• Proceedings of the KSME Conference
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• 2000.11a
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• pp.688-692
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• 2000

This study proposed design parameters of opening spring of circuit breaker that cut off the over-current in order to protect the electric device about opening speed using the energy method. We simulated the opening kinetic energy, the potential energy of opening spring and the design parameters of opening spring with respect to opening speed of VCB (Vacuum Circuit Breaker)'s moving contactor which has 24kV 25kA break capacity. From the result of simulation the initial tensional force and the final tensional force of the opening spring chose 107kgf and 282kgf respectively. Through the dynamic analysis using ADAMS, We verified that the opening speed of moving contactor satisfied break capacity of VCB and analyzed opening dynamic characteristics of VCB such as the opening displacement, the opening velocity and the opening acceleration of moving contactor in time domain.

• Journal of the Korean Society of Costume
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• v.58 no.8
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• pp.120-136
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• 2008

This study examined sewing methods used to reinforce the opening of clothes of the Joseon period. Through the analysis of a total of 117 clothing items of the Joseon period, the following results were obtained. 1. Most costumes of the Joseon period had the opening. The purpose of the opening was to allow one to put on and take off a costume, act comfortably, and turn a costume Inside out. The opening was located on the Side, Conte. Back, fgwi(Side opening of pants), Wristband, Armhole, and Godae(the bark part of the collar). 2. As the opening tended to get easily worn out, it was often reinforced. The 1911owing three methods were used to reinforce the opening of clothing items of the Joseon period: a method to attach a cloth such as Dang, Binding, and Badae; a method using a variety of knots; and a method by sewing stitches such as a sort of cross stitch called Satteugi, Prick stitch, and Loop. 3. The most frequently used reinforcing method was the one that used a knot(34 items), followed by the one by sewing Satteugi(27 items), and the one using Dang(25items). The most frequently detected location of the opening was Side(59 items), followed by Agui(37 items), Wristband(19 items), and Center Back(13 items). 4. The reinforced opening made a costume more endurable and elastic, decorative and neat.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.8
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• pp.1493-1502
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• 1992

The purpose of this study is to identify the effects of loading variables on fatigue crack opening behavior, using structural steel SS41. To use various stress ratios, three kinds of the methods varying stress ratio were used; .DELTA.P const., P$_{max}$ const., and P$_{min}$ const.. To measure the opening load, the direct measuring method which measures the distance between two micro indentations 20 .mu.m behind crack tip and the elastic compliance method were used. As the results of present study, the following conclusions are obtained. First, using the direct measuring method, it was possible to measure the COD at any location behind crack tip. Second, as measuring point becomes farther from crack tip, opening load becomes smaller. Third, the acceleration of da/dN near notch is due to crack opening behavior. Finally, opening ratio is a function of not only R, but .DELTA.K.K.K.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.4
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• pp.908-917
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• 1995

The constant .DELTA.K fatigue tests are performed in SS41 and its weldments to investigate crack opening behavior and fatigue crack propagation behavior at each parts of weldment and its boundary layer. The weldments were annealed after welding for the purpose of relieving residual stress. Every weldments has notch at weld metal zone, and fatigue crack propagates from weld metal zone to vase metal zone perpendicular to weld line. The Laser ISDG method is used in order to determine the crack opening ratio, this method is more precise than indirect measurement method, and faster and easier than other direct measurement method.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.202-207
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• 2004

An elastic-plastic finite element analysis of fatigue crack closure is performed for plane strain conditions. The stabilization behavior of crack opening level and the effect of mesh size on the crack opening stress are investigated. In order to obtain a stabilized crack opening level for plane strain conditions, the crack must be advanced through approximately four times the initial monotonic plastic zone. The crack opening load tends to increase with the decrease of mesh size. The mesh size nearly equal to the theoretical plane strain cyclic plastic zone size may provide reasonable numerical results comparable with experimental crack opening data. The crack opening behavior is influenced by the crack growth increment and discontinuous opening behavior is observed. A procedure to predict the most appropriate mesh size for different stress ratio is suggested. Crack opening loads predicted by the FE analysis based on the procedure suggested resulted in good agreement with experimental ones within the error of 5 %. Effect of the distance behind the crack tip on the crack opening load determined by the ASTM compliance offset method based on the load-displacement relation and by the rotational offset method based on the load-differential displacement relation is investigated. Optimal gage location and method to determine the crack opening load is suggested.

