• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.33 no.4
• /
• pp.296-309
• /
• 2009

Thick-walled cylinder with high pressure have had wide application in the armament industry. In the thick-walled cylinder, fatigue crack is generated at inner radius and developed toward the outer radius. To prevent generation of fatigue crack, the autofrettage process had been used. The compressive residual stress induced by the autofrettage process extends loading pressure and fatigue life of the thick-walled cylinder. In this study, the residual stress of single and compound cylinder by the autofrettage process was evaluated. The analytical compressive residual stress of single cylinder was good agreement with experimental result at inner radius. The analysis on the residual stress of compound cylinder was conducted. The compressive residual stress at inner radius was increased with the overstrain level. And fatigue life of the compound cylinder with initial crack was evaluated. The considered initial crack shape was straight and semi-elliptical. The fatigue life was extended with the overstrain level. The fatigue life of the compound cylinder with semi-elliptical crack was longer than straight crack. The suitable way to extend fatigue life of the compound cylinder was proposed.

• Journal of Drive and Control
• /
• v.10 no.2
• /
• pp.13-22
• /
• 2013

It is difficult to analytically derive a volumetric displacement formula of gerotor hydraulic pump/motor because geometric shape of rotors is complicated. An analytical method about the volumetric displacement is proposed in this work, which is relatively easy and based upon two physical concepts. The first one is energy conservation between hydraulic energy of the pump/motor and mechanical input/output energy. The second concept is torque equilibrium with respect to inner and outer rotors. The formula about the volumetric displacement is derived for the common case of inner and outer rotors rotate with respect to fixed axes. The formula is verified by comparing another analytical displacement formula, and it is numerically verified by comparing numerical results, which is calculated for geometric specification of a motor. The numerical displacement is calculated through CAD software program and MATLAB program. The proposed analytical formula can be utilized in analysis and design of hydraulic gerotor motors.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.19 no.6
• /
• pp.760-765
• /
• 2009

Since the features in object-images such as color and shape cannot clearly express the characteristic of objects, those features lead to vagueness of object-image recognition. Recently there have been studied on object-image recognition based on knowledge base in order to reduce the vagueness. However, because images are represented by numerical information but knowledge bases are represented by conceptual information, combining two kinds of information is difficult. In this paper, we compose knowledge base by using ontology to reduce the gap between the two kinds of information, and propose a method for object-image recognition to reduce the vagueness by using information on inner-object. Moreover, we confirm the usefulness of the proposed method through the experiments on object-image recognition in fruit domain.

• Journal of the Korean Society of Costume
• /
• v.60 no.4
• /
• pp.58-75
• /
• 2010

The purpose of this study is to investigate the characteristics of fur and leather clothes of minority races of China in Northeas and Inner Mongolia. To examine their characteristics, the clothes and ornaments were classified into four types: headwear, clothes, footwear, and accessories. First, headwear was divided into animal head-shaped, petal-shaped, round-shaped, and cone-shaped head wear. Among them, the animal head-shaped headwear was made by making the best use of the shape of animal's head and it was used as the best disguising method when hunting. Second, clothes were composed of upper garments and lower garments. For the upper garments, Po and Jeogori were worn and pants were worn for the lower garments. The clothes were decorated with lining, applique, or top-stitching on the outer collar, neck circumference, and the edge of sleeves and pants. Third, for the footwear, high boots of leather were developed to meet the needs for a convenient life in the plains. In some areas, fur shoes and leather shoes were also used. Finally, accessories included bags and gloves. Bags were usually decorated with fur on the outside or with a fringe or applique of tanned leather. Gloves were lavishly decorated with embroideries and partly with fur or leather.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.18 no.6
• /
• pp.88-95
• /
• 2014

Spinning process to inner wall has been applied for reducing the weight of regenerative cooling chamber of liquid propellent rocket engine. The fractures of the blanks of cylinder part and nozzle throat part have been observed during spinning processes. In order to overcome the problem, the mandrel and the blank shape have been modified, and the inner wall was successfully manufactured through the modifications. The manufactured spinning prototype of nozzle throat part was successfully bulged without cracking and necking, and it was confirmed to secure sufficient formability necessary for fabricating thrust chamber.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.15 no.2
• /
• pp.46-50
• /
• 2016

