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Torque-controlled expansion anchors are widely used as anchoring elements in heavy nonstructural elements. Although the installed torque is not considered a design parameter for determination of anchor strength, it can affect the contact condition between the concrete and anchor as well as the failure mode under tensile load. This study performed pull-out experiments (total 85 specimens) for torque-controlled expansion anchors to evaluate the pull-out behavior under various installation conditions. Experimental results indicated that obtained inflection load and maximum displacement were affected by the installation torque. Concrete splitting failure was affected by pull-out behavior on concrete below critical edge distance. While maximum pull-out loads of M12 and M16 anchor was similar under the same embedment depth, pull-out behavior of the both types of anchors provide different characteristic. Accordingly, these results were analyzed to investigate the influence on anchor strength.

Serious wheel polygonal wear usually causes drastic wheel/rail interactions, which threats the running safety of railway vehicles. This paper presents an investigation into the effect of polygonal ...

Asphalt pavement is a multi-layer continuous structure with an interlayer bonding condition that can greatly influence its bearing capacity and must be monitored over the whole service length. Hence, proper maintenance and rehabilitation measures are taken and better feedback can be made for the design. Nevertheless, asphalt pavement interlayer bonding condition plays a hidden role and is difficult to quantify unless applying damage discovery techniques like drilling core process. The original structure is destroyed by the damage detection approaches, the results also suffer from low coverage rate and high dispersion, therefore, actual engineering demands are not satisfied. Here, some recent methods are briefly presented based on asphalt pavement interlayer bonding condition non-destructive diagnosis and their restrictions are discussed. Moreover, a new technique is provided with the merits of utilizing only mechanical simulation and overall superficial distresses condition evaluation index with high accuracy. This simulation procedure adopts bridging principles to build a connection between asphalt pavement superficial distresses and asphalt pavement micro mechanic parameters. It uses a structure behavior equation capable of identifying four typical deterioration modes and has specific physical meaning parameters to predict asphalt pavement overall superficial distresses. The established model allows the asphalt pavement interlayer bonding acting as a hypothetical input variable. The known input variables include easily obtainable design parameters of the asphalt pavement structure, historical superficial distresses, surface deflection, traffic load, and environmental factors, however, the output is the predicted asphalt pavement overall superficial distresses condition. The asphalt pavement interlayer bonding condition is defined by contrasting the theoretical asphalt pavement overall superficial distresses conditions between its complete bonding condition and discontinuous bonding condition to a certain degree. Examples in parts of the Jingha highway show that great discrepancies exist between theoretical asphalt pavement overall superficial distress in the condition of complete interlayer bonding and actual asphalt pavement overall superficial distress. The actual asphalt pavement sections in overall superficial conditions are deteriorated much faster than normal ones. By setting the asphalt pavement interlayer bonding continuations as 75% and 90% for K315–K316 section and K316–K317 section, respectively, the revised and predicted overall superficial distresses of the theoretical asphalt pavement are consistent with the real ones. The hypothetical values are then chosen as the diagnosed quantitative asphalt pavement interlayer bonding continuations and are proven to be correct through drilling core sample results. The analyses in other sections show that middle traffic volume asphalt pavement structure is quite weak when its interlayer bonding continuation is 70%, and under this value, its bearing capacity is almost equivalent to the situation when its interlayer bonding continuation is 0%; when its interlayer bonding continuation is 85% or more, its bearing capacity is almost equivalent to the situation where its interlayer bonding continuation is 100%. This proposed non-destructive diagnosis method for asphalt pavement interlayer bonding condition is effective and shows good application prospects in road engineering.

