laws of deformation, stress and strain of different wear tire are obtained. At last, the analysis result is discussed.

The present study seeks to realize an improved understanding of the action of cutting fluid through direct observation of the chip-tool interface. That is, using transparent tools made of sapphire in conjunction with a high-speed, CCD-based imaging system, the chip-tool contact condition and its evolution in the presence of cutting fluid are directly observed during 2-D orthogonal machining of pure lead and Al6061-T6. Then, spatial and temporal analysis of the images of the chip-tool interface is made for measuring the contact length and velocity profile along the tool rake face, and the contact conditions are correlated with the cutting forces measured. The results are compared with those made when cutting dry to clarify the effects of cutting fluid action, and a picture of the action of cutting fluid at the chip-tool interface is presented finally.

Intergroup disgust sensitivity (ITG-DS) reflects an affect-laden revulsion toward out-groups. Previous attempts to weaken its prediction of prejudice have failed. Given that clinical approaches to disgust sensitivity successfully utilize mental imagery, we consider contact simulation interventions. Participants were randomly assigned to control, standard imagined contact, or an elaborated contact condition (elaborated imagined contact [EIC]; detailed imagination involving physical contact with a homeless person, with relaxation instructions). Both contact conditions (vs. control) significantly weakened the link between ITG-DS and prejudice, yet only EIC weakened the relation between ITG-DS and out-group trust. Mediated moderation analysis confirmed that EIC significantly attenuated the link between ITG-DS and prejudice through increasing trust. Clinically relevant treatments are thus valuable in severing the association between (a) ITG-DS and (b) lower out-group trust and greater out-group prejudice.

The oil lip seal operation is affected by the kinematics of the relative motion of the lip surface with respect to the shaft during both assembly and operation. Moreover, the variable position of the contact area along the sealing edge determines the contact pressure distribution and hence the wear rate of the lip.

Although numerous FE models have been proposed to analyze the mechanical behavior of simple strands, they seldom examine the contact condition and lateral loading behavior that may influence local stress distribution and lifetime performance. In this study, serial 3D FE models of a seven-wire strand were developed to discover the interface mechanism under longitudinal and lateral loading. A partially restrained model was proposed and carefully studied. Friction minimally influenced longitudinal stiffness and had a limited effect on lateral behavior. FEM analysis predicted uneven stress distribution under lateral loading simulation. Both strand bending phase and wire bending phase were observed near the termination. Microslip and contact line migration mainly occurred between helical wires.

This study presents the mechanical behavior of a ventilating window (a tsunami damper) on the building wall of a nuclear power plant. The window, which is under development, is used to ventilate a machinery room and the building under normal conditions, but it also provides a safety barrier for critical equipment against a tsunami caused by an earthquake. A finite element analysis was conducted to investigate the deflection and the stress distribution of the window under given loading conditions. With symmetry, a one-quarter portion of one window was modeled, and the pressure due to a great tide is assumed to be 7 bar. A structural analysis of the assembled frame, composed of a blade and casing, was also conducted using contact conditions to find the stress and strain configurations caused by the applied pressure. Key Words : Tsunami Damper(쓰나미 댐퍼), Mechanical Behavior(기계적 거동), Finite Element Method(유한요소법), Contact Condition(접촉조건), Watertightness(수밀성) * Department of Mechanical Design Engineering, Graduate School, Pukyong National University # Corresponding author : Department of Mechanical & Automotive Engineering, Pukyong National University E-mail : btkim@pknu.ac.kr** Jibtech Co. Ltd

This paper evaluates the effects of yawing misalignment contact on the tooth root bending stress values of spur gear pair during the gear meshing cycle. A model basedon involute 3DparametricCAD geometry, of spur gear design ISO 6336:2006 is analyzed with worst loading position when yawing misalignment (Y) exist due to assembly error (AE) between 0.20 to 0.40 in degree scale values. Finite-element method (FEM) with dynamics module from ANSYS is used in order to calculate the tooth root bending stress (TRBS) at the critical region with respect to face width of pinion and gear section. A comparison is made between standard high point single tooth contactmodels (HPSTC) to this model as verification. Further analysis showeda good agreement that these methodologies are adequate in order to conduct a real time dynamics simulation to define the value of TRBS in Y condition due to AE. Yawingmisalignment influence factor (YMIF) was introduced as an indication of TRBS values in consideration of Y due to AEshows a higher result for pinion, give a good justification that the pinion is weaker compared to the gear in Y condition.

