• Journal of Ocean Engineering and Technology
• /
• v.33 no.3
• /
• pp.214-221
• /
• 2019

A series of model tests was performed to evaluate the survivability of an articulated tower-type buoy structure under harsh environmental conditions. The buoy structure consisted of three long pipes, a buoyancy module, and top equipment. The scale model was made of acrylic pipe and plastic with a scale ratio of 1/22. The experiments were carried out at the ocean engineering basin of KRISO. The performance of the buoy structure was investigated under waves only and under combined environmental conditions from sea state (SS) 5 to 7. A nonlinear time-domain numerical simulation was conducted using the mooring analysis program OrcaFlex. The survivability of the buoy was analyzed based on three factors: the pitch motion, submergence of the top structure, and anchor reaction force. The model test results were directly compared to the results of numerical simulations. The effects of the sea state and combined environment on the performance of the buoy structure were investigated.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.24 no.6
• /
• pp.646-653
• /
• 2018

Marine accidents caused by dragging anchors occur constantly due to enlargement of ships' size and unusual weather conditions. Nevertheless, vessel operators rely on their experience because the calculations of actual holding power and external forces are complex and inconvenient. The purpose of this study was to propose a program for the anchor dragging risk assessment in order to provide crew and VTSO with the information to determine easily the danger of dragging and take appropriate action. The input data in this program were composed of the ship's basic particulars, anchoring condition, and external environment etc. on calculating for the wind pressure, frictional force, drift force, and holding power. Three dragging anchor accidents were applied to the program's data input at the time of the day, then the result was assessed by 'warning', which was verified with a high confidence. As a result, the risk of dragging anchors can be predicted in advance through this program. In further studies, it is necessary to simplify the input data and improve user convenience through automatic input from various equipment.

• Journal of the Korean Geotechnical Society
• /
• v.21 no.10
• /
• pp.123-131
• /
• 2005

In the present study, laboratory pull-out tests with screw anchors are carried out to investigate behavior characteristics of the anchors used in foundation system of underground structures which are applied to uplifting seepage forces. Small scaled pull-out tests in sand under saturated condition and dry condition were carried out. For estimating the group effects of the anchors, the upward displacement and the pullout load varied with spacing of the anchor were observed. The test results were compared with theoretical equation for the ultimate pull-out force. Also, the result of tests can be used to the finite element analysis program, $PENTAGON^{2D}$.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2004.11a
• /
• pp.781-784
• /
• 2004

Method of Steel plate reinforced by fiber sheet is advantageous in the secure loading facility. For this method are a light weight and a high strength, the thickness of steel can be reduced Effects of composite system are depreciated when the thickness of steel is thin. This is the result of the difference of ductility ratio with steel plate. Steel plate reinforced by fiber sheets confirms the ability of transformation. This is the result of the property of steel materials Steel plate reinforced by fiber sheet didn't display an enough performance when theadhesives are epoxy rosin. This is the result of the slide of the surface of stee1. The adhesive ability is varied by the number and span of anchor bolts. There wasn't happening the separation between steel and epoxy. Thus the method used in combination with anchor and epoxy is best excellent. This is the result of the upward of accumulation effects Shearing force is in proportion to the number of bolts. But the ability of shearing force per one bolt is reducing. Thickness of steel plate reinforced by fiber sheet must be designed so that steel is endure before concrete is wreck.

• Structural Engineering and Mechanics
• /
• v.84 no.5
• /
• pp.591-604
• /
• 2022

A gravity wall combined with an anchoring lattice frame (a combined retaining structure) is adopted at a typical engineering site at Dali-Ruili Railway Line China. Where, the combined retaining structure supports a soil deposit covering on different inclined rock slopes. With an aim to investigate and compare the effects of inclined rock slopes on the response of combined retaining structure under seismic excitation, three groups of shaking table tests are conducted. The rock slopes are shaped as planar surfaces inclined at angles of 20°, 30°, and 40° with the horizontal, respectively. The shaking table tests are supplemented by dynamic numerical simulations. The results regarding the horizontal acceleration response, vertical acceleration response, permanent displacement mode, and axial anchor force are comparatively examined. The acceleration response is more susceptible to outer structural profile of combined retaining structure than to inclined angle of rock slope. The permanent displacement decreases when the inclined angle of the rock slope increases within a range of 20°-40°. A critical inclined angle of rock slope exists within a range of 20°-40°, and induces the largest axial anchor force in the combined retaining structure.