Fixed dentures (bridges) are often selected as a treatment option for a defective prosthesis. In this study, we assess the contact condition between the base of the pontic and oral mucosa, and examine the effect of prosthetic preparation and material biocompatibility. The molars were removed and replaced with experimental implants with a free-end type bridge superstructure after one week. In Experiment 1, we assessed different types of prosthetic pre-treatment: (1) the untreated control group (Con: mucosa recovering from the tooth extraction), (2) the laser irradiation group (Las: mucosa recovering after the damage caused by a CO2 laser), and (3) the tooth extraction group (Ext: mucosa recovering immediately after the teeth extraction). In Experiment 2, five materials (titanium, zirconia, porcelain, gold-platinum alloy, and self-curing resin) were placed at the base of the bridge pontic. Four weeks after the placement of the bridge, the mucosa adjacent to the pontic base was histologically analyzed. In Experiment 1, the Con and Las groups exhibited no formation of an epithelial sealing structure on the pontic base. In the Ext group, adherent epithelium was observed. In Experiment 2, the sealing properties at the pontic interface were superior for titanium and the zirconia compared with those made of porcelain or gold-platinum alloy. In the resin group, a clear delay in epithelial healing was observed.

Clinically, the stable sole‐ground contact in the diet is considered as important for achieving safe swallows in the dysphagic patients. However, the effects of varied sole‐ground contacts on swallow‐related muscles activities remain unclear. The aim of this study was to investigate the effects of sole‐ground contacts on the muscle activities during swallow for various materials; 26 healthy adult subjects participated in this study. Three different sole‐ground contact conditions were investigated; sole‐ground contact with knees bent to 90° (KB 90°), sole‐ground contact with knees bent to 135° (KB 135°), and sole‐ground off the floor (Off). Participants swallowed four bolus materials (saliva, 5‐ml water, 10‐ml water, and 5‐ml yogurt) in each sole‐ground contact condition. The muscular activities of the suprahyoid (SH) muscle and the sternocleidomastoid muscle during swallowing were detected and recorded using surface electromyography. The sole‐ground contact pressure was evaluated using the data acquisition system. Duration of SH during 10‐ml water swallow for Off was significantly longer than that for KB 90°. Duration of SH during 5‐ml yogurt swallow for Off was significantly longer than that for KB 90°. Integration of SH during 10‐ml water swallow for Off was significantly greater than that for KB 135°. Integration of SH during 5‐ml yogurt swallow for Off was significantly greater than that for KB 90°. No significant differences were found in peak of SH. Sole‐ground contact conditions had significant effect on swallow‐related muscles activities. The stable sitting positions might be more advantageous for performing effective swallows compared with less stable sitting positions.

[Purpose] This study aimed to investigate the plantar contact condition in females and to clarify the relationship between the foot alignment and floating toes classified in static and dynamic conditions. [Participants and Methods] The participants were 122 females. We evaluated the plantar contact condition, calculated the floating toe score, and classified the floating toes of the participants. The floating toes were classified into improvable and unimprovable floating toe groups based on the floating toe score measured in dynamic conditions. Furthermore, foot alignment was evaluated in 35 participants randomized and extracted from the contact toe and the improvable and unimprovable floating toe groups. [Results] The Arch Height Index in the unimprovable floating toe group was significantly smaller than that in the improvable floating toe group. The digitus minimus varus angle in the unimprovable floating toe group was significantly larger than that in the improvable floating toe group. No significant differences were observed in other items. [Conclusion] This study revealed that the foot alignment between the improvable and unimprovable floating toe groups has different features. However, no significant difference was found in the foot alignment between the contact and floating toe groups. Henceforth, it is necessary to evaluate and classify floating toes considering the functional aspects.

[Purpose] This study aimed to classify the plantar contact condition during forward stepping by focusing on the medial and lateral toes and to elucidate the relationship between the classification and turning movement. [Participants and Methods] The participants were 38 females. The plantar contact condition during forward stepping was evaluated for all participants, and the results were used for the group classification. In all the classified participants, the ground reaction force (GRF) during turning movement was measured. [Results] At sidestep (SS) and cross-step (CS), the peak medial-lateral GRF was significantly smaller in the medial floating toe (MFT) group than in the contact toe (CT) group. At SS, the peak times of the medial-lateral GRF in the MFT and lateral floating toe groups were significantly lesser than those in the CT group. At CS, the push-off peak time of the anterior-posterior GRF was significantly lesser in the MFT group than in the CT group. [Conclusion] The results of this study confirmed that each group classified according to the floating toe classification during forward stepping has different characteristics with respect to the ground reaction force during the turning movement, particularly the medial-lateral ground reaction force and its peak time.

