• Journal of the Korea Institute of Military Science and Technology
• /
• v.8 no.4 s.23
• /
• pp.5-13
• /
• 2005

The impact of a long-rod penetrator into oblique plates with combined obliquity and yaw is investigated. The study was done using a newly developed three dimensional dynamic and impact analysis code, which uses the explicit finite element method. Through the comparison of simulation result with experimental result and other code's result, the adaptability and accuracy of the developed code is evaluated under the complex situation in which yaw angle and oblique angle exist simultaneously. As a result of comparison, it has found that deformed shape, residual length and velocity, rotational velocity of long-rod show good agreement with experimental data. Through this study, the applicability and accuracy of the code as a metallic armour system design tool is verified.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.9 no.1 s.24
• /
• pp.127-134
• /
• 2006

The protection capability against an enhanced long rod(L/D=30) with yaw is investigated numerically and compared with that of shorter one(L/D=15). In addition details of interactions between yawed long rods and oblique plate velocity are examined. Through the simulation results, we find that dual flying plates system is more effective with longer rod due to the elongated disturbance. The protection performance is more effective for the penetrator with $+6^{\circ}$ of yaw angle than that with a yaw angle of $-6^{\circ}$.

• Proceedings of the KSME Conference
• /
• 2000.11a
• /
• pp.724-729
• /
• 2000

In end milling process the undeformed chip thickness and the cutting force components vary periodically with phase change of the tool. In this study, up end milling process is transformed to the equivalent oblique cutting. The varying undeformed chip thickness and the cutting force components in end milling process are replaced with the equivalent average ones. Then it can be possible to analyze the chip-tool friction and shear process in the shear plane of the end milling process by the equivalent oblique cutting model. According to this analysis, when cutting SM45C steel, 72% of the total energy is consumed in the shear process and the balance is consumed in the friction process.

• Journal of the Korean Society for Precision Engineering
• /
• v.16 no.6
• /
• pp.190-196
• /
• 1999

In this study, a procedure for analyzing chip-tool friction and shear processes in 3-D cutting with a single point tool has been established. The edge of a single point tool including circular nose is modified to the equivalent straight edge, then 3-D cutting with a single point tool is reduced to equivalent oblique cutting. Transforming the conventional coordinate systems and using the measured three component of cutting forces, force components on the rake face and the shear plane of the equivalent oblique cutting system can be obtained. And it can be possible to assess the chip-tool friction and shear characteristics in 3-D cutting with a single point tool.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.13 no.2
• /
• pp.17-24
• /
• 2004

In end milling process, undeformed chip thickness and cutting forces vary periodically with phase change of the tool. Recently, a model has been proposed to simulate the shear and friction characteristics of an up-end milling process in terms of the equivalent oblique cutting to this. In the current study, a down-end milling process has been replaced with the equivalent oblique cutting process. And shear and tool-chip friction characteristics variation of SM45C steel has been studied using the end-mills of different helix angles. The specific shear and friction energy consumed with helix angle of $50^{\circ}$ is somewhat larger than those of$30^{\circ}$ and $40^{\circ}$. The specific shear energy consumed is about 76-77% of the specific cutting energy regardless the helix angles.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.25 no.10
• /
• pp.1520-1527
• /
• 2001

In end milling process the undeformed chip thickness and the cutting force components vary periodically with phase change of the tool. In this study, up end milling process is transformed to the equivalent oblique cutting. The varying undeformed chip thickness and the cutting force components in end milling process are replaced with the equivalent average ones. Then it can be possible to analyze the chip-tool friction and shear process in the shear plane of the end milling process by the equivalent oblique cutting model. According to this analysis, when cutting SM45C steel, 72% of the total energy is consumed in the shear process and the balance is consumed in the friction process.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.3 no.1
• /
• pp.48-51
• /
• 1976

Surveying the developmental degree of the crowns of mandibular first bicuspid in 566 korean children (264 males and 302 females) from 3 to 7 years of age by oblique cephalogram, the author got to the following results. 1. The developmental degree of the tooth crown of mandibular first bicuspid was earlier in female than in male. 2. The period of complete development of the crown of mandibular first bicuspid was 7 year 1 month in male and 6 year 3 month in female. 3. There was no significant difference in the period of complete development of the tooth crown compared with that of Japanese and American children.

• Proceedings of the KSR Conference
• /
• 2002.05a
• /
• pp.509-515
• /
• 2002

While performing the advisory services of the electrification of conventional lines for KTX(Korea High Speed Train), we faced the speed-up problem of catenary system for the existing narrow tunnel. To solve this problem, the new system, to be named "Oblique encumbrance tunnel catenary", was developed. This system is mainly characterized by a simple catenary type, a dual bracket, a oblique encumbrance, a small system height and the same bracket used for the radial tension load and compression one. In this paper, the basic concepts, overall system configuration and main points considered in a design phase for the ′oblique encumbrance tunnel catenary′ are described. Moreover, the detail design criteria and other contents like manufacturing pilot products and verifying the performance through a factory and site test are added.

• Journal of Ocean Engineering and Technology
• /
• v.26 no.2
• /
• pp.68-78
• /
• 2012

This study proposes an improved 3-D model that includes a new non-reflected wave generation system for oblique incident and multi-directional random waves, which enables us to estimate the effect of the various wave-types on 3-D wave fields in a coastal area with permeable submerged breakwaters. Then, using the numerical results,the three-dimensional wave field characteristics around permeable submerged breakwaters are examined in cases of oblique incident and multi-directional random waves. Especially, the wave height, mean surface elevation and mean flow around the submerged breakwaters are discussed in relation to the variation of incident wave condition.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2005.10a
• /
• pp.63-68
• /
• 2005

In this paper, 6-DOF motion equations of UUV (Unmanned Undersea Vehicles) are derived Moreover, the hydrodynamic maneuvering derivatives are found from the oblique towing tests of the 2m Manta type UUV model.