• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.6
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• pp.1807-1818
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• 1991

The frictional characteristic of Zn-Ni electrogalvanized steel sheet was investigated by experimental procedures. To clarify the effect of surface property on the frictional characteristic of Zn-Ni coated steel sheet, Micro-hardness test, SEM analysis and X-ray diffraction analysis were carried out. Coefficients of friction for various stamping lubricant and Ni content in coated layer were measured by a draw bead friction test. The results show that frictional characteristic is very sensitive to Ni content of coated layer and depends on stamping lubricant. For Ni content less than about 11%, selection of proper lubricant is necessary to obtain low coefficient of friction in Zn-Ni coated steel sheet such as in case of cold rolled steel sheet.

• Transactions of Materials Processing
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• v.17 no.6
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• pp.401-406
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• 2008

The frictional behavior of stamping process is a function of interface parameters such as sheet and tool material, lubricant, surface roughness, contact pressure, sliding speed etc. Among these parameters the thing that can be controlled by a steel maker is the surface roughness of sheet. In this study, effects of surface roughness on the frictional behavior of steel sheet for automotive were investigated to find out the way to improve the frictional characteristics of steel sheet. The cold rolled steel sheets with various surface roughnesses were prepared for the test. The flat type friction test was conducted with different lubricant conditions. The surface roughness effect on frictional behavior depends on the viscosity of lubricant. The frictional characteristic of steel sheet was influenced by the amplitude of roughness as well as the shape of that.

• Science of Emotion and Sensibility
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• v.8 no.4
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• pp.385-391
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• 2005

A frictional coefficients of in-vivo skin characteristic is the most important factor of the cutaneous mechanical properties ant the method of evaluating skin care in the fields of cosmetics products. In-vivo skin characteristic varies in many different ways depends on what is applied to the skin, loading condition, shape, surface roughness, and material of the probe. In this research, we designed a system which can be measured frictional coefficients of a human skin on real time. It consists of multi-components load-cell, actuator, linear motor and arm fixator. This measurement system was automatically controlled by computer. We measured frictional coefficients between probe an4 skin using this system ant inquired adjectives for subjective evaluation while rubbing cosmetic product on skin. Lastly, we analyzed correlation between two factors by calculating Pearson Correlation Coefficient. As a result, we could know that frictional coefficients varied from 0.17-1.2 according to cosmetic products, normal forte, materials and surface conditions of probe. We also confirmed sensual feelings of cosmetic products have close correlation with frictional coefficients.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.101-106
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• 2005

During braking at a train, thermal energy is generated due to the frictions between disk and lining and wheel and shoe. In general, the braking transfers the kinetic energy into thermal energy. Therefore. the frictional characteristics are varied according to the braking force, the thermal resistance, and the thermostable, etc. Using a Dynamo testing we have studied the frictional characteristics and the thermal distribution to investigate a stable speed and to improve the testing method through comparing and analysing in the measurement or the thermocouple temperature and infrared camera.

• The korean journal of orthodontics
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• v.28 no.1 s.66
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• pp.123-133
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• 1998

The effectiveness of TiN ion-plating was examined with TiN ion-plated Co-Cr wires(.016“, .016”x.022“) on three different types of bracket(TiN ion-plated metal bracket ceramic bracket and plastic bracket). Maximum static frictional forces and characteristic curves obtained from the frictional characteristic graph, were compared and surface roughness of wires and bracket slots before and after friction experiment was observed by SEM. The obtained results were as follows $\cdot$The frictional forces of TiN ion-plated wires were significantly lower than those of non ion-plated wires(p<0.05). $\cdot$On the effect of wire shape, the frictional forces of round wires were significantly lower than those of rectangular wires(p<0.05) $\cdot$As the result of the SEM observation on the wires and bracket slots after the friction experiment the surface of non ion-plated wires was rougher than that of TiN ion-plated ones. $\cdot$The difference between the static frictional forces and the kinetic frictional forces was not significant in case of the TiN ion-plated round ins, but the static frictional forces were a little higher than the kinetic frictional forces in the TiN ion-plated rectangular wires. $\cdot$The static frictional forces were much higher than the kinetic frictional forces in the case of non ion-plated wires.

