• Special Issue of the Society of Naval Architects of Korea
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• 2011.09a
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• pp.82-89
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• 2011

In general, a number of lifting lugs have been used in shipbuilding industry and the D-type lugs are mainly used. The aim of this paper is to increase the cycle of the use and to reduce the size of lifting lugs to introduce lightweight shackle. In this study, nonlinear elasto-plastic analysis has been performed to confirm the ultimate strength of lifting lugs. In order to evaluate the proper design-load distribution around lug eye, the contact force between lifting lug and shackle pin has been realized by gab element model. Gap element modeling and nonlinear analysis are carried out using the finite element program MSC/PATRAN & ABQUS. Additionally the ultimate strength tests were performed to verify the structural adequacy of newly designed lifting lug and to insure safety of it. The D-10, 15, 20 & 40 ton models which are mainly used in the block erection are selected in the strength test. According to the results of the analysis and strength test, the ultimate strength of the newly designed lifting lugs has been estimated to exceed 3 times of design working load.

• Structural Engineering and Mechanics
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• v.81 no.3
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• pp.305-316
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• 2022

Externally bonded ultrahigh performance fiber-reinforced concrete (UHPFRC) is commonly used as a strengthening material for reinforced concrete (RC) structures. This study reports the results of an experimental program investigating the bonding behavior between concrete and prefabricated UHPFRC plates. The overall experimental program is consisting of five RC specimens, which are strengthened using the different lengths and widths of prefabricated UHPFRC plates. These specimens were analyzed using the pull-pull double-shear test. The performance of each strengthened specimen is presented, discussed and compared in terms of failure mode, maximum load, load-slip relationship, fracture energy and strain distribution. Specimen C-25-160-300 which bonded along the whole width of 160 mm recorded the highest maximum load (109.2 kN) among all the analysed specimens. Moreover, a 3D numerical finite element model (FEM) is proposed to simulate the bond behavior between concrete and UHPFRC plates. Moreover, this study reviews the analytical models that can predict the relationship between the maximum bond stress and slip for strengthened concrete elements. The proposed FEM is verified against the experimental program and then used to test 36 RC specimens strengthened with prefabricated UHPFRC plates with different concrete grades and UHPFRC plate widths. The obtained results together with the review of analytical models helped in the formation of a design equation for estimating the bond stress between concrete and prefabricated UHPFRC plates.

• Journal of the Society of Naval Architects of Korea
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• v.42 no.6 s.144
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• pp.631-636
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• 2005

One and three dimensional whipping response analyses of a naval surface combatant subjected to an underwater explosion bubble pulse were carried out to compare the efficiency and accuracy according to the modeling methods. In 1-D analysis, program UNDEXWHIP developed by KIMM was used, which is based on the thin-walled Timoshenko's beam theory and on the modal analysis method using wetted vibratory modes of the hull girder. In 3-D analysis, three finite element models were suggested using LS-DYNA/USA code, such as 3-D beam model considering geometric shape of wetted side shell, coarse and fine 3-D F.E. models. Through the comparison of results from the 1-D and 3-D analyses, it could be confirmed that 1-D analysis result is in good agreement with 3-D analysis ones, and that fine 3-D F.E. model, shock analysis one, is also used both in the shock response and whipping response analyses for the analyst effort and time savings.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.11
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• pp.1757-1763
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• 2010

Flywheel energy storage system (FESS) is defined as a high speed rotating flywheel system that can save surplus electric power. The FESS is proposed as an efficient energy storage system because it can accumulate a large amount of energy when it is operated at a high rotating speed and no mechanical problems are encountered. The FESS consists of a shaft, flywheel, motor/generator, bearings, and case. It is difficult to simulate rotor dynamics using common structure simulation programs because these programs are based on the 3D model and complex input rotating conditions. Therefore, in this paper, a program for the FESS based on the 2D FEM was developed. The 2D FEM can model easier than 3D, and it can present the multi-layer rotor with different material each other. Stiffness changing of the shaft caused by shrink fitting of the hub can be inputted to get clear solving results. The results obtained using the program were compared with those obtained using the common programs to determine any errors.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.38 no.6
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• pp.332-336
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• 2012