• Journal of the Korean Society of Safety
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• v.16 no.2
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• pp.7-12
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• 2001

The finite volume method was utilized for computation of convection heat transfer in a two-dimensional enclosure with an inflow opening and an outflow opening. The objective of this study is to investigate temperature distribution on ceiling for different locations and sizes of the outflow opening. The inflow opening was set to be H$_{i}$=0 and U=50. The results fur different sizes of the opening H$_{0}$=0.1, 0.2, 0.3, and 0.4 shooed similar flow patterns and temperature distribution. Location of the outflow opening, however, influenced significantly on the temperature distribution on the ceiling.ing.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.9 s.180
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• pp.2283-2291
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• 2000

The neural network method is applied to automatically measure the crack opening load under random loading. The crack opening results obtained are compared with the visual measured results. Fatigue crack growth under random loading is predicted using the crack opening data measured by the neural network method, and the prediction results are compared with experimental ones. It is found that the neural network method can be successfully applied to consistently measure the crack opening load under random loading and also gives some results different from the results by visual measurement.

• Journal of Mechanical Science and Technology
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• v.18 no.11
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• pp.1989-1995
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• 2004

Finite element analysis(FEA) is the most popular numerical method to simulate plasticity-induced fatigue crack closure and can predict fatigue crack closure behavior. Finite element analysis under plane stress state using 4-node isoparametric elements is performed to investigate the detailed closure behavior of fatigue cracks and the numerical results are compared with experimental results. The mesh of constant size elements on the crack surface can not correctly predict the opening level for fatigue crack as shown in the previous works. The crack opening behavior for the size mesh with a linear change shows almost flat stress level after a crack tip has passed by the monotonic plastic zone. The prediction of crack opening level presents a good agreement with published experimental data regardless of stress ratios, which are using the mesh of the elements that are in proportion to the reversed plastic zone size considering the opening stress intensity factors. Numerical interpolation results of finite element analysis can precisely predict the crack opening level. This method shows a good agreement with the experimental data regardless of the stress ratios and kinds of materials.

• Nuclear Engineering and Technology
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• v.29 no.3
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• pp.251-259
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• 1997

This paper describes experimental investigations of helium-air exchange flows through partitioned opening and too-opening. Such exchange flows may occur following rupture accident of stand pipe in high temperature engineering test reactor. A test vessel with the too types of small opening on top of test cylinder is used for experiments. An estimation method of mass increment is developed to measure the exchange now rate. Upward flow of the helium and downward flow of the air in partitioned opening system interact out of entrance and exit of the opening. Therefore, an experiment with too-opening system is made to investigate effect of the fluids interaction of partitioned opening system. As a result of comparison of the exchange flow rates between too types of the opening system, it is demonstrated that the exchange flow rate of the two-opening system is larger than that of the partitioned opening system because of absence of the effect of fluids interaction.

• Journal of Welding and Joining
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• v.21 no.6
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• pp.77-83
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• 2003

The finite element analysis was performed for the cracks existing in residual stress fields in order to investigate the effects of configuration of residual stress distribution to the fatigue crack opening behaviour. And the variation of stress distributions adjacent to the crack caused by uploading was examined. The finite element model with contact elements for the crack plane and plane stress elements for the base material and the analytical method based on the superposition principle to estimate crack opening behaviour and the stress distribution adjacent to the crack subjected to uploading were used. The results of the analysis showed that crack opening behaviors and variations of stress distribution caused by uploading were changed depending on the configuration of residual stress distribution. When the crack existed in the region of compressive residual stress and the configuration of compressive residual stress distribution were inclined, a partial crack opening just behind of a crack tip occurred during uploading. Based on the above results, it was clarified that the crack opening behaviour in the residual stress field could be predicted accurately by the finite element analysis using these analytical method and model.