• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.1
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• pp.100-107
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• 2020

As demand for high value-added products with hard materials increases, the line center is used for producing high value-added products in many industries such as aerospace, automobile fields. The line center is a key device for smart factory automation that can improve the production efficiency and the productivity. Therefore, the development of a mill-turn line center is necessary to produce high value-added products with complex shapes flexibly. In the mill-turn process, a milling process and a turning process are combined. In particular, the turning process needs to increase the rigidity of the spindle. The purpose of this study is to analyze the thermal-structural stability through thermo-structural coupled analysis for a mill-turn spindle with a curvic coupling. The maximum temperature and thermal stability of the spindle were analyzed by thermal distribution. In addition, the thermal deformation and thermal-structural stability of the spindle were analyzed through thermo-structural coupled analysis.

• Tribology and Lubricants
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• v.26 no.1
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• pp.31-36
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• 2010

The brake system is an important part of the automobile safety system. The disc brake system is divided into two parts: a rotating axi-symmetrical disc, and the stationary pads. The frictional heat, which is generated on the interface of the disc and pads, can cause high temperatures during the braking process. The frictional heat source (the pads) is moving on the disc and the location is time-dependent. Our study applies a moving heat source, which is defined by the time and space variable on the frictional surface, in order to simulate the frictional heat behavior accurately during the braking process. The object of the present work is the determination of the temperature distribution and thermal stress in the solid disc by non-axisymmetric 3D modeling for repeated braking.

• Elastomers and Composites
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• v.45 no.1
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• pp.12-16
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• 2010

In this work, the effect of hydrophobic treated silica on the water absorption, thermal stabilities, and mechanical properties of the epoxy nanocomposites were investigated as a function of the silica content. As filler, fumed silica treated by dimethyldichlorosilane was used. It was found that the silica was well dispersed in the epoxy resins by the melt-mixing method with the addition of a silane coupling agent. The water absorption of the nanocomposites decreased with an increase of the silica content due to the effect of hydrophobic treated silica. The thermal properties, such as thermal degradation temperature, glass transition temperature ($T_g$), and coefficient of thermal expansion (CTE), of the nanocomposites were improved by the addition of silica. Furthermore, the mechanical properties of the nanocomposites, that is, the tensile strength and modulus, were enhanced with increasing silica content. This was attributed to the physically strong interaction between silica and epoxy resins.