A railway switch is characterised by movable parts, discontinuities in rail geometry and non-uniformities in trackbed stiffness. This work aims to assess the performance of railway switches considering long-term degradation of trackbed support with trafficking. A vehicle-track interaction model capable of reproducing the longitudinal variation in support stiffness and changes in contact condition through the switch panel is used. Site measurements of bearer deflection at a selected S&C are used to back-calculate a trackbed stiffness and initialise dynamic simulations to determine wheel-rail and trackbed contact forces. The calculated trackbed forces are used as an input in an iterative process to estimate the evolution of long-term rail top level and irregularity growth. The model results are compared with measured rail irregularity growth and the model is shown to predict similar trends. Model results and measurements show that higher rates of track geometry degradation occur around the load transfer area. The use of Under Sleeper Pads is found to decrease differential settlement within the panel.

This paper aims at the influence of nonlinear equivalent conicity with the same nominal equivalent conicity on EMU (Electric Multiple Units) motion attitude based on the wheel/rail nonlinear contact theory. Four worn wheels were considered in this paper, it was found that wheels with same normal equivalent conicity had significant differences on wheel/rail interactions. A new evaluation method was proposed: based on statistics data, the wheel/rail contact condition was identified with “nonlinear factor” and “nonlinear equivalent conicity” derived by equivalent conicity range from 1 mm to 6 mm. Both field tests and simulations indicated that the normal equivalent conicity couldn’t accurately reflect the wear condition of wheel/rail contact. The proposed new indexes based on nominal equivalent conicity and the slope of equivalent conicity curve would reflect the nonlinear characteristics of wheel/rail contact more accurately. It is an effective method to evaluate the relationship between wheel/rail nonlinear contact condition and vehicle dynamic performance.

A passive support with a pivot mechanism was previously designed for increasing damping of the vibration modes of a flexible structure. Here, to investigate the influence of the contact conditions between the pivot support and a flexible plate, the contact area is discretised into line contacts using metal rollers. The effect of contact stiffness is also investigated using additional plastic rings. Impact hammering tests are conducted and measured dynamic compliances are compared. Machining tests are subsequently performed to confirm vibration suppression. The line contacts are found to exhibit good vibration suppression capability in both the vibration and machining tests.

In this paper, bending, longitudinal and torsional stiffness of an eccentric circumferential crack is investigated with taking into account contact condition on the crack surfaces based on fracture mechanics. Although several researches have analyzed stress intensity factors of symmetric circumferential crack, the stiffness of an asymmetric circumferential crack in different directions (along and perpendicular to eccentricity) regarding contact condition has not been studied by an analytical method until now. In this paper we aim to describe behavior of eccentric circumferential crack under axial loading and establish a relation between axial force and the resulting displacement vector. The twisting angle of asymmetric circumferential crack due to torsional loading is also calculated and compared to twisting angle of a symmetric crack. In order to simulate the local bending stiffness in the contact condition, nonlinear governing equations of bending stiffness associated to cracked beam section is developed by dividing it to strip elements and utilizing stiffness equations related to noncontact condition. It is validated by 3D finite element (FE) nonlinear model. Results show a significant compatibility between presented analytical and 3D FE methods. Moreover results of simulations show that without taking into account contact condition, axial, torsional and bending stiffness of symmetric and asymmetric circumferential crack are equal and radius of un-cracked area is the only influential factor.

The segmental joint of a shield tunnel lining is one of the most critical components to consider when designing the lining. In this study, the mechanical behavior of two types of segmental joints used in a water-conveyance tunnel was investigated through a series of full-scale laboratory tests. Experimental data show that joint behavior is greatly influenced by the details of joint section, loading conditions, and the contact conditions between the two adjacent segments of the joint. To understand the mechanism of the behavior observed in the experiments, a finite element model that explicitly models bolts, cast iron panels, and the initial contact condition was developed. The numerical results of the FE model matched well with the experimental data, and the effect of the contact between segments on the joint stiffness was quantified. Results show that even a small initial gap (e.g. 2 mm) between segments has a significant effect on the joint stiffness. These findings can provide important guidance on the design of concrete segmental linings for future water-conveyance tunnels.