Constrained groove pressing (CGP) is a newly developed severe plastic deformation technique for producing ultra-fine grained sheet metals. In this study, the effects of friction on tensile properties, microstructure and strain distribution of commercially pure Al sheets were investigated using experimental and numerical methods. Results show that the improvement of contact condition between the dies and sheet suspends the occurrence of micro-cracks and induces more CGP passes. A finer and more homogeneous microstructure is obtained after 6 passes with Teflon layers as lubricant. The ductility of CGP sheets experiences apparent enhancement while the strength gradually decreases. In addition, the uniformity of strain distribution falls with the increase of friction coefficient.

In this work, a numerical approximation by the finite element method of a quasi-static, frictionless, unilateral contact problem between two thermoelastic bodies, in two dimensions, is considered. The approximation scheme is based on a penalty formulation used to replace the Signorini contact condition. Convergence results and error bounds are obtained and some numerical experiments presented.

Dupin cyclides form a 9-dimensional set of surfaces which are, from the viewpoint of differential geometry, the simplest after planes and spheres. We prove here that, given three oriented contact conditions, there is in general no Dupin cyclide satisfying them, but if the contact conditions belong to a codimension one subset, then there is a one-parameter family of solutions.

Background and objectives Fear of contamination can be evoked following physical contact with a dirty, harmful or polluted item, person, or place (contact contamination) or in the absence of physical contact with a contaminant (mental contamination). The spread of contact contamination does not degrade over successive degrees of removal from the contaminated source. However, to date, the spread of mental contamination has not been empirically investigated. This study aimed to examine the spread and degradation of mental contamination. Methods The paradigm of Tolin et al. (2004) was adapted. Feelings of mental contamination were evoked, and participants were asked to transfer these feelings to an uncontaminated pencil by touching it (contact condition) and without touching it (no contact condition). Results Seventy-two percent of participants in the contact condition and 48% participants in the no-contact condition reported being able to transfer contamination to a clean pencil, demonstrating that mental contamination transfers both with and without contact. In both conditions, the mental contamination subsequently spread to a series of 12 neutral pencils without degradation. Conclusions These findings suggest that mental contamination can be transmitted and spread in the absence of physical contact, similar to contact contamination.

Rolling contact fatigue and wear of rails are inevitable problems for railway system due to wheel and rail contact. Increased rail wear and increased fatigue damage such as shelling, head check, etc. require more frequent rail exchanges and more maintenance cost. The fatigue crack growth and wear forming on the contact surface are affected by a variety of parameters, such as vertical and traction load, friction coefficient on the surface. Also, wear and crack growth are not independent, but interact on each other. Surface cracks are removed by wear, which can be beneficial for rail, however too much wear shortens the life of rail. Therfore, it is important to understand contact fatigue and wear mechanism in rail steels according to a variety of parameters. In this study, we have investigated fatigue and wear characteriscs of rail steel using twin disc testing. Also the comparative wear behavior of KS60 and UIC 60 rail steel under dry rolling-sliding contact was performed.

A method for predicting and analyzing the tooth contact pattern, vibration, and strength of a generated hypoid gear is needed to achieve a low-noise design and adequate quality control. However, it is not easy to analyze the performance of a generated hypoid gear because the tooth flank form is complicated and has a significant influence on the overall performance. In order to solve this problem, in this research, a method for analyzing one of the gear dynamics excitations and contact condition of a generated hypoid gear that considers the measured tooth flank form is proposed. The contact pattern and transmission error are measured experimentally and are compared with the analysis results. It is confirmed that the result from the proposed analysis method agrees with the experimental result.

