• 수산해양기술연구
• /
• 제40권4호
• /
• pp.344-350
• /
• 2004

탄소 섬유강화 에폭시기지 복합재의 경면 가공한 스테인리스강 상대재와 마찰과 마모에 바탕을 둔 연구에서는 다음과 같은 결론을 얻었다. (1) 복합재의 비마모율은 하중이 증가하면 N방향와 P방향에서는 증가하는 경향을 보이며,AP방향에서는 감소한다. 이것은 마모 메카니즘의 영향으로 속도가 증가하면 마모 이착막의 생성이 빨라져 이착막 속의 탄소섬유가 윤활제의 역할을 하기 때문이다. (2) 복합재의 마찰계수는 하중이 증가하면 N방향과 AP방향에서는 하중 39.2N까지 증가하다가 그 이상의 하중에서는 감소되며 AP방향에서는 하중이 증가함에 따라 서서히 증가하며, 또한 그 값은 N방향에서 가장 크고, AP방향이 가장 적다. (3) 일방향 탄소섬유 강화 복합재의 마모 거동에 미치는 하중의 효과는 다르며 마찰초반에 발생한 섬유에 의한 쟁기질과 섬유 굽힘 및 미소크랙에 의한 섬유 균열과 파괴에 따른 마모 메카니즘의 형태에 의한 것이다.

• 한국윤활학회:학술대회논문집
• /
• 한국윤활학회 1999년도 제29회 춘계학술대회
• /
• pp.7-13
• /
• 1999

An experimental study was performed to discover the effect of silver coating on the frictional behavior of SM45C steel at sliding surfaces. Pure silver was coated the SM45C disk surfaces by a thermal evaporation method. Experiments using a pin-on-disk test-rig was performed under dry air and various humidity conditions. Friction coefficients increased to a high and unstable value after failure of coating, and friction coefficients increased with increasing the thickness of silver coated layer. But optimum coating thickness was not observed.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2005년도 춘계학술대회 논문집
• /
• pp.855-859
• /
• 2005

Carbon fiber polymeric composites have been widely used in bearing materials under high pressure without oil-lubrication due to their self-lubricating characteristics. However, the severe wear of carbon composite surface occurs due to the generation of wear debris when the pressure applied on the composite surface is higher than the critical value of composite surface. In this work, in order to remove wear debris continuously during sliding operation, composite specimens with many micro-grooves on their sliding surfaces were devised. To investigate the effect of wear debris on the tribological behavior of carbon/epoxy composites, dry sliding tests were performed with respect to applied pressure using the composite specimens with and without micro-grooves. From the measurement of friction coefficients and wear rates, a model for the effect of wear debris on the friction and wear of composites was proposed.

• Tribology and Lubricants
• /
• 제8권1호
• /
• pp.63-69
• /
• 1992

In order to gain better understanding of wear behaviors of TiN-coated boron cast iron, tests and analyses were conducted with block-on disc type tribometer. TiN layer of thickness $2 \mu m$ and $4 \mu m$, coated by cathodic arc evaporation process, were experimentally investigated with the variation of applied load and sliding speed under dry sliding condition. Wear characteristics were expressed in terms of the three-dimentional wear map as well as the wear rate vs sliding speed and load. Comparisons of wear and friction characteristics between coated cast irons and uncoated cast irns were also made. Wear mechanism of TiN layer was explained in view of surface interaction between the mating surfaces. The thicker coating exhibited higher hardness and adhesion strength. the significance of stresses at the surface and in the subsurface was briefly discussed in relation to the wear behavior.

• Journal of Mechanical Science and Technology
• /
• 제17권12호
• /
• pp.1904-1911
• /
• 2003

In order to determine the wear properties of AIP (Arc Ion Plating) deposition, wear process was evaluated by using a Falex test machine. Also, in order to determine the effects of coating material on the wear process, TiC, TiN, and TiCN coatings of thickness about 5 $\mu\textrm{m}$∼6 $\mu\textrm{m}$ coated by Arc ion plating deposition method were tested. The wear property was determined under a dry sliding condition as a function of the applied load, sliding distance, sliding velocity and temperature. The results show that when wear of the coating-layer occurred, specific wear amount increased with the wear rate. At initial state, the wear rate rapidly increased, but it gradually reduced as the velocity increased. Also, when raising the temperature, the wear rate increased in the order of TiCN, TiN and TiC due to the frictional heat.