As the core technology of petroleum extraction engineering in the 21st century, Solid Expandable Tubular (SET) technology is applied to drilling, well completion, and cementing. However, the expansion process for tubulars in site operation may well lead to stress concentration, leakage, or even fracture failure in thread joints of the tubular assembly due to the irregular deformation of thread teeth. With the aim of studying the issue with regard to the thread joint of J55 steel expandable tubulars, this study extended a series of finite element models using the commercial software ABAQUS to investigate the structural response of tubulars during the expansion process. The simulation results include the stress evolution, deformation of the thread joint of the tubular assembly, and the effect of expansion cone geometry on the expansion consequences. A laboratory experiment was performed to validate the validity of the simulated solution. It was found from results that both the axial and hoop compressive stress concentrations were generated in the thread teeth edges near the contact surfaces of threads during the expansion process due to the mutual squeezing of box and pin thread teeth. An increase of the tubular diameter led to a reduction of wall thickness and axial length due to the law of volume-constancy. The expansion process resulted in a deterioration of the contact condition between the thread teeth. A cone angle of 9° and sizing section length of 65–75 mm were the optimal choice of the geometric size of the expansion cone according to their superior analytical results.

金沢大学理工研究域環境デザイン学系, Analytical models were prepared and results from these models were compared with experimental results to confirm the adequate modeling of steel-reinforced concrete members used in rockfall-protection galleries or rock-sheds. Static loading tests of steel-reinforced concrete members (a girder and a slab) were conducted on a simply supported beam. The analytical models have different contact conditions to verify which condition can express a semi-composite behavior and shear slide. Three types of contact conditions were applied: normal, tied, and tiebreak contact. Tiebreak contact can express the occurrence of gaps by defining shear bond strength. Consequently, analytical models that applied tiebreak contact showed comparatively good agreement with experimental results. Analytical models that applied the tiebreak contact condition showed a correlation of 97% (girder) and 101% (slab) with the experimental results for the maximum load-carrying capacity. Therefore, considering that slippage occurs between different materials, the model is good for expressing the behavior of complicated structures such as steel-reinforced concrete members that are used as a rock-shed. Copyright © 2017 ISEC Press., Embargo Period 12 months, 9th International Structural Engineering and Construction Conference: Resilient Structures and Sustainable Construction, ISEC 2017; Universitat Politecnica de Valencia - School of Civil EngineeringValencia; Spain; 24 July 2017 through 29 July 2017; Code 129215

In the material designing process of footwear outer-soles, the rubber grip property under lubricated conditions is important. Generally, friction behaviors of rubber under such conditions are influenced by contact states, which can be changed by various factors, i.e. viscosity, sliding velocity, normal force, surface roughness and wettability between two substrates. To discuss the influences of each parameter, the contact conditions are investigated. The purpose of this study is to establish a new method to measure the distributions of real contact area and film thickness between two substrates based on the decay behavior of an evanescent field in a total reflection method. In conclusion, film thickness was measured with an accuracy of 1 nm in a range of clearance of less than 800 nm.

Based on the traditional Archard wear theory, a novel wear model of ball screws was established by considering the actual contact condition between the ball and the raceway. According to the stress strength interference theory and the improved first-order second-moment method, the model of the reliability and sensitivity of the wear resistance of ball screws was proposed. The numerical example of both the reliability and sensitivity of a typical miniature ball screw (1004) in a small satellite was presented. The unit sensitivity was defined and proposed to better indicate the influence of different parameters on the wear resistance of ball screws, based on which the 1004 ball screw was redesigned and the wear resistance reliability of the ball screw was improved by 21%.

No natural language can enjoy the status of a completely isolated language. This is due to their always being in some kind of contact condition with other natural languages. As they all occur in the Natural Language Global Arena, they may either win, lose in competition with other languages, or receive the equal status. The different ‘statuses’ of natural languages are owed to the feeding and seeding processes in which they participate. The said processes are framed by the communication orders in which the particular natural languages happen to function. In turn, the communication orders in which the languages are functioning, appear to be decisive in either strengthening or weakening the robustness of every natural language in their sustainability.