Objectives: This study sought to evaluate fixation methods and determine the best method for the postoperative stabilization of maxillary osteotomy. For our analysis we performed a three-dimensional finite element analysis of stress distribution on the plate, screw, and surrounding bone, as well as displacement onto the plate. Materials and Methods: We generated a model using synthetic skull scan data; an initital surface model was changed to a solid model using software. Modified anterior segmental osteotomy (using Park's method) was made using the program, and four different types of fixation methods were used. An anterior load of 100 N was applied on the palatal surface of two central incisors. Results: The Type 1 (L-shaped) fixation method gave stresses of 187.8 MPa at the plate, 45.8 MPa at the screw, and 15.4 MPa at the bone around the plate. The Type 2 (I-shaped) fixation method gave stresses of 186.6 MPa at the plate, 75.7 MPa at the screw, and 13.8 MPa at the bone around the plate. The Type 3 (inverted L-shaped) fixation method gave stresses of 28.6 MPa at the plate, 29.9 MPa at the screw, and 15.3 MPa at the bone around the plate. The Type 4 (I-shaped) fixation method gave stresses of 34.8 MPa at the plate, 36.9 MPa at the screw, and 14.9 MPa at the bone around the plate. The deflection of the plates for the four fixation methods was 0.014 mm, 0.022 mm, 0.017 mm, and 0.018 mm, respectively. Conclusion: The Type 3 (inverted L-shaped) fixation method offers more stability than the other fixation methods. We therefore recommend this method for the postoperative stabilization of maxillary osteotomy.

• Journal of Technologic Dentistry
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• v.43 no.3
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• pp.99-105
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• 2021

Purpose: This study aims to examine the stress distribution effect of tightening torques of different abutment screws in a custom-abutment implant system on the abutment-fixture connection interface stability using finite element analysis. Methods: The custom-abutment implant system structures used in this study were designed using CATIA program. It was presumed that the abutment screws with a tightening torque of 10, 20, and 30 N·cm fixed the abutment and fixture. Furthermore, two external loadings, vertical loading and oblique loading, were applied. Results: When the screw tightening torque was 10 N·cm, the maximum stress value of the abutment screw was 287.2 MPa that is equivalent to 33% of Ti-6Al-4V yield strength. When the tightening torque was 20 N·cm, the maximum stress value of the abutment screw was 573.9 MPa that is equivalent to 65% of Ti-6Al-4V yield strength. When the tightening torque was 30 N·cm, the maximum stress value of the abutment screw was 859.6 MPa that is similar to the Ti-6Al-4V yield strength. Conclusion: As the screw preload rose when applying each tightening torque to the custom-abutment implant system, the equivalent stress increased. It was found that the tightening torque of the abutment influenced the abutment-fixture connection interface stability. The analysis results indicate that a custom-abutment implant system should closely consider the optimal tightening torque according to clinical functional loads.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.10
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• pp.4694-4699
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• 2013

In this paper, a high pressure cleaning machine in field was disassembled and measured in order to develop a highly improved pressure cleaner in performance and real configuration was modeled by using 3-D design program CATA V5. In addition, fluid analysis was conducted on the modeled high pressure cleaning machine by using ANSYS finite element analysis program and visualize the pressure changes of internal fluid flow was visualized. This result will be applied to a new designed high pressure cleaning machine in future.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.5330-5333
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• 2013

In this paper, a high pressure cleaning machine in field was disassembled and measured in order to develop a highly improved pressure cleaner in performance and real configuration was modeled by using 3-D design program CATIA V5. In addition, CFD analysis was conducted on the modeled high pressure cleaning machine by using ANSYS finite element analysis program and visualize the pressure changes of internal fluid flow was visualized. This result will be applied to a new designed high pressure cleaning machine in future.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.9
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• pp.4191-4196
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• 2013

In this paper, structural analysis was made on two cases in order to develop free rotational method and rotational angle in LCD monitor. The configuration of LCD monitor in field was modeled by using 3-D design program CATIA V5 and structural analysis was done to the modeled LCD in order to obtain stress, strain and total deformation by using ANSYS finite element analysis program.

• Proceeding of EDISON Challenge
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• 2016.03a
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• pp.268-268
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• 2016

기계적 장치의 도움 없이 오직 사람의 힘으로만 비행을 해야 하는 인간 동력 항공기는 높은 동력 효율 및 최소한의 무게를 지니며 고세장비(High Aspect Ratio)날개 특성을 가지고 있다. 따라서 공력 및 구조적 최적화가 필요하며 고세장비 날개 특성에 따른 대변위 해석이 필요하다. 비행가능한 특정 순항속도에서 3차원 날개에 작용하는 양력에 대해, Edison Solver(Educational program for finite element analysis (CASADSolver))를 이용하여 2차원 spar에 분포하중으로 적용하였을 때의 응력 분포 및 끝단 변위 분석하고자 한다. 또한, 2차원 spar에 일정한 간격으로 집중하중을 작용하였을 때 생기는 변위와 3차원 spar를 이용한 하중해석 결과의 변위를 비교하고자 한다. 위의 두 분석 결과로 비교적 계산자원이 많은 3차원 해석이 아닌 2차원 해석으로 인간 동력 항공기 날개 설계 초기단계에 적용가능한 지에 대해 비교한다.