When rotating the clutch drum in the power take-off (PTO) gear box of an armored recovery vehicle, lots of inner oil is drained through the adapter by centrifugal force. Therefore, a lack of lubrication is caused by inner oil loss, and the bearing is damaged by overheating. This study, therefore, aims to design an oil-controlling adapter by using shape alteration to prevent oil loss. Both the original and improved adapters were tested at 1,800rpm by using an operational test machine. When applying the original adapter to the gear box, the bearing was damaged by overheating, which was caused by the lack of lubrication. When applying the improved oil-controlling adapter, on the other hand, it prevented the loss of inner oil. Applying the improved adapter is expected to prevent the overheating caused by lack of lubrication.

• Journal of the Korean Society of Costume
• /
• v.64 no.4
• /
• pp.106-117
• /
• 2014

The purpose of this study is to provide basic information for the development of well-fitting and comfortable brassieres for women in their 30s, based on the classification of breast shapes by utilizing 3D body measurement data of women in the age group. The result of processing the measurements from the 3D body scan data through RapidForm 2006 shows that while the vertical body measurements decrease, the horizontal measurements, which indicates the degree of obesity, increase proportionally with age. Also, the relevant measurements for upper breasts increase proportionally with age, while the measurements for lower part of the breasts decrease as the degree of sagging increases. Four composition factors of the breasts were identified through the factor analysis: Factor 1 is the level of volume in the breasts and the surrounding area; Factor 2 is the position of nipples and the shape of upper part of breasts; Factor 3 is the position and vertical length of the breasts; Factor 4 is the shape of lower part of breasts; and Factor 5 is the shape of inner part of breasts and degree of width between both breasts. The breasts have been categorized into three distinctive shapes: Breast Shape 1, Breast Shape 2 and Breast Shape 3. According to the results of the cluster analysis, the largest percentage (36.68%) of women in their 30s falls into the category of Breast Shape 2 with small volume and flat upper breasts, followed by Breast Shape 1 (32.66%) with large volume in the upper and lower parts of breasts, and large side to side area, and Breast Shape 3 (30.65%) with average volume and width between breasts.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2007.05a
• /
• pp.352-356
• /
• 2007

In this study, a rigid-plastic finite element method is applied to simulating a ring rolling process of the inner race cage of a constant velocity joint for the passengers' cars. The ring rolling process is mathematically modeled by several assumptions. The defect formation at the side ends is predicted in detail. The predictions are compared with the experiments and a good agreement is observed in terms of deformed shape.

• Journal of Institute of Control, Robotics and Systems
• /
• v.9 no.10
• /
• pp.822-831
• /
• 2003

A computer-vision based pipe-inspection algorithm is developed. The algorithm uses the modified Hough transformation and a line-scanning approach to identify the edge line and the radius of the pipe image, from which the eccentricity and dimension of the pipe-end is calculated. Line and circle detection was performed using Laplace operator with input image, which are acquired from the front and side cameras. In order to minimize the memory usage and the processing time, a clustering method with the modified Hough transformation is introduced for line detection. The dimension of inner and outer radius of pipe is calculated by the proposed line-scanning method. The method scans several lines along the X and Y axes, calculating the eccentricity of inner and outer circle, by which pipes with wrong end-shape can be classified and removed.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.4 no.6
• /
• pp.27-38
• /
• 1996

A two-dimensional FEM program, which considers bending effects in the membrane fromulation, was developed under plane strain assumption for analyzing forming processes of an arbitrarily shaped draw-die of automotive panels. For the evaluation of bending effects with membrane elements, the bending equivalent forces and stiffnesses are calculated from the bending moment computed using the changes in curvature of the formed shape of two membrane ones. The curves depicted with 3 nodes are described by a circle, a quadratic equation, and a cubic equation, respectively, and in the simulation of the stretch/draw sections of an automotive inner panel, three different description results are compared each other. Also, the bending results are compared with membrane results and measurements in order to verify the validity of the developed program.