지하철 레일의 미끄럼 마모거동을 고려한 재료설계에 대한 고찰

이한영(Han-Young Lee) 한국트라이볼로지학회 2014 한국윤활학회지(윤활학회지) Vol.30 No.6

To assess the wear behavior of rails against subway rail car wheels, we investigate the sliding wear behavior of pins derived from two types of rails (normal rails and heat-treated rails) against a disc derived from a subway rail car wheel, using a pin-on-disc-type tribometer. We base the sliding wear test conditions on the sliding conditions for wheel flange? rail gauge corner contact. We demonstrate the remarkable transition in the wear behavior of the pins derived from the rails, from severe wear to mild wear, as a function of the sliding distance. The wear rate of the heat-treated rail material in the running-in wear region is much lower than that of the normal rail material. Furthermore, the wear rates of the pins in the running-in wear region decrease with increasing hardness and with decreasing sliding speed. However, there is little difference between the heat-treated rail pin and the normal rail pin in the wear rate in the steady-state wear region. Stricter controls on the decarburized layer beneath the surface of rails are required to reduce the wear rate in the running-in wear region.

Study on the Slide-Ring Material reinforced EPDM Rubber Composites

김규리,오정석,조용원,김혜영,강동국,( Pranabesh Sahu ) 한국공업화학회 2021 한국공업화학회 연구논문 초록집 Vol.2021 No.-

Review on the Influence of Different Reinforcements on the Microstructure and Wear Behavior of Functionally Graded Aluminum Matrix Composites by Centrifugal Casting

Bassiouny Saleh,Jinghua Jiang,Aibin Ma,Dan Song,Donghui Yang,Qiong Xu 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.7

The main objective of the present paper is to draw the attention of researchers towards the wear analysis of functionallygraded aluminum matrix composites (FGAMCs) reinforced with different types of particles. The quality of the productsand characteristics achieved by the functionally graded materials (FGMs) has been given increasing attention during recentdecades. FGMs provide a way to obtain gradients between two phases with variations of properties. The centrifuge castingprocess was used to produce continuous variation of graded materials. These continuous graded materials offer high strengthand enhanced wear resistances compared with traditional composite materials. This paper summarizes the effect of the variousreinforcement materials and wear test parameters on microstructure as well as wear properties in the FGAMCs obtainedthrough the centrifugal casting technique. The results found in the reviewed literature are classified according to types ofreinforcement particles (such as silicon carbide, alumina and boron carbide) and the influence of wear test parameters (suchas applied load, sliding distance, duration and sliding speed) on FGM composites. The main conclusions in this paper arederived from previous studies on experimental investigations on the wear characteristics of FGAMCs. The research gapsand future directions have been discussed which will be prolific to the researchers in the design and manufacture of FGMsproduction by centrifugal casting.

Apply Adaptive Fuzzy Sliding Mode Control to SMA Actuator

Nguyen Trong Tai,Kyoung Kwan Ahn 제어로봇시스템학회 2010 제어로봇시스템학회 국제학술대회 논문집 Vol.2010 No.10

In this paper, an adaptive fuzzy sliding-mode controller (AFSMC) is proposed to control SMA actuator. An approach of self-tuning fuzzy sliding-mode control which combines fuzzy control with the sliding-mode control (SMC), is presented for the tracking control of a class of nonlinear systems with the parameter uncertainties. Based on Lyapunov theory, the asymptotic stability of the overall systems is proved. The controller is applied to compensate the hysteresis phenomenon of SMA. The control results show that the controller is applied successfully to SMA.

Effect of surface contact conditions on the stick-slip behavior of brake friction material

Yoon, S.W.,Shin, M.W.,Lee, W.G.,Jang, H. Elsevier Sequoia [etc.] 2012 Wear: An international journal on the science and Vol.294 No.-

Brake-induced stick-slip, which determines the propensity of a brake system to generate noise, was investigated by analyzing the friction oscillation at different loads, speeds, and surface topographies. The friction characteristics at the sliding interface were obtained using a pad-on-disk type tribometer and a 1/5-scale brake dynamometer. Results showed that the size and stiffness of the surface contact plateaus significantly affect the propensity of stick-slip and wear. The stick-slip amplitude increased with normal load and decreased with sliding speed. Contact stiffness of the friction material, which was modified by producing shallow slots on the rubbing surface, also strongly affected the stick-slip propensity, whereas Δμ(=μ<SUB>s</SUB>-μ<SUB>k</SUB>) was not changed by the surface modification. The strong effects from the contact stiffness suggest that the height distribution of the surface plateaus can change the stick-slip propensity of a brake friction material.