Fretting is a phenomenon occurring between two surfaces having relative oscillatory motion of small amplitude. Fretting damage occurs on the surfaces of contacting components. An accurate assessment of critical fretting variables such as contact traction, contact condition (stick & slip) and contact stresses over the blade-disc attachment is essential to characterize the fretting performance and to assess the reliability of rotor. Such an understanding helps in the design of lighter engines, with better performance and improved safety. Rotor consists of a number of contact pairs of disc and blade, it would be complex to study all the interfaces together. Hence a simplified approach of studying a single lobe of a dovetail interface for a sector is considered to understand the fretting behavior of fan and compressor blade-disc interface. This paper examines to investigate the acute variations in stress along the Flank length, thickness, for varying friction and rotational speed of the disc/blade interface.

The purpose of this work is to construct a tribo-fatigue damage map of high-speed railway wheel material under different tangential forces and contact pressure conditions through JD-1 testing equipment. The results indicate that the wear rate of the wheel material varies with tangential force and contact pressure. The wear mapping of the wheel material is constructed and divided into three regions: slight wear, severe wear, and destructive wear, based on the wear rate under each test condition. With an increase in tangential force and contact pressure, the maximum crack length and average crack length of the wheel material increases. According to the surface damage morphologies and corresponding statistical results of average crack length of wheel material under each experiment condition, a tribo-fatigue damage map is constructed and divided into three regions: slight fatigue damage region, fatigue damage region, and severe fatigue damage region. Fatigue cracks initiate on the wheel specimen surface. Some cracks may propagate into material and fracture under cyclic rolling contact, some cracks may grow into inner material with a certain depth, and then turn toward the surface to form material flaking, some cracks may always propagate parallel to the wheel roller surface.

A three-dimensional (3D) finite element model that includes the microstructure of grains and grain boundaries is developed for studying the rolling contact fatigue (RCF) damage caused by a rolling steel wheel on a steel railway. The 3D model uses a crystal plasticity-based micromechanical framework for simulation of stress-strain behavior inside the grains, and cohesive elements with traction-separation law for modeling the intergranular fatigue damages. A combination of moving normal Hertzian load and tangential loads are employed to mimic the rolling contact conditions. The effect of various parameters such as friction coefficient, traction, partial slip contact and wheel load on RCF is studied. The results reveal that RCF cracks initiate slightly below the surface for large wheel loads and low tractions. The cracks migrate toward the surface as the wheel-rail traction increases. For high tractions, the cracks initiate at the rolling surface. Under partial slip contact condition, there is a large change in rail life for small normalized tractions. With a slight increase in the latter, the rail life significantly decreases. For moderate to large tractions, rail life remains relatively unchanged or slightly increases. The results of the study appear to agree with anecdotal observations by the U.S. railroads from revenue service operation.

The turn-to-turn contact resistance (characteristic resistance) is a very important factor to a no-insulation (NI) (RE)Ba $_2$ Cu $_3O_y$ (REBCO) pancake coil. It characterizes the stability and charging delay of NI REBCO pancake coils. However, the ordinary sudden-discharging method cannot measure the turn-to-turn contact resistance under different conditions, such as an operating current, a temperature, and an external magnetic field. Although the turn-to-turn contact condition is strongly affected by the pressure inside of the NI REBCO coils, the feature of the contact resistance must be clarified to estimate the stability of NI REBCO coils. In this paper, we have proposed a new method to measure the turn-to-turn contact resistance applying ac current. The theory and the measurement results are also shown. The measured turn-to-turn contact resistance is reasonable, compared with that measured by the ordinary sudden-discharging method. In near future, we will measure the turn-to-turn contact resistance under different conditions by means of the proposed method.

Exact sum rules involving the contact values of the density profiles and bulk osmotic pressure in spherical and cylindrical electric double layers are formulated. When the radius of curvature in these systems tends to infinity, the contact conditions reduce to the well-known contact condition in planar double layer due to Henderson, Blum, and Lebowitz (1979). However, unlike the latter relation, the contact conditions in the non-planar geometries are non-local, and require for their implementation full knowledge of the electrode–ion singlet distribution functions.

In elastic contact problems it is usually required that the contact force has to be directed normally to the contact surface in the absence of friction. For an obstacle with nonsmooth surface this gives infinitely many normal directions at an edge or at a corner. For the case where a nonlinearly elastic rod under terminal loads is hanging over a needle, it is shown that the balance equations supplemented with such a normality condition have a continuum of solutions. Moreover, an additional contact condition is derived from a corresponding variational problem by means of special inner variations that preserve the shape of the rod. This way one is finally lead to a unique solution at least locally.

