• Transactions of the Korean Society of Machine Tool Engineers
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• v.11 no.4
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• pp.26-33
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• 2002

One characteristic of Fine-Blanking is that the size and the direction of stress and strain are very complex in the plastic flow according to the condition of blanking. Especially, they are affected by the clearance of punch and die, by the force of blanking holder and by the force of counter punch. The purpose of this research is to how the deformation behavior in shear zone more clearly, based on Green & Cauch's large deformation theory. The deformation behavior and cracks were investigated in each step of shear, according to punch penetration increase, the use of V-indenter ring and the hardness of materials. This research found that the transforming behavior was the same as pure discretion and the cracks could be prevented when hardness is low.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.05a
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• pp.127-130
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• 2004

In the recent years, lightweight components fabricated with aluminum alloys have been applied into building the automobiles. Among the several competing fabrication methods, hot forging is taken as the most reliable technique to produce suspension parts such as control arms. Generally, Al forging products have been used widely for the aircraft building with the extruded stock as a starting material. For the economical base, however, the cast stocks turn to be as the forging stocks recently after a continuously casting technique was developed to produce quite a uniform microstructure enough to use for the forging process. Even more, there is a tendency to omit the homogenization step before forging, which is considered to be an indispensable process for all kinds of Al alloy, In the present study, a series of compression test was carried out to find out how the cast structure and the following heat treatments influence the deformation behavior, that is, forging characteristic.

• Journal of KSNVE
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• v.9 no.3
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• pp.472-476
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• 1999

The effect of static preload on the dynamic properties of rubber materials is rather important, especially when good isolation characteristics are required at high frequencies. However, there are still few papers for dynamic characteristics of compressed rubber components. It was demonstrated in reference (4) that for bonded rubber material of a cylindrical shape, a simplified theory equation between linear dynamic and nonlinear static behavior of rubber material was useful to predict their combined effects. This paper presents the second part of the study. It is confirmed that for the compressed rubber material, the stress can be factored into a function of frequency and a function of strain(stretch). The finite element methodis applied to analyze non-linear large deformation of rubber material and its results are compared with those of a simplified theory equation. The predicted dynamic material properties based on non-linear static finite element analyses have a good agreement of experimental results and those based on simplified theory equation.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.7
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• pp.659-666
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• 2012

A nonlinear dynamic model for the shaft-disk-blade unit is developed in this study. In this regard, the rotating flexible blade, with a pre-twist angle, attached to a rigid disk driven by a shaft which is flexible in torsion is developed. The rotor-blade coupled model is derived using Lagrange equation in conjunction with the assumed mode method to discretize the blade deformation. The equations of motion are analyzed based on the small deformation theory for the blade and shaft torsional deformation to obtain the system natural frequencies for various system parameters.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.388-390
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• 1997

We describe the characteristic of LVI(Low-voltage Impulse) test system and methods to detect the deformation of windings in the power transformers. Any winding deformation will result in a change of capacitance between winding parts and possibly some change in the winding inductance. These changes will then result in a change in the responce to the applied pulse in both the magnitude and period of the resulting oscillations. A results of measured differential method in stead of typical method, the sensitivity is greatly improved by the use of differential methods where the pulse is applied to two identical windings and the response measured with a differential amplifier.

• Proceedings of the KIEE Conference
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• 1997.07e
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• pp.1737-1739
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• 1997

We describe the characteristic of LVI test system and methods to detect the deformation of windings in the power transformers. As the front rise time of recurrent-surge generator pulse less than 1000ns and the peak value of pulse is about 500V, we have the good results of detecting winding deformation in the LVI test of transformer. And we discuss the application of LVI test method and the condition of RSG pulse through results of in one and three pole transformers under Lab. tests.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.484-491
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• 2008

The purpose of this study is to compare the cementation effect on cone resistance and DMT indices and to evaluate the deformation characteristic of cemented sand using cone resistance and dilatometer modulus. Specimens of various relative densities with three different cementation levels are prepared in a large calibration chamber under different vertical stress levels. Test result shows that the cone resistance and dilatometer modulus underestimate the deformation modulus of cemented sand, since in situ penetration tests such as CPT and DMT damage the cementation bonds during penetration. By regression analysis, the constrained modulus of cemented sand is related with the cone resistance and the dilatometer modulus.

• Journal of Korean Association for Spatial Structures
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• v.24 no.1
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• pp.37-45
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• 2024

Steel plate shear walls (SPSWs) have been recognized as an effective seismic-force resisting systems due to their excellent strength and stiffness characteristics. The infill steel plate in a SPSW is constrained by a boundary frame consisting of vertical and horizontal structural members. The main purpose of this study was to investigate deformation modes and hysteretic characteristics of steel plate shear walls (SPSWs) to consider the effects of their aspect ratios and width-to-thicness ratios. The finite element model (FEM) was establish in order to simulate cyclic responses of SPSWs which have the two-side clamped boundary condition and made of conventional steel grade. The stress distribution obtained from the FEA results demonstrated that the principal stresses on steel plate with large thickness-to-width ratio were more uniformly distributed along its horizontal cross section due to the formation of multiple struts.

• Journal of Korean Society of Steel Construction
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• v.13 no.6
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• pp.693-702
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• 2001

Ductility pipes, like corrugated steel structures, are expected to reduce its deformation when they are arranged in a row. Verifying this assumption can help make economic designs possible. Though checking the deformation of ductility pipe structures, like corrugated steel structure, decreasing deformation was found when the pipes are arranged in a row. In this way, arranging a corrugated steel structures in a row shows decreased deformation compared to corrugated steel pipes arranged in a single structure because the bedding effect restrains deformation. The deformation rates of reduction are proportionate to the diameter of the corrugated steel structure.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.291-292
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• 2012