The quality and quantity of heat treatment in mold processing can vary depending on the skill level of the equipment operator. Therefore, study on ways to overcome these disadvantages are essential. This study aimed to increase the antiwear properties of molds through high-frequency induction heat treatment and laser heat treatment processes. The heat treatment was applied to the surfaces of molds used in car body production using an articulated robot, to achieve long-term use and quality maintenance. Additionally, an articulated robot system based on redundant degrees of freedom suitable for mold heat treatment processes was designed, and its operational efficiency was verified through virtual environment simulations. Furthermore, heat treatment was validated through on-site testing of the robot system. Its effects were analyzed according to mold materials and shape conditions, ultimately deriving the optimal robot heat treatment conditions. Finally, off-line programming (OLP) in virtual processes was proposed to minimize robot setup time and maximize production efficiency. The conditions for articulated robot automated heat treatment obtained in this study can be preapplied in simulation environments when generating heat treatment robot programs based on OLP. They can be utilized for optimizing the quality of mold heat treatment in car body production.

In this study, thin-shell surface observation, storage capability test, and micro-compressive test were performed for self-healing microcapsules using a field emission scanning electron microscope (FE-SEM) and a micro-compressive testing machine. A microcapsule having a melamine-urea-formaldehyde thin-shell and a microcapsule having a melamine-urea-formaldehyde thin-shell reinforced with carbon nanotubes were used. Two carbon nanotube contents were considered: 0.17 wt% and 0.50 wt%. Thin-wall shell state was relatively smooth when microcapsules were not reinforced with carbon nanotubes. It was uneven when microcapsules were reinforced with carbon nanotubes. Prepared microcapsules showed little decreases of weights even when the exposure time was increased regardless of whether they were reinforced with carbon nanotubes. Thus, their storage capability was good. When carbon nanotube content was the same, the fracture load was almost constant without being affected by the diameter of the microcapsule. However, fracture displacement increased with increasing diameter of the microcapsule. When diameters of microcapsules were similar, fracture load and fracture displacement increased when carbon nanotube content increased. It was found that self-healing microcapsules had good storage capability and mechanical properties. Thus, they could be applied to repair damage to composite materials if thin-shell formation mechanism for adding carbon nanotubes is supplemented.

In this study, the deformation of a large industrial door subjected to wind load was investigated through computational fluid dynamic and structural analyses. The model for the structural analysis was simplified by considering the PVC curtain and wind bar in the shape of the actual door. The pressure distribution acting on the front of the door was obtained from computational fluid dynamic analysis and the deformation of the door was obtained from structural analysis. According to the results, the pressure distribution was not uniform on the front of the door and varied depending on the location. The distribution of the deflection in the wind bar was obtained and it was found that the position of the maximum deformation occurred slightly above the center of the door. Finally, the deformation of the door could be predicted by analyzing the deflections of the wind bar subjected to different wind speeds through regression analysis.

In this study, the mechanical joint performance of the V-Insert clamp applied to automobile exhaust pipes was evaluated through the experimental investigation of its axial load capacity. The axial load of the V-Insert clamp was also determined by using theoretical equations presented by Shoghi and compared with the experimental results. As results of the theoretical prediction, the axial load of the V-Insert clamp tended to increase along with smaller angle of the V-Insert segment and the lower friction coefficient between the V-Insert segment and exhaust pipes. The experimental results under tightening effects were similar to the theoretical results and the axial load of the V-Insert clamp presented maximum values in the range of all torques at distance of 2㎜ between each exhaust pipes. The experimental results under loading effects were similar to the theoretical results in the range of lower torques but deviated from the theoretical results in the range of higher torques. These results would be beneficial to improve the joint and sealing performance of the V-Insert clamp.