Skin-pass rolling (or temper rolling) is the final forming step in the production of cold rolled steel sheets. Although a large roll radius compared to the contact length is one of the characteristics of skin-pass rolling conditions, numerous studies have been conducted thus far using laboratory mills with small radius rolls. In this paper, the influence of roll radius on the contact condition and material deformation in skin-pass rolling is examined and clarified by numerical analysis by an elastic–plastic FEM analysis as well as experimental rolling tests, which were performed to verify the result of the analysis. Some characteristics of skin-pass rolling related to pressure distribution, contact condition and material deformation are not properly simulated using small radius rolls. Considering characteristic skin-pass rolling conditions, two cases using simplified models, i.e., vertical compression and rolling with a circular, rigid roll, were analyzed.

Based on Abaqus/explicit dynamics finite element program, an ax symmetrical numerical model, the infinite fringe condition and friction contact condition were built, and then the surface contact stress condition of the dynamic consolidation was studied. The time-load properties of dynamic consolidation, the spread law of contact pressure for rammer bottom and the friction influence to contact stress between the hammer and foundation were gained. The results indicate that the dynamic consolidation load can be simplified to triangular load with the weight of the hammer itself; the contact stress distribution between the hammer and the foundation is not uniform; and frictionless contact hypothesis can led errors to the simulated result.

For the calculation of micro contact parameters of rough surfaces, there are some models available by which one can calculate the micro contact pressure and area. Some of them require large computers and long computing time. Still, all these models represent just one specific contact condition. In order to gain results, fast statistical micro-contact models can be used, if the contact conditions allow for it. In this study the outcome of boundary lubricated multidirectional pin-on-ball wear tests of polished and textured metal surfaces is analyzed by means of micro contact parameters according to the Greenwood–Williamson model. Thus, surface profiles are measured at different loading cycles during run-in and steady state up to 500,000 cycles. These profiles are evaluated statistically as to the main parameters, e.g. the zeroth, second, and fourth spectral moments representing the variance of the heights, slope, and curvature of the asperities. These and the plasticity index are discussed with respect to their possible relationship to wear behavior.

Background: Extreme fear of contamination within Obsessive Compulsive Disorder is traditionally conceptualised as a physical phenomenon. More recent research has supported the notion of ‘mental’ contamination, in which people feel contaminated in the absence of physical contact. The current research sought to determine whether feelings of contact and mental contamination could be induced within a non-clinical sample, whether the impact of mental and contact contamination was comparable in terms of associated feelings and behaviour and whether related psychopathology related to the impact of the tasks. Methods: Undergraduate students (n=60) completed OCD relevant measures and were randomly assigned to either a contact contamination condition (CC: moving a bucket of fake vomit) or a mental contamination condition (MC: thinking about a bucket of vomit). Results: Both manipulations induced feelings of contamination. Participants in the contact condition had significantly greater urges to wash than those in the mental condition. Neutralising behaviour did not differ across conditions. Conclusions: Feelings of contamination can be induced in the absence of physical contact and for those in the MC group, some aspects of OCD-relevant psychopathology were related to the impact of the manipulation. These findings have implications for the understanding and treatment of contamination-related fears in OCD.

The tribological conditions at the contact between the cutting tool and the chip are of great importance when analyzing the machining process. By knowing the contact conditions on the rake face of the cutting tool the wear on the clearance and rake face may be predicted in terms of size and type of wear. A certain value of the surface stresses is often thought of as leading to a higher wear rate of the cutting tool and thus a shorter tool life. In this article two different methods for experimentally measuring the contact condition on the clearance and rake face of the cutting tool are presented and illustrated with results obtained while turning AISI 4140. Results are also obtained in terms of how the surface roughness value of the cutting tool influences the contact condition. It was found that the tool surface topography may have a significant impact on the tribological performance during machining.