• 한국윤활학회:학술대회논문집
• /
• 한국윤활학회 2001년도 제33회 춘계학술대회 개최
• /
• pp.313-318
• /
• 2001

The sliding wear behavior of Plasma-Sprayed Al$_2$O$_3$-TiO$_2$ Coating against Cemented Carbide were Investigated using a pin on disk type tester. The experiment was conducted using Al$_2$O$_3$-TiO$_2$ Coaling as pin material and Cemented Carbide as disk material and different operating conditions, at room temperature under a dry conditions. The results showed that the type B(250kw power) appeared average wear rate Is lowed than type A(80kw power). The specific wear rate of Specimen A1 Increased with normal load. But The specific wear rate of Specimen B1 decreased with normal load. Average wear rate of specimen A3, B3 are lowed than other but the sliding wear mechanism of edge were rough.

• Structural Engineering and Mechanics
• /
• 제23권3호
• /
• pp.293-308
• /
• 2006

This paper presents a complete and consistent formulation to study the seismic response of a free-standing ship supported by an arrangement of n keel blocks which are all located in a dry dock. It is considered that the foundation of the system is subjected to both horizontal and vertical in plane excitation. The motion of the system is classified in eight different modes which are Rest (relative), Sliding of keel blocks, Rocking of keel blocks, Sliding of the ship, Sliding of both keel blocks and the ship, Sliding and rocking of keel blocks, Rocking of keel blocks with sliding of the ship, and finally Sliding and rocking of keel blocks accompanied with sliding of the ship. For each mode of motion the governing equations are derived, and transition conditions between different modes are also defined. This formulation is based on a number of fundamental assumptions which are 2D idealization for motion of the system, considering keel blocks as the rigid ones and the ship as a massive rigid block too, allowing the similar motion for all keel blocks, and supposing frictional nature for transmitted forces between contacted parts. Also, the rocking of the ship is not likely to take place, and the complete ship separation from keel blocks or separation of keel blocks from the base is considered as one of the failure mode in the system. The formulation presented in this paper can be used in its entirety or in part, and they are suitable for investigation of generalized response using suitable analytical, or conducting a time-history sensitivity analysis.

• 한국자동차공학회논문집
• /
• 제9권4호
• /
• pp.131-138
• /
• 2001

In this paper, performance of a dry CVT vehicle with torque cam is investigated. Based on belt transmission mechanism and torque cam actuator characteristics, an algorithm which is able to calculate the speed ratio from given thrust and load torque is suggested and a 3-D map is constructed for the speed ratio-thrust-torque. Using the 3-D map, a steady state characteristic of torque cam and a transient response of a dry CVT vehicle are investigated by simulation. It is found that initial spring compression plays a key role in determining the sliding criteria and the speed ratio velocity.

• 제어로봇시스템학회논문지
• /
• 제11권6호
• /
• pp.502-509
• /
• 2005

In this paper, a 4-wheel vehicle model including the effects of tire slip was considered, along with variable parameter sliding control, in order to improve the performance of the vehicle longitudinal response. The variable sliding parameter is made to be proportional to the square root of the pressure derivative at the wheel, in order to compensate for large pressure changes in the brake cylinder. A typical tire force-relative slip curve for dry road conditions was used to generate an analytical tire force-relative slip function, and an antilock sliding control process based on the analytical tire force-relative slip function was used. A retrofitted brake system, with the pushrod force as the end control parameter, was employed, and an average decay function was used to suppress the simulation oscillations. The simulation results indicate that the velocity and spacing errors were slightly larger than those obtained when the wheel slip effect was not considered, that the spacing errors of the lead and follower were insensitive to the adhesion coefficient up to the critical wheel slip value, and that the limit for the antilock control under non-constant adhesion road conditions was determined by the minimum value of the equivalent adhesion coefficient.

• 한국윤활학회:학술대회논문집
• /
• 한국윤활학회 2004년도 학술대회지
• /
• pp.66-74
• /
• 2004

The sliding wear behavior of $ZrO_2-22wt\%MgO\;(MZ)\;and\;ZrO_2-8wt\%Y_2O_3\;(YZ)$ deposited on a casting aluminum alloy with bond layer (NiCrCoAlY) by plasma spray against an SiC ball was investigated under dry test conditions at room temperature. At all load conditions, the wear mechanisms of the MZ and the YZ coatings were almost the same. The wear mechanisms involved the forming of a smooth film by material transferred on the sliding surface and pullout. The wear rate of the MZ coating was less than that of the YZ coating. With an increase normal load the wear rate of the studied coatings increased. The SEM was used to examine the sliding surfaces and elucidate likely wear mechanisms. The EDX analysis of the worn surface indicated that material transfer was occurred from the SiC ball to the disk. It was suggested that the material transfer played an important role in the wear performance.