Conventional eccentrically braced frames dissipate seismic energy through plastic deformation of link beams. However, large residual deformation after strong earthquakes often makes the damaged structure necessary for costly repair. This paper proposes a self-centering eccentrically braced frame system which incorporates shape memory alloy bolts and post-tensioned high strength steel tendons to provide a self-centering response behavior with moderate energy dissipation. An analytical model which has taken into account the super-elastic constitutive of shape memory alloys and the changing contact condition at the link-beam interface is formulated to predict the cyclic load behavior of the system. The feasibility of the proposed concept is demonstrated by cyclic load analysis of a prototype self-centering eccentrically braced frame. Finite element simulations are carried out to verify the analytical model and to further investigate the effects of the configuration details of the link-to-beam connection to the cyclic performance of the self-centering EBF system.

An inflatable cuff wrapped around the upper arm is widely used in noninvasive blood pressure measurement. However, the mechanical interaction between cuff and arm tissues, a factor that potentially affects the accuracy of noninvasive blood pressure measurement, remains rarely addressed. In the present study, finite element (FE) models were constructed to quantify intra-arm stresses generated by cuff compression, aiming to provide some theoretical evidence for identifying factors of importance for blood pressure measurement or explaining clinical observations. Obtained results showed that the simulated tissue stresses were highly sensitive to the distribution of cuff pressure on the arm surface and the contact condition between muscle and bone. In contrast, the magnitude of cuff pressure and small variations in elastic properties of arm soft tissues had little influence on the efficiency of pressure transmission in arm tissues. In particular, it was found that a thickened subcutaneous fat layer in obese subjects significantly reduced the effective pressure transmitted to the brachial artery, which may explain why blood pressure overestimation occurs more frequently in obese subjects in noninvasive blood pressure measurement.

Stigma surrounding mental illness and mental health treatment remains a significant problem, particularly among African Americans. This study sought to examine the effects of 2 intervention delivery methods in reducing reported stigma. African Americans (n = 158) were nonrandomly assigned to an in-person contact or video condition and administered a survey immediately before, after, and 2 weeks following the stigma intervention. The in vivo contact condition consisted of an African American man discussing his experiences with mental illness and psychotherapy. The session was recorded, and the recording was used for the video condition. There were no significant effects based on delivery method; however, there was a significant effect for time on stigma and help-seeking attitude measures. Further research is needed to determine the overall effectiveness of the intervention.

The risk of wheel-climb derailment increases if the traction coefficient in the wheel/rail contact is too high. This has been observed to happen more frequently just after wheel machining. This work investigates how the traction coefficient rises with evolution of the wheel/rail interface during the running-in. Experiments were performed using a full-scale wheel/rail contact rig and an ultrasonic array transducer mounted in the rail. Results were used to determine the stiffness of the contact interface. Contact stiffness appeared to be positively correlated with the traction coefficient. Owing to the conforming of the interface, contact stiffness increases before the traction coefficient rises. The work will allow recommendation of wheel machining to be made to help reduce the problem of wheel-climb derailment.

For four types of railway rails, corresponding rolling tests have been executed by using the JD-1 wheel/rail simulation device based on the Hertz simulation method, which can ensure the reciprocal contact condition between simulation rail and wheel under experimental conditions approximate to practical contact conditions. The results indicate that, for the rail material which has a higher hardness, the wear volume was less and the plastic deformation layer was thinner after the rolling test, but the crack propagation was more significant and the fatigue damage was severer, showing that its wear resistance was better. The analysis shows that the fatigue resistance of U71Mn rail was better, and considering fatigue is the main failure type for high-speed rail, so it is more suited to the high-speed railway.