In tube forming, differences in deformation characteristics between thin- and thick-walled tubes must exist. Experimental results using metal tubing with an outer diameter (D) of 8 mm are discussed in this study. Cross-shaped tube hydroforming of 0.5-mm- and 0.8-mm-thick specimens was examined. Protruded long branches were formed under a range of constant fluid pressures and relatively large axial feeding, approximately 4D. The 0.8-mm-thick specimens had a wider range of faultless forming conditions than the 0.5-mm-thick specimens. There seemed to be a boundary in thickness between 0.8 mm (0.10D) and 0.5 mm (0.06D). In addition, the contact condition between the tubular specimen and die strongly affected forming results. An MoS2 spray and PTFE sheets were used as lubricants to examine the effects of friction on axial feeding force and tube deformation. The highest axial feeding force was recorded under the forming condition of 0.8-mm-thick tubing and an MoS2 spray without PTFE sheets. The magnitude of forming pressure had a marginal effect on feeding force. The formed length of branches depended on forming pressure and lubrication.

This paper presents the development of a multiple model estimation approach for the identification of the adhesion limit to overcome the problem of the wheel slip/slide at the rail wheel-rail contact. The contact characteristics at the rail wheel-rail interface are both highly nonlinear and subject to changes due to exposure to external contaminations. The detection of adhesion and its changes is therefore scientifically challenging, but would provide a critical information in the control of trains to avoid undesirable wear of the wheels/track but also the safety compromise of rail operations. This study exploits the variations in the dynamic behaviour of the railway wheelset caused by the contact condition changes and applies a bank of Kalman filters designed at selected operation points for the adhesion estimation. A fuzzy logic system is then developed to identify the contact conditions by examining the residuals from the Kalman filters.

Since the number of trans-femoral amputees has been increased by industrial or traffic accidents in modern society, a prosthetic limb as typified by trans-femoral prosthesis has been required. On the other hand, the sprinting motion of unilateral trans-femoral amputee sprinters has been investigated to determine a direction for training with high level at maximal velocity. However, structural optimization of the prosthetic foot for the jumping movements continued from sprinting motion based on experimental evidence consistent with biomechanics has not been investigated yet. In this paper, we aim to optimize the structure of the prosthetic foot for the jumping movements of a trans-femoral amputee considering ground reaction forces based on biomechanical evidence as each contact condition to the floor. As a result of applying proposed multiple objective optimization technique using response surface method and desirability function to the prosthetic foot by finite element analysis, we obtained optimum design variables. Finally, we improved the structure of the prosthetic foot by obtaining sufficient larger deflections and optimum design variables based on the evaluation of the simulation results and showed the effectiveness of the structural optimization concerning the prosthetic foot.

This paper presents an elastic transmission model of spur gear (2-D) sets by means of combination with the kinematic geometry and elastic theory of gearing for analysis of transmission error (TE). Based on conventional contact condition between a teeth pair, an elastic contact mathematic equation is established, whose elastic deformation is caused by contact, bending and torsion of gears. The elastic contact equation involves time-varying center distance. For double tooth pairs contact, a compatibility equation is comprehensively established to implement continuously transformation. A spur gear (2-D) set is used as example to analyze the influences of the elastic deformation and center distance of the gears on the contact position and TE. The case study shows that the method of using mathematical model to study the gears TE presented in this paper is reliable. The work lays the theoretical foundation for further accuracy analysis and design.

Tyre-road contact condition information would benefit many vehicle safety and control systems. However, direct information is still not available in production vehicles. Tyre sensing could provide this necessary information but many aspects must still be studied. In this paper, a physical ring tyre model is used to estimate and remove the acceleration profile caused by the contact deformation from the measured in-tyre acceleration data. This residual acceleration can then be used to study the tyre-road contact conditions. A simple analysis with standard deviation is used to show the effects of different road surfaces on the measured in-tyre acceleration.

