• Elastomers and Composites
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• v.58 no.2
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• pp.87-94
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• 2023

Abrasion tests of an SBR compound were conducted using four different types of abrasion testers (cut and chip, Lambourn, DIN, and LAT100). The abrasion test results were analyzed in terms of size distributions and morphologies of the wear particles. Most wear particles were larger than 1000 ㎛. The wear particle size distributions tended to decrease as the particle size decreased. Except for the Lambourn abrasion test, the wear particles smaller than 212 ㎛ were rarely generated by the other three abrasion tests, implying that small wear particles were produced through friction by introducing talc powder. Shapes of the wear particles varied depending on the abrasion testers. The wear particles generated from the Lambourn abrasion tester had stick-like shapes. The cut and chip abrasion test showed a clear abrasion pattern, but the DIN abrasion test did not show any specific abrasion pattern. The Lambourn and LAT100 abrasion tests showed irregular abrasion patterns.

• Elastomers and Composites
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• v.58 no.1
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• pp.17-25
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• 2023

Abrasion tests of model tire tread compounds (NR and NR/BR blend compounds) were performed at different slip angles (1° and 7°) using a laboratory abrasion tester. The abrasion behavior was investigated by analyzing the worn surface and wear particles. The abrasion spacing formed on the specimen worn at the large slip angle of 7° was significantly narrower than that at the small slip angle of 1°, while the abrasion depth for the specimen worn at 7° was lower than that at 1°. The abrasion spacing and depth tended to be narrower and lower, respectively, as the BR content increased. The abrasion patterns were clearly visible on the outside of the specimen for the slip angle of 1° but not for 7°. The wear particles had a rough surface and there were numerous micro-bumps. It was found that the crosslink density affected the abrasion patterns and morphologies of the wear particles.

• Elastomers and Composites
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• v.54 no.4
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• pp.313-320
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• 2019

A typical wear pattern was reported to resemble the fatigue crack growth behavior considering its mechanism, especially for amorphous rubbers such as styrene-butadiene rubber (SBR). In this study, the wear and crack growth rates were correlated using two separate experiments for carbon black and silica-reinforced selected rubber compounds. The wear rate was determined using a blade-type abrasion tester, where the frictional energy input during wearing was measured. The crack propagation rate was determined under different tearing energy inputs using a home-made fatigue tester, with a pure-shear test specimen containing pre-cracks. The rates of abrasion and crack propagation were plotted on a log-log scale as a function of frictional and tearing energies, respectively. Reasonable agreement was observed, indicating that the major mechanism of the abrasion pattern involved repeated crack propagation.

• The Journal of Korean Academy of Prosthodontics
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• v.40 no.2
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• pp.184-192
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• 2002

The purpose of this study was to investigate the abrasion resistance and surface roughness of conventional dental stones and improved dental stones and newly developed dental stones. Materials included in this study were several dental stones and newly developed dental stone; 2 type III. 6 type IV (including newly developed dental stone). 1 type V Ten specimens for each material, total ninety specimens were made. Each specimen was subjected to 50 complete cycle abrasion under constant load 0.42N at speed or 6mm per sec. The depth after abrasion test was measured for each specimen. Surface roughness before and after abrasion test was compared. The results were as follows ; 1. The resin containing die materials such as Tuff Rock and Resin Rock had superior abrasion resistance. 2. Type IV, V dental stone exhibited greater abrasion resistance than Type III dental stone. 3. The results or the surface roughness showed similar pattern with the abrasion resistance.

• Journal of Korean Tunnelling and Underground Space Association
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• v.3 no.4
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• pp.17-24
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• 2001

Four road tunnels of which the construction conditions were similar were selected in the paper, and laboratory tests and rockmass classification for the tunnels were carried out. And the analysis was performed to find out the correlation between ratio of bit abrasion or drilling parameter and support pattern of tunnel using jumbo drill machine. It was analyzed that there was average abrasion of bit from 11.85% to 3.25% per support patterns of tunnel in four tunnels. Drilling parameter happens to fluctuate according to extent of fracture zone.

• The Korean Journal of Emergency Medical Services
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• v.9 no.2
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• pp.137-146
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• 2005

This research focused on studying the phenomena of activity injuries occurred in military service, the object of which is soldiering soldiers in army. I made a inquiry paper including 6 items such as injury frequency, athletic event when you are injured, injury pattern, injury part in body and injury time according to military classes, and distributed it to elected 421 soldiers, the number of which is the total number of injured soldiers having time for physical activities in a year(last 2002 year). The results were as follows ; First, Injury frequency was according to private middle classes, private second classes, private last classes, private first classes. Second, Athletic event when you are injured was according to soccer, basketball, running and Martial Art(Taekwondo). 1) An abrasion was the most injury pattern when playing soccer. 2) A sprain was the most injury pattern when playing basketball. Third, Most causes of injuries dued to his / her carelessness, which is his / her excessive greed to win. Fourth, The most injury pattern was a skin abrasion. Fifth, The most injury part in body was a leg. Sixth, There was the most injury in summer. Wednesday on week, especially afternoon when you have time for physical to improve your battle-power.