This article describes a numerical model for coupled tyre–pavement interaction at static as well as rolling contact condition based on a finite element (FE) formulation. Beneficial of this modelling is that both contacting structures, the tyre as well as the pavement, are modelled under consideration of all relevant structural parts and, therefore, in a realistic manner. The coupled computation is realised by a programme interface that connects tyre and contact simulation in a commercial FE code to pavement simulation in an inhouse FE code. While the coupling for static contact is based on a standard Lagrangian formulation, the coupling of the elastic tyre at steady-state rolling and the inelastic pavement is realised by the introduction of an arbitrary Lagrangian Eulerian (ALE) formulation. A novelty is the implementation of interface elements into the ALE pavement model to describe the layer bonding behaviour. The potential of the coupled modelling for pavement investigations is demonstrated by two exam...

This study provides the general methodology describing the propensity of friction noise in ball joint system. The dynamic ball joint model is theoretically proposed under the concentric loading condition with nonlinear friction curve. In ball joint system, contact condition becomes non-conformal due to clearance between the ball head and cup. The results from stability analysis reveal that the ball joint system becomes dynamically unstable under the sufficiently small contact area and a negative friction-velocity slope. It is also shown that the lower bending modes of the beam have the higher propensity for modal instability.

In Kyoto downtown district, the ‘Road Contact Failure’ of the traditional Alley space is considered as a big hazard, regarding the disaster prevention and evacuation. This paper has focused on the transformation process of the Road Contact Failure area, by clarifying the changes in the road contact conditions, the site form as well as the relationship between each other. Further discussion is given on the challenges point towards the rescue techniques applied in Road Contact Failure area by revealing the factor which caused the changes in the road contact condition and the site form, not only in a comprehensive city level, but also in a specific site level. To conclude, it is found that there is a mutual relation between the road contact conditions in the target site and the ones in the peripheral site. Moreover, regarding the application of the deregulation, it was pointed out that the existing road contact conditions in both the target site and the peripheral site should be considered.

This paper studies the method for measuring the loop resistance of GIS conductor pole based on the super capacitor producing impulse current up to several thousand amperes. This method overcomes the limitations of conventional diagnostic method. Typical GIS conductor poles are chosen. Based on FEA and lab tests, the effect of different forms of current and contact condition, relationship between the temperature of contact and the loop resistance is researched. In full- scale testing under realistic operating conditions on the new 220 kV GIS using prototype instrumentation a very good sensitivity in an early stage was obtained.

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.

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.

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.

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.

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.

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.

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.

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 study compares two methods for model scale testing of ferrous/non-ferrous tribocouples under large area conformal contact condition, the kind existing in engine components such as journal bearings. Results show that the ring-on-disc method is better suited to visualise the performance of such tribosystems compared with the pin-on-plate method. The former offers greater sensitivity to minor changes in coefficient of friction and contact potential and is able to determine the thermal stability of the tribosystem under given conditions. Post-test surface characterisation revealed protective phosphorus-rich tribofilms on the surface of the steel counterparts from both test methods. Copyright © 2012 John Wiley & Sons, Ltd.

Purpose The aim of this study was to examine the effect of nonfunctional tooth contact on sensory threshold (tactile detection threshold: TDT) and pain thresholds (filament-prick pain detection threshold: FPT; pressure pain threshold: PPT) in the orofacial region of patients with myofascial pain of the jaw muscles. Methods The study was performed on 36 subjects: 20 normal subjects and 16 patients. Using a stair-case method, TDT and FPT were measured by Semmes–Weinstein monofilaments, on the cheek skin (CS) overlying the masseter muscles (MM) and on the skin overlying the palm side of the thenar skin (TS). PPT was measured at the central part of the MM using a pressure algometer. Each parameter was measured before and after keeping light tooth contact for 5 min (session 1) and keeping the jaw relaxed for 5 min (session 2) as a control. Results There were significant effects of experimental condition (before–after 5 min) on the TDT and FPT at several sites: after 5 min, TDT was higher in all measurement sites except the left CS of the patients in session 2. As for the FPT, the reactions between CS and TS were quite opposite in both sessions: after 5 min, the FPT at the CS decreased and/or remained, but the FPT at the TS increased and/or remained. Significant session effects (session 1–session 2) were only found on the FPT at the CS in patients. Conclusion Sensitivity to FPT was more susceptible to tooth contact condition, especially in the patients., Journal of Prosthodontic Research, 56(2), pp.87-92; 2012