• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.5
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• pp.837-846
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• 1989

Belt tension distribution for an abrasive blet grinding was investigated analytically and experimentally for (1) slack side and (2) tight side blet grinding. Classical Eytelwein equation was used to predict the belt tension distribution with dividing contact angles into (1) inactive and (2) active angles. General friction theory was modified based on the friction force between the belt and the support in the grinding contact area that was obtained by experiments. It was found that analytical results were in good agreement with the experimental results. Also, the tight side belt grinding was recommended since it could carry out more grinding load than that of slack side belt grinding.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.3
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• pp.457-465
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• 1988

The inside contact characteristics in abrasive belt drives were investigated analytically and experimentally for (1) driver pulley contact wheel and (2) driven pulley contact wheel. The concentrated contact forces in the grinding zone divided the entire belt-pulley contact are by three distinct areas and the tangential friction forces in the active areas caused the normal forces to change, which resulted in the different belt force distribution compared with those of the ordinary flat belt drives. The experimental results for the normal pressure (belt tension) distribution were in good agreement with the theoretical results.

• Special Issue of the Society of Naval Architects of Korea
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• 2013.12a
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• pp.66-72
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• 2013

The demand for an ice class ship is rising expected to rise according to the increase of energy consumption and the opening of arctic sea routes. Ice class ship should be designed to cope with the severe environmental conditions of arctic sea such as a high mechanical impact and abrasion damage, caused by pack ice, ice bergs and low temperature. The ice class ship hulls are coated with an anti-abrasion and low friction coating such as a solvent free epoxy or high solid-volume epoxy. These coatings require two-component heating pump and a high grade surface preparation. In this study, the coating performances for the arctic vessels, such as puncture absorbed energy, abrasive wear loss, friction coefficients and impact absorbed energy were evaluated. Based on this study, a proper coating performance specification for the arctic vessels was proposed and coating selection guideline in terms of coating performance and workability was also established.

• The Journal of Engineering Geology
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• v.15 no.2 s.42
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• pp.169-184
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• 2005

Unagsan and Sogrisan granites are widely distributed in the northern Gyeonggi massif and middle Ogcheon belt, respectively, and they show different petrologic characteristics as follows. The former has compact textures and light grey colors, and the latter has spotted miarolitic textures and pink colors. Most of the samples selected for tests are fresh and coarse-grained. And bored core samples were prepared so that they are vertical to the rift plane. The results of modal analysis show that Unagsan granite has significantly higher quartz and plagioclase contents (Qz+Pl) than Sogrisan granite. In contrast, alkali feldspar content (Af) of Sogrisan granite is much higher than that of Unagsan granite. Therefore, it is believed that the light grey colors of Unagsan granite are due to relatively high Qz+Pl, and the pink colors of Sogrisan granite are caused by higher Af. Fractures in Sogrisan granite have strongly perpendicular strike patterns and more dip values close to vertical compared with the fractures in Unagsan granite. Results of the fracture pattern analysis suggest that the Sogrisan granite has better potential to produce dimension stones than the Unagsan granite. However, miarolitic textures often found in the Sogrisan granite may be one of the factors reducing the granite quality. The Unagsan and Sogrisan granites have similar specific gravity values of 2.60 and 2.57, respectively. Absorption ratios and porosity values of Sogrisan granite are higher than those of Unagsan granite, and they shows linearly positive correlations. Compressive and tensile strengths of the Unagsan granite are generally higher than those of Sogrisan granite. These differences and variation trends found in physical properties of Unagsan and Sogrisan granite can be explained by the differences in the textures of Unagsan and Sogrisan granites, namely compact and miarolitic textures respectively. For Unagsan granite, compressive and tensile strengths are negatively correlated with porosity but for Sogrisan granite no specific correlations are found. This is probably due to the irregular dispersion patterns of miarolitic textures formed during the later stages of magmatic processes. Contrary to the trends found in absorption ratios, both granites have similar values of abrasive hardness, which can be explained by higher Qz+Af of the Sogrisan granite than those of the Unagsan granite and that quartz and alkali feldspar have relatively larger hardness values. For Sogrisan granite, compressive strength shows slightly positive correlations with Qz+Af+Pl and negative correlations with biotite and accessory mineral contents (Bt+Ac).