• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.39 no.11
• /
• pp.1131-1136
• /
• 2015

In a diesel engine, the wear of the cylinder liner occurs because of the continuous reciprocating motion of the piston ring. This wear reduces the performance of the diesel engine and shortens its service life. This study evaluated the wear characteristics of GT metal and a conventional metal used for cylinder liners using a ship's diesel engine. Wear tests were performed at temperatures of $25^{\circ}C$, $175^{\circ}C$, and $325^{\circ}C$, and under loads of 10 N, 30 N, and 50 N. The amount of wear, specific wear rate, and friction coefficient were evaluated for each condition. To analyze the wear mechanism, observations were made on an SEM. In the case of both metals, abrasive and adhesion wear occurred on the wear surfaces at room temperature, and corrosion wear was observed at high temperatures. The amount of wear and the specific wear rate of the GT metal were lower than those of the conventional metal at all temperatures, and hence it can be concluded that the wear characteristics of the GT metal are much better.

• Tunnel and Underground Space
• /
• v.34 no.2
• /
• pp.143-153
• /
• 2024

Tunnel Boring Machine (TBM) method is a tunnel excavation method that produces lower levels of noise and vibration during excavation compared to drilling and blasting methods, and it offers higher stability. It is increasingly being applied to tunnel projects worldwide. The disc cutter is an excavation tool mounted on the cutterhead of a TBM, which constantly interacts with the ground at the tunnel face, inevitably leading to wear. In this study quantitatively predicted disc cutter wear using geological conditions, TBM operational parameters, and machine learning algorithms. Among the input variables for predicting disc cutter wear, the Uniaxial Compressive Strength (UCS) is considerably limited compared to machine and wear data, so the UCS estimation for the entire section was first conducted using TBM machine data, and then the prediction of the Coefficient of Wearing rate(CW) was performed with the completed data. Comparing the performance of CW prediction models, the XGBoost model showed the highest performance, and SHapley Additive exPlanation (SHAP) analysis was conducted to interpret the complex prediction model.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 1998.04a
• /
• pp.64-68
• /
• 1998

본 연구에서는 다양한 종류의 섬유를 일방향으로 배향시켜 제작한 복합재료의 트라이볼로지 연구를 수행하였으며 특히 섬유의 배향과 활주속도가 트라이볼로지 성질에 미치는 영향을 연구하였다. 실험에 쓰인 시편은 유리 섬유, 아라미드 섬유, 그리고 고탄성 탄소 섬유를 보강재료로 에폭시 수지를 모재로 사용한 일방향섬유 복합재료이며 각각의 시편을 스테인레스 강 상대 마찰면에 마찰시켜 마모량과 마찰 계수를 구하였다. 실험조건으로 사용한 여러 활주속도에서 탄소섬유복합재료가 모든 섬유배열방향에서 아라미드섬유복합재료와 유리섬유 복합재료보다 마모율과 마찰계수가 낮은 경향을 보였으며 특히 높은 속도에서는 탄소섬유복합재료의 특성이 뛰어남을 알 수 있었다.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2011.06a
• /
• pp.625-626
• /
• 2011

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.38 no.5
• /
• pp.469-474
• /
• 2014

The high temperature gas-cooled reactor (HTR-10) is designed to produce electricity and hydrogen. Graphite is used as reflector, support structures, and a moderator in reactor core; it has good resistance to neutron and is a suitable material at high temperatures. Friction is generated in the graphite structures for the core reflector, support structures, and moderator because of vibration from the HTR-10 fuel cycle flow. In this study, the wear characteristics of the isotropic graphite IG-110 used in HTR-10 were evaluated. The reciprocating wear test was carried out for graphite against graphite. The effects of changes in the contact load and sliding speeds at room temperature and $400^{\circ}C$ on the coefficient of friction and specific wear rate were evaluated. The wear behavior of graphite IG-110 was evaluated based on the wear surfaces.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.19 no.5
• /
• pp.125-133
• /
• 2011

The wear of rubber track being in contact with the road surface is an important subject because it decreases the traction performance and the operating efficiency of tracked vehicle. For the above reasons, many attempts have been made to quantitatively calculate the rubber track. However, it depends on the experimental methods which are highly time- and cost-consuming. Therefore, the numerical simulation approach is highly desirable, but it needs to model the complex geometry and the material behavior in details as well as the interaction with the road surface. In this study, the rubber track and its material behavior are elaborately modeled since these factors are very important in the prediction of the wear rate of the rubber track. Accordingly to the studies on the rubber wear by previous investigations, it has been found that the wear is greatly influenced by the frictional energy. The frictional energy of rubber track is computed by utilizing the 3D finite element analysis of the rubber track, and the wear rate is evaluated making use of the frictional energy and a wear model.

