Papers by Author: Myung Seok Ko

Abstract: Importance on the detection of corrosion-related defect is undeniable from the fact that it can prevent significant economic loss and enhanced safety in mechanical equipments, pipes, ships, bridges, and other applications. Conventionally researched measurement methods for defect and thinning from corrosion are acoustic emission, EMAT using ultrasound, laser induced ultrasound, etc. However, these non-destructive testing methods have the shortcoming of accessibility to on-site. For instance, EMAT should be close to several millimeters to generate magnetic field in structure. For laser application, it can be applied to remote non-destructive testing, but some defect might not be possible to be detected by the surface condition of structure. In this study, infrared thermography camera is utilized to determine the degree of corrosion on paint-coated metal. In addition, fundamental researches to develop corrosion detection system for on-site metallic structure are conducted to provide the applicability of IR camera and possibility of thermal analysis method.

Abstract: Extrusion screw that is used on market of present extrusion molding catapult is divided by single-axle extrusion screw and multi-axles extrusion screw. Simulation technique of screw that is used in extrusion molding has become so far various. Consist of that analyze third dimension model and that analyze two-dimension model but most Analysis that display dynamic characteristic of screw inside of heat and flow in detail was not until present. Transfer of polymer site that typical single-axle extrusion screw that is analysis target of this treatise is mixed in most melting state is good, but has some controversial points. First melting transfer of balance that is not done difficult. Second melting causes effect that weaken mechanical special quality of screw by power excessive last month if heighten the screw speed to increase amount of done balance. Third Screw dynamic characteristic symptoms by thermal expansion that happen in screw of heater is fallen.