• Journal of the Korean Society of Safety
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• v.23 no.6
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• pp.7-13
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• 2008

It is important to prevent roll failure in hot rolling process for reducing maintenance cost and production loss. The relationship between rolling pass schedule and the work roll wear profile will be presented. The roll wear pattern is related with roll catastrophic failure. The irregular and deep roll wear pattern should be removed by On-line Roll Grinder(ORG) for roll failure prevention. In this study, a computer roll wear prediction model under real process working condition is developed and evaluated with hot rolling pass schedule. The method of building wear calculation functions for center portion abrasion and marginal abrasion respectively was used to develop a work roll wear prediction mathematical model. The three type rolling schedule are evaluated by wear prediction model. The optimum roll grinding methods is suggested for schedule tree rolling technique.

• Journal of the Korea Furniture Society
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• v.22 no.3
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• pp.239-243
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• 2011

In this study, the coating properties and surface performance of exotic cherry wood (Prunus serotina) were estimated, reviewing color difference, hardness and abrasion resistibility in order to evaluate probability as construction interior members such as wall and floor. The reduction effect of color difference was represented in the order of water soluble color stain, water soluble transparent stain, and non-coated lumber. However, the tendency of distinct difference according to wood grain pattern was not found. The wavy grain lumber showed better properties in hardness and resistance to abrasion than quarter grain. In conclusion, it was supposed that the application of wavy grain lumber in wall and floor as interior materials would be acceptable in practicality.

• Restorative Dentistry and Endodontics
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• v.26 no.2
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• pp.171-179
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• 2001

The purpose of this study was to evaluate the shear bond strength of compomers according to dentin surface treatment. Two materials of compomer were devided into six groups. The compomer used in this study were Dyract AP(D) and F2000(F), Group 1 (DN) and 4(FN) were treated according to manufacturers instructions as control groups. Group 2(DE) and 5(FE) were treated with 37％ phosphoric acid and group 3(DA) and 6(FA) were treated with air abrasion unit (80 psi, 50 m aluminum oxide particles) respectively as experimental groups. After dentin surface treatment, compomers were bonded. Completed samples were stored in 100％ humidity. 37C during 7 days, and then, the shear bond strength of specimens were evaluated. The results were as follows: 1. In the case of Dyract AP, the shear bond strength was showed the highest value of 9.10 MPa in dentin surface treatment with air abrasion unit. but there were no significant differences to the other groups. 2. In the case of F2000. the shear bond strength was showed the highest value of 13.51MPa and there were significant differences to the other groups(p<0.05). 3. The shear bond strength of F2000 was higher than Dyract AP in each dentin surface treatment. and in the case of etching and air abrasion. there were significant differences(p<0.05). 4. As a result of observation of SEM. the most of fracture pattern was adhesive failure in group 1(DN), 2(DE) and 4(FN), and cohesive failure in group 3(DA), S(FE) and 6(FA).

• Tribology and Lubricants
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• v.39 no.6
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• pp.250-255
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• 2023

This study applies various surface patterns to minimize material loss in construction equipment that is subject to severe wear due to sand, such as the wear-resistant steel plates of dump trucks or the teeth of excavators. The relationship between surface morphology and wear behavior is investigated using PLA+ polymer to observe the effect of the surface pattern. Five types of samples - smooth, concave, convex, wavy concave, and wavy convex designs - are created using a 3D printer. A wear experiment is conducted for a duration of 3 h using 6.5 kg of abrasive particles. The mass loss of the samples after the experiment is measured to assess the extent of wear. Additionally, the surface morphology of the samples before and after the experiment is analyzed using SEM and confocal microscopy. The study results reveal that the smooth design exhibits the highest wear loss, whereas the concave and wavy concave designs show relatively lower wear loss. The convex and wavy convex designs exhibit varying contact areas with the abrasive particles depending on the surface pattern, resulting in different levels of wear. Furthermore, a comparison between the experimental results and DEM simulations confirms the observed wear trends. This study reveals the relationship between wear damage according to surface pattern shape and is expected to be of substantial help in the analysis of wear and tear on agricultural and heavy equipment.