• Journal of the Korean GEO-environmental Society
• /
• v.14 no.8
• /
• pp.37-44
• /
• 2013

The superiority of bearing ground anchor system has been recognized for the stability and economical efficiency since 1950s in Japan, Europe and etc. The ground anchor introduced in Korea, however, has the structural problem that the tensile strength comes only from the ground frictional force caused by the expansion of the wedge body and it is impossible to evaluate the bearing resistance because the adhering method of the anchor body to hollow wall is not appropriate. In this study, the underreamed ground anchor system was developed so that the bearing pressure of ground anchor can exert as much as possible. And the in-situ tests were performed to evaluate the pullout behavior characteristics and to verify the decreasing effect of the bonded length. The pullout tests were performed with the non-grouted tension condition and grouted tension condition in order to identify the pull-out resistance of each conditions. In addition, it was compared with the results of friction anchor. Finally, the numerical analysis was fulfilled to verify the bearing effect at the bonded part through the detailed modeling by PLAXIS-2D, which is general finite element method analysis program.

• The korean journal of orthodontics
• /
• v.24 no.3 s.46
• /
• pp.721-733
• /
• 1994

Orthodontic tooth movement is closely related to the stress on the periodontal tissue. In this research the finite element method was used to observe the stress distribution and to find the best condition for effective tooth movement in the case of unilateral molar expansion. The author constructed the model of lower dental arch of average Korean adult and used $.032'\times.032'\times60mm$ TMA wire. The wire was deflected in the horizontal and vertical direction to give the 16 conditions. The following results were obtained ; 1. When the moment and force were controlled properly the movement of anchor tooth was minimized and the movement of moving tooth was maximized. 2. As the initial horizontal deflection increased the buccal displacement of both teeth was also increased. As the initial horizontal deflection increased the lingual movement of anchor tooth and the buccal movement of moving tooth increased. 3. When the initial horizontal and vertical deflection rate was 1.5 the effective movement of moving tooth was observed with minimal displacement of anchor tooth.

• Journal of Ocean Engineering and Technology
• /
• v.31 no.3
• /
• pp.219-226
• /
• 2017

In this study, the impact characteristics of subsea pipelines that were installed in various soil types and burial depths were evaluated by a numerical method. An impact scenario replicated a dropped ship anchor that fell vertically and impacted an installed subsea pipeline. In order to calculate the impact force through terminal velocity, FLUENT, a computational fluid dynamic program and MDM (Moving Deforming Mesh) technique were applied. Next, a dynamic finite element program, ANSYS Explicit Dynamics, was used for impact analysis between the anchor and pipeline (or, subsea if they were buried). Three soil types were considered: loose sand, dense sand and soft clay by applying the Mohr-coulomb model to the seabed. The buried depth was assumed to be 0 m, 1 m and 2 m. In conclusion, a subsea pipeline was the most stable when buried in dense sand at a depth of 2 m to prevent impact damage.

• Journal of Korean Orthopaedic Sports Medicine
• /
• v.10 no.2
• /
• pp.117-120
• /
• 2011

Avulsion rupture of the flexor digitorum profundus tendon at the distal phalanx is a rare injury. It usually occurs during extension of the DIP joint, while the flexor digitorum profundus tendon is contracted, or when strong extension force is applied, to the distal phalanx. We experienced a patient, combat policeman who had avulsion rupture of flexor digitorum profundus tendon at the distal phalanx after 2 days of combat exercise. Here, we would like to report unusual case of rare tendon injury with studies from other papers.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2009.03a
• /
• pp.677-685
• /
• 2009

From the result of precise field investigation and stability examination for the cut slope, following results were acquired. 1. The cause of the cut slope collapse seems that it came from complex actions such as the weathering rock itself, existing fault zone and crack from excessive blasting. 2. As a result of analysis, it is appeared that the cut slope can be in danger of plane destruction. 3. The reinforcement force is decided by the result of limit equilibrium analysis. 4. For reinforcement the method after relaxing the slope was judged as the most proper method to the cut slope as comparing/analyzing Rock Anchor, Rock Bolt and method after relaxing the slope.