• Proceedings of the KAIS Fall Conference
• /
• 2006.05a
• /
• pp.180-183
• /
• 2006

엔진 밸브와 밸브시트의 마모는 엔진 성능에 영향을 미치는 가장 중요한 요소 중에 하나이다. 엔진 밸브와 밸브시트는 엔진 구동 과정에서 발생하는 고온의 배기가스, 밸브 스프링의 빠른 움직임, 엔진 폭발 과정의 고압, 균일하지 못한 냉각시스템으로 발생하는 실린더 헤드의 뒤틀림이 만들어 내는 극한 환경을 이겨내야 한다. 본 연구에서는 밸브 및 밸브시트의 마모율과 마모 메카니즘을 명확하게 규명하기 위해서 실제 자동차 엔진 내부의 조건인 온도, 밸브와 밸브시트간의 충돌, 스라이딩 등에 관한 것들을 고려하여 밸브 및 밸브시트가 충돌 시험할 수 있는 전용마모 시험기를 사용하였다. 본 연구에 사용된 시편은 현재 실차에 사용되고 있는 밸브와 밸브시트를 사용하였다. 그 종류는 STR35 밸브, STL #6 및 STL #32이다. 밸브시트는 HVS1-2 재질을 사용하였다.

• Journal of the Korean Society for Railway
• /
• v.10 no.5
• /
• pp.607-612
• /
• 2007

In this paper, operation mode of train was divided into powering, coasting, and braking and rail wear phenomenon has been done comparative analysis by each section. Data of train velocity is transferred to acceleration and deceleration from ATO Logging data. Amount of rail wear has been done comparative analysis by traction force of acceleration and braking force of deceleration and a plan for management of track irregularity is come up with by the result of the analysis.

• Korean Journal of Materials Research
• /
• v.4 no.7
• /
• pp.733-740
• /
• 1994

Oxidized-PAN fiber reinforced composite(OFRP), carbon fiber reinforced composite(CFRP), aramid fiber reinforced composite(AFRP), and glass fiber reinforced composite(GFRP) were fabricated with phenolic resin matrix by hot press molding. We tested the friction coefficient and wear rate varying with fiber weight fraction and observed the effect of fibers according to characteristics of individual reinforcement. When the amount of aramid fiber was 45wt%, average friction coefficient was maximum value of 0.353~0.383, where as, when the amount of pitch based carbon fiber was 45wt%, average friction coefficient was the lowest value of 0.164~0.190. The wear rate of AFRP and CFRP was low, but that of GFRP and OFRP increases drastically in the case of increasing of fiber weight fraction. Wear diagram of OFRP was unstable, but that of CFRP and AFRP was a bit stable. Through very unstable diagram of GFRP, we found that friction stability of GFRP was the lowest.

• The tire
• /
• s.144
• /
• pp.6-7
• /
• 1989

과마모 타이어의 사용으로 인한 사고발생의 위험을 미연에 방지하기 위하여 미국, 일본 등에서는 오래 전부터 타이어의 마모한계를 법제화하여 이를 시행하고 있다. 우리나라에서도 자동차보유대수의 급증에 따라 타이어의 결함으로 인한 사고발생율이 높아지고 있는 현실을 감안, 교통부에서는 지난 4월 「자동차안전기준에 관한 규칙」개정시 이에 대한 대책의 일환으로 타이어 관계조항(규칙 제12조2항)을 개정, 타이어 트레드 홈깊이를 1.6mm 이상 유지하도록 규정하였으며, 이 개정된「자동차안전기준에 관한 규칙」의 시행을 눈앞에 두고 있다.<필자주>