International audience; Time-variant muscle responses under electrical stimulation (ES) are often problematic for all the applications of neuroprosthetic muscle control. This situation limits the range of ES usage in relevant areas, mainly due to muscle fatigue and also to changes in stimulation electrode contact conditions, especially in transcutaneous ES. Surface electrodes are still the most widely used in noninvasive applications. Electrical field variations caused by changes in the stimulation contact condition markedly affect the resulting total muscle activation levels. Fatigue phenomena under functional electrical stimulation (FES) are also well known source of time-varying characteristics coming from muscle response under ES. Therefore, it is essential to monitor the actual muscle state and assess the expected muscle response by ES so as to improve the current ES system in favor of adaptive muscle-response-aware FES control. To deal with this issue, we have been studying a novel control technique using evoked electromyography (eEMG) signals to compensate for these muscle time-variances under ES for stable neuroprosthetic muscle control. In this perspective article, I overview the background of this topic and highlight important points to be aware of when using ES to induce the desired muscle activation regardless of the time-variance. I also demonstrate how to deal with the common critical problem of ES to move toward robust neuroprosthetic muscle control with the Evoked Electromyographically Controlled Electrical Stimulation paradigm.

International audience; In the current study, the dynamic mechanical behaviour of a masonry cupola composed of non-convex discrete elements is investigated. This cupola is designed in innovative and modern ways and was recently constructed with stone blocks in the south of France. The necessity of applying an accurate numerical modelling method being able to take into account the real geometry of each non-convex block is also presented and discussed. The stability state of this masonry structure, by considering the different levels of seismic loads is studied. In addition, the effects of changes in the contact condition between blocks, or the blocks and the structure foundation, are comprehensively investigated.

In a frequently quoted paragraph, Benardete presented the “paradox of the gods” in the following terms.

Based on analyzing the contact condition of the cutter and the work piece in orthogonal turn-milling machining, orthogonal cutting experiments were implemented with several machining parameters, and finally obtained conclusions about cutter wear and work piece roughness influenced by 3 factors. The biggest effect factor which affects the cutter wear is the cutter offset, the number of cutter teeth takes the second place, and the axial feed rate affects the least to cutter wear. This conclusion can be used to choose fit machining parameters in turn-milling machining.

This research focuses on the electric wheelchair controlled by Hu man Body Motion Interface (HBM I). HBM I uses the body motion which is caused by the voluntary movement. Fro m our previous research, it has been confirmed that HBMI, which uses the center of weight on the pressure sensor attached on the backrest, has the ability of an interface. However the problem has also remained. The velocities of each wheel have been determined in proportion to the difference between initial and present position of the center of weight. This difference is generated by the inclination of the body. In some cases, while user leans his/her upper body, the difference doesn't increase due to the contact condition between body and backrest. In this case, the user cannot control the wheelchair arb itrarily in spite of leaning his/her body. For this prob- lem, the gain which is proportion parameter between d ifference of center of weight and velocity of each wheel should be increased. However, too big gain lets the wheelchair cannot keep a stop. In order to solve this problem, first, we consider extracting user's stop intention by using self-organizing map (SOM). Second, we eliminate constant pressure data on the backrest when calculat ing the center of weight. By these operations, the wheelchair can keep a stop while the user wants to keep a stop, and the velocities of each wheel are generated even if the difference of center of weight is small.

This article employs an adaptive wear modeling method to study the wear progress in radial sliding bearings contacting with a rotary shaft. Mixed Lagrangian–Eulerian formulation has been used to simulate the contact condition between the bearing and the shaft, and the local wear evolution is modeled using the Archard equation. In the developed wear processor algorithm, not only remeshing is performed on the contact elements, but also is executed for their proximity elements. In this way the wear simulation becomes independent of the size of the contact elements. Validation was done for a laminated polymeric composite bearing. The composite has been modeled as a linear orthotropic material. The wear coefficients were obtained from flat-on-flat experiments and were applied as pressure and velocity dependent parameters in the wear processor. Finally, the effect of the clearance on the wear of the radial bearings has been studied numerically. The simulations also demonstrate how the contact pressure evolves during the wear process, and how the clearance influences this evolution.

Rabinowitz Floer homology has been investigated on submanifolds of contact type. The contact condition, however, is quite restrictive. For example, a product of contact hypersurfaces is rarely of contact type. In this article, we study Rabinowitz Floer homology for product manifolds which are not necessarily of contact type. We show for a class of product manifolds that there are infinitely many leafwise intersection points by proving the Kunneth formula for Rabinowitz Floer homology.