Search for Sliding Surface of Slope Based on Dynamic Strength Reduction Method

( Guoqing Chen ) 대한지질공학회 2019 대한지질공학회 학술발표회논문집 Vol.2019 No.2

The failure of slope is a progressive process where the whole sliding surface gradually evolves from the local damaged region in the slope. Based on the yield weakening of geotechnical material, a new sliding surface search method that can simulate the progressive failure of slope was proposed. The strength parameter of the damaged region was reduced, and then mechanical equilibrium of slope was calculated. Through the continuous local damage reduction of the strength parameters of the damaged slope body, the potential sliding surface damaged gradually and evolved to breakthrough finally. The weak layer is closely associated with the stability of the heterogeneous rocky slope, but traditional calculation method is difficult to determine the failure mode. Present article mainly deals with the analysis of the stability of Dagangshan Mountain slope of Sichuan Province in China. The prevention flow of sliding disaster for heterogeneous rocky slope is presented. At first, Dynamic Strength Reduction Method (DSRM) was used to search the sliding surface, failure position and sliding direction. The case study of Dagangshan Mountain slope shows that DSRM is reasonable and correct when it is compared with the field observations. The study indicates that the sliding disaster of the slope is connected with f231 fault. The calculation results provide theoretical basis for the support and reinforcement program. In conclusion, DSRM provides a new calculation method for the stability and disaster forecast of similar heterogeneous rocky slopes.

상대재 내식성이 철강재료의 미끄럼마모 특성에 미치는 영향

이한영(Han-Young Lee) 한국트라이볼로지학회 2019 한국윤활학회지(윤활학회지) Vol.35 No.2

This study investigates the effects of corrosion resistance characteristics of opponent materials in relative motion on the sliding wear behavior of mild carbon steel. Pin specimens made of mild carbon steel are tested at several sliding speeds against mating discs made of two types of alloyed steels, such as type D2 tool steel (STD11) and type 420 stainless steel (STS420J2), with different corrosion resistance characteristics in a pin-ondisc type sliding wear test machine. The results clearly show that the sliding wear behavior of mild carbon steel is influenced by the corrosion resistance characteristics of the mating disc materials at low sliding speeds. However, the sliding wear behavior at high sliding speeds is irrelevant to the characteristics because of the rising temperature. During the steady state wear period, the sliding wear rate of mild carbon steel against the type 420 stainless steel at a sliding speed of 0.5 m/s increases considerably unlike against the type D2 tool steel. This may be because the better corrosion resistance characteristics achieve a worse tribochemical reactivity. However, during the running-in wear period at low sliding speeds, the wear behavior of mild carbon steel is influenced by the microstructure after heat treatment of the mating disc materials rather than by their corrosion resistance characteristics.

Characteristics of Friction Behavior of Ceramic Friction Materials according to Surface Materials

박지훈,이정우,곽종원,한우진,한원일 한국건설순환자원학회 2023 한국건설순환자원학회 논문집 Vol.11 No.4

Friction material, an integral constituent of bearing supports, facilitates frictional interactions between two components. Polytetrafluoroethylene (PTFE), a commonly employed friction material in bearing supports, has assessed resultant friction equilibrium. Nonetheless, protracted utilization diminishes frictional performance as the lubricating agent is progressively depleted. Friction materials can affect the entire structural system. Hence, this study applied ceramic material as a friction material due to its high strength, low friction, and low deformation. The frictional behavior was investigated using a cyclic friction test, considering various friction materials as the primary design variables and examining their covariance in cyclic frictional movements. The results substantiated that the ceramic friction material yielded a low variance and friction coefficients in cyclic frictional movements.

Location determining method of critical sliding surface of fillings in a karst cave of tunnel

Lin, P.,Li, S.C.,Xu, Z.H.,Huang, X.,Pang, D.D.,Wang, X.T.,Wang, J. Techno-Press 2018 Geomechanics & engineering Vol.16 No.4

A location determining method is proposed for critical sliding surface in the stability analysis of the filling materials in karst caves. First, a preliminary location of the sliding surface is determined based on simulation results which includes displacement contour and plastic zone. The sliding surface will locate on the bottom contact interface when the friction angle is relative small. However, a weakened contact interface always becomes the critical sliding surface no matter what the friction angle is. Then when the friction angle becomes larger, the critical sliding surface inside fillings can be determined by a parabola, the coefficient of which increases linearly with the friction angle under the same cohesion. Finally, the critical sliding surface approximately remains unchanged with friction angle. The influence of cohesion is similar to that of friction angle. Although affected by shape, size or position of the karst cave, the critical sliding surface mainly depends on both friction angle and cohesion. Thus, this method is always useful in determining the critical sliding surface.

Sliding Wear and Corrosion Resistance of Copper-based Overhead Catenary for Traction Systems

Kwok, C.T.,Wong, P.K.,Man, H.C.,Cheng, F.T. The Korean Society for Railway 2010 International Journal of Railway Vol.3 No.1

In the present study, the electrical sliding wear and corrosion resistance of pure copper (Cu) and six age-hardened copper alloys (CuCr, CuZr, CuCrZr, CuNiSiCr, CuBe and CuBeNi) were investigated by a pin-on-disc tribometer and electrochemical measurement. Various copper-based alloys in the form of cylindrical pin were forced to slide against a counterface stainless steel disc in air under unlubricated condition at a sliding velocity of 31 km/h under normal load up to 20 N with and without electric current. The worn surface of and wear debris from the specimens were studied by scanning electron microscopy. Both mechanical wear and electrical arc erosion were the wear mechanisms for the alloys worn at 50 A. Owing to its good electrical conductivity, high wear and corrosion resistance, CuCrZr is a promising candidate as the overhead catenary material for electric traction systems.