• Transactions of the Korean Society of Mechanical Engineers
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• v.5 no.4
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• pp.338-346
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• 1981

Honing, lapping, polishing and superfinishing are applied for a precision machining to finish the metal surface, but these precision machining are micro-cutting by hard and micro-abrasive grains. Frictional machining is the new method to finish mirrorlike surface without using those abrasive grains. The frictional machining produces high pressure and high temperature instantly by compressing a tool material against the metal surface in sliding motion. The metal surface is given plastic deformation and plastic flow by the above mentioned frictional motion, but the surface roughness of the metal surface is influenced by physical and chemical reaction in surrounding atmosphere. Therefore, the atmosphere around the metal optimum atmosphere in the frictional machining. The part 1 of the study was performed in liquid atmospheres. Diesel oil, lubricant, grease, lard oil, bean oil and cutting fluid were used as such atmospheres. Medium carbon steel SM 50 C was used as a workpiece and ceramic tip was applied as a frictional tool. The result of the experiment showed characteristic machining conditions to generate the best surface roughness in each atmospheres.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.116.2-116
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• 2002

$\textbullet$ Introduction $\textbullet$ Teleoperation System $\textbullet$ Stiffness Identification $\textbullet$ Frictional Characteristic Identification $\textbullet$ Conclusions

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.12
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• pp.1107-1114
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• 2008

This paper is aimed to understand the effect of different galvannealing temperatures on the frictional properties and Fe-Zn intermetallic phases of the galvannealed (GA) coatings on steel sheets. Their galvannealing treatments were conducted at 465, 505, 515 and $540^{\circ}C$ for about 10s in the additional heating furnace of an industrial continuous hot-dip galvanizing line. The mechanical and the frictional properties of the coatings were estimated using nanoindentation, nanoscratch, micro vickers hardness tests and flat friction tests, which were performed at contact pressures of 4, 20 and 80MPa. Also, the correlation between the microstructure and the frictional properties of the GA coatings were investigated by SEM observation for the cross-section of the GA coating after and before flat friction tests. The results showed that the mechanical and the frictional properties of the coatings are strongly dependent on their phase distributions and microstructure. Especially, in low contact pressure of 4MPa the frictional properties of the coatings were dependent on the surface phases and morphology, while in high contact pressure of 80MPa it was influenced by their mechanical properties based on the dominant phase distributions.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.9 no.1
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• pp.93-98
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• 2010

The metal fastening method is the new technology to repair cracks in the casting material using specially designed reverse screws. In this study, we conduct the finite element analysis to analyze the pulling force characteristic of a reverse screw, the core component of the metal fastening method, with respect to the change of the applying torque, frictional coefficient and front screw angle. The simplified analysis model with single screw pitch is proposed for convergency of the non-linear contact analysis. As a results, the pulling force of a reverse screw increase in proportion to the applying torque but exponentially decrease according to frictional coefficient. And also we can find the optimum front screw angle with the largest pulling force is $20^{\circ}$.

• Journal of the Ergonomics Society of Korea
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• v.29 no.2
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• pp.217-224
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• 2010

Research has been conducted to examine the effects of mechanical and sound characteristics of fabrics on affective quality. The present study developed the Affective Quality Evaluation and Estimation System for Textiles (AQEEST) with distinguished features that can be effectively used in the affective research of fabric frictional sound. The AQEEST consists of three subsystems (affective quality evaluation, affective quality estimation, and audible distance estimation subsystems) and each subsystem consists of three to four modules (e.g., evaluation condition setup, evaluation experimentation, and textile database management modules) depending on its functional requirements. The affective quality evaluation subsystem was designed to help administer an experiment in a systematic manner and present acoustic and visual stimuli simultaneously in various gait conditions (walking, jogging, and running) to mimic a more realistic situation of textile frictional sound production. Next, the affective quality estimation subsystem was designed to estimate the sound characteristics, affective qualities, overall psychological satisfaction, and reference cluster of a textile using its mechanical and/or sound characteristic information. Lastly, the audible distance estimation subsystem was designed to estimate the just noticeable sound pressure levels and audible distances of a textile for various gait conditions using its mechanical characteristic information. The AQEEST can be upgraded by accommodating more affective quality study results for various textiles.