• Journal of the Korean Society of Propulsion Engineers
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• v.16 no.1
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• pp.79-85
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• 2012

This study investigates mainly on the technical development trend through the published papers, such as asymmetric metal spinning, metal spinning in heat treatment conditions and free mandrel spinning. Although the classical spinning, so called conventional, shear, tube spinning, uses the axisymmetric shaped mandrel(which is same inner shape of the final product), in new technologies the mandrel can be asymmetric one, spinning can be done without mandrel and also spinning is done with heat treatment together.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.241-244
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• 2010

This paper investigates mainly the new free mandrel technology of the metal spinning. Although the classical spinning, so called conventional, shear, tube spinning, uses the axisymmetric shaped mandrel(which is same inner shape of the final product), new technology does not use it.

• Transactions of Materials Processing
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• v.14 no.9 s.81
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• pp.764-771
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• 2005

This study is related with the development of CNC spinning machine and the axisymmetric conventional spinning such as drum type and conical type steel shells. The CNC spinning machine is constructed with heavy duty frame and the hydraulic servo system is applied in order to give the exactness of motion control. The experiment has been carried out considering feeding velocity, mandrel shape, and the corner radius of mandrel and forming rollers. As a result of experiment, the limiting spinning ratio and thickness strain distribution are obtained and it can be seen that the spinnability is dominant to the feeding velocity and corner radius of forming roller. This research can contribute to the development of axisymmetric mechanical part which is applicable to automotive and aerospace industry.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.79-81
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• 2000

Outdoor insulation of overhead distribution lines with wood, concrete and steel pole has been safety under various environmental conditions including contamination, moisture condensation, rain and lightning overvoltages. In this paper introduce to FRP technology of the power distribution single pole. FRP pole has been used very much as high strength material for insulators because of its high strength and good insulation properties. In addition, FRP pole was made by filament winding method. In a filament winding process, a band of continuous resin-impregnated rovings or monofilaments is wrapped around a rotating mandrel and cured to produce axisymmetric hollow parts.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.265-271
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• 2011

This paper investigates mainly on the technical development trend such as asymmetric technology and the metal spinning in heat treatment conditions. Although the classical spinning, so called conventional, shear, tube spinning, uses the axisymmetric shaped mandrel(which is same inner shape of the final product), new technology does not use it. and also spinning can be done with free mandrel.

• Transactions of Materials Processing
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• v.7 no.1
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• pp.72-80
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• 1998

This study is concerned with the thermo-biscoplastic finite element analysis of hot tube extrusion through square dies with a mandrel. The problem is treated as a non-steady state and the ALE description is used due to abruptly turning flow at the die aperture. Since the contact heat transfer coefficient and the friction factor are required in the analysis experiments are also carried out to determine the values, In order to apply ceramics to an extrusion die the study is focussed on under-standing the characteristics of the process. The simulated results provide the useful informations such as metal flow temperature distribution stress state etc. The elastic analysis of the dies is carried out to obtain the stress state of the ceramic dies.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.470-474
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• 2000

Cold expansion of fastener holes is a mechanical process widely used in the aerospace industry. This treatment leads to an improvement of fatigue behavior due to the developed compressive residual stresses on the hole surface. The residual stress profile depends on the parameters of cold expansion, which are, expanding rate, inserting direction of mandrel, material properties etc. and the method to confirm this profile is only measurement by X-ray diffractometer. Despite its importance to aerospace industries, little attention has been devoted to the accurate modelling of the process. In this paper, Two-dimensional axisymmetric finite element simulations have been conducted for the cold expansion in an aluminium plate in order to predict the magnitude and distribution of the residual stress and plastic deformation. Maximum compressive residual stress could be increase about 7 percent using the 2-step cold expansion method.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.882-886
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• 1996

The use of ceramics for extrusion dies is limited since the modification of die design is difficult. In order to successfully apply the ceramic dies to extrusion dies, a better understanding of the process should be preceded. This study focuses on understanding the characteristics of the process. In the present study, a hot extrusion of tube with a mandrel is analyzed by ALE finite element method. In order to obtain the stress state of ceraminc dies, the elastic analysis of dies is also carried out.