• Journal of the Korean Society for Nondestructive Testing
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• v.26 no.5
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• pp.343-352
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• 2006

In the present paper, the nondestructive test method was suggest to establish the bonding status of a motor case assembly composed of a steel motor case, adiabatic rubber layer and an ablative composite tube with strain data, AE(acoustic emission) signals and UT(ultrasonic test) data. And, finite element analysis was conducted to verify quantitatively the bonding status of motor case assembly under inner pressure loading. The bonding status could be judged whether the bonding status is perfect or contact condition by the data correlation study with AE signals and strain data measured from air pressure test. And, to classify the bonding status of motor case and rubber layer among bonding layers, UT method was also applied. From this study, the bonding status could be classified and detected into fourth types for all bonding layers as follows: (1) initial un-bonding, (2) perfect do-bonding during an air pressure test, (3) partially de-bonding during an air pressure test, and (4) perfect bonding.

• The Journal of Korean Academy of Prosthodontics
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• v.50 no.2
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• pp.99-105
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• 2012

Purpose: The change of the marginal bone around dental implants have significance not only for the functional maintenance but also for the esthetic success of the implant. The purpose of this study was to investigate the load transfer of internal conical joint type implant according to marginal bone resorption by using the three-dimensional finite element analysis model. Materials and methods: The internal conical joint type system was selected as an experimental model. Finite element models of bone/implant/prosthesis complex were constructed. A load of 300 N was applied vertically beside 3 mm of implant axis. Results: The pattern of stress distribution according to marginal bone resorption was similar. The maximum equivalent stress of implant was increase according to marginal bone resorption and the largest maximum equivalent stress was shown at model of 1 mm marginal bone resorption. Although marginal bone loss more than 1mm was occurred increasing of stress, the width of the stress increase was decreasing. Conclusion: According to these results, the exposure of thin neck portion of internal conical joint type implant is most important factor in stress increasing.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.7
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• pp.799-804
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• 2011

A thermal cycling test was conducted on a chip resistor solder joint with real-time failure monitoring. In order to study the failure mechanism of the chip resistor solder joint during the test, the resistance between both ends of the resistor was monitored until the occurrence of failure. It was observed that the monitored resistance first fluctuated linearly according to the temperature change. The initial variation in the resistance occurred at the time during the cycle when there was a decrease in temperature. A more significant change in the resistance followed after a certain number of cycles, during the time when there was an increase in the temperature. In order to explain the failure patterns of the solder joint, a mechanism for the solder failure was suggested, and its validity was proved through FE simulations. Based on the explained failure mechanism, it was shown that prognostics for the solder failure can be implemented by monitoring the resistance change in a thermal cycle condition.

• Journal of Information Technology and Architecture
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• v.11 no.2
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• pp.187-199
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• 2014

The DoD of United State, the MoD of United Kingdom and NATO have developed and implemented not only the concepts of joint capability but also management system for the joint capability to respond the future uncertain operations effectively. The resources of the DoD in United State have been efficiently planning, programming, budgeting, execution and evaluation using the PPBEE system which developed based on the concept of joint capability. The joint capability of the DoD has been managing through the JCAMS (Joint Capability Area Management System) which constructed based on JCA, UJTL and so on. Recently the MND of Korea eager to try introducing concept of the JCMS and developing the JCMS like the JCAMS of DoD for the future joint operation in the uncertain environment. We propose the holistic mechanism to develop the JCMS (Joint Capability Management System) of MND which can implement during the constructing the JCMS of Korea efficiently and effectively.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.1
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• pp.33-39
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• 2016

This study investigated the dynamic instability of a ceramic-on-ceramic artificial hip joint system through complex eigenvalue analysis. We examined the mode-coupling mechanism through eigenvalue sensitivity analysis with the variation of system parameters. In addition, we constructed a finite element model including the negative slope of friction curve for investigating the negative-slope mechanism in the hip squeak problem. The numerical results show that the torsion-dominant mode becomes unstable due to the presence of the negative slope while the axial load is the important factor influencing the negative-slope type instability.

• Journal of Korean Society of Steel Construction
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• v.25 no.3
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• pp.255-265
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• 2013

The major goal of this study is to develop the industrialized structural system that can build high-rise buildings using the box-shaped steel frames such as a unit module system. In order to achieve such a goal, we need the advanced details for joints that consist in a single unit. Furthermore we also need to commercialize the unit modular building system through the basic experiments, research of theoretical analysis and the achievement of seismic performance. This study derived to develop the derails in the beam-to-column joint and to carry out structural performance test. Test results, a joint with thickness of 6.0T can be possible to maintain the plastic rotational angle for strength and seismic performance. Therefore, joint with thickness of 6.0T is able to apply when considering reinforcement in the local of stress concentration.

• Journal of Ocean Engineering and Technology
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• v.17 no.1
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• pp.41-46
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• 2003

본 논문은 공간구조의 기본 요소인 피라미드형 구조단위에 대한 해석과 포스트텐션 시험의 결과를 기술하였다. 시험과정 중에 관찰된 거동 특성을 분석하고 수치해석의 결과와 비교 검토하였으며 시험모델에 대한 미케니즘(Mechanism)을 기하학적 해법으로 확인하였다. 이 논문의 결과는 다 방향성을 가진 조인트 시스템(Mero Joint System)을 이용한 공간구조의 거동을 정확하게 예측할 수 있고 비교적 작은 포스트텐션력으로 공간구조의 형성과 시공이 가능함을 제안하고 있으며 공간구조가 미케니즘을 포함할 경우 큰 변형이 일어나므로 비선형 거동을 고려해야 함을 나타내고 있다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.12
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• pp.1563-1571
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• 2011

In this study, we developed a finite element model of the human middle ear has been developed to calculate itsfor sound transfer characteristics calculation. We usedThe geometric data forof ossicles, obtained byfrom micro-CT scanning, was used in order to develop the middle- ear FE model. A right- side temporal bone of a Korean cadaver was used for the micro-CT scanning. The developed FE model includes three ossicles, the tympanic membrane, ligaments, and muscles. We calculated theA sound transfer function from the tympanic membrane to the stapes footplate was calculated. The sound transfer function calculated vias of the FE model shows good agreement with measured responses over the 10- kHz frequency band. To measureidentify the sensitivityies of the middle- ear function due to material property variation, we studied several parameters studies have been fulfilled using the middle ear FE model. TAs a result the stiffness property of the incudostapedial joint had the greatest influence onwas the most influential to the middle- ear sound transfer function among the parameters.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.2D
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• pp.237-245
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• 2011

Asphalt Plug Joint(APJ) is a new type of expansion joint that it's application are increased in USA as well as several European countries. APJ's' advantages are cheap construction and maintenance costs, and simple construction and securing of excellent flatness. However, APJ's usability is hindered because it showed a problem of premature failure. Research for solving this problem has been progressed, and FEM analysis among existing researches was peformed. However, the behavior of APJ was insufficiently analyzed and the reliability of the analysis was much low, since the material showing complicated behavior was oversimplified, Therefore, a material model was proposed and its effectiveness was confirmed by comparing it with actual behavior in order to improve the reliability of FEM analysis in this paper. ABAQUS program was used for FEM analysis, and an elasto-plastic model and a viscous-plastic model as the material model of APJ were suggested on the base of experiment results of APJ material performed by Bramel et al. The elasto-plastic model was defined by time-independent analysis since it didn't consider time and strain rate, and the viscous-plastic model was defined by time-dependent analysis since it considered. Influence of various elements affecting the behavior of APJ was investigated, and it was confirmed that the time-dependent analysis showed better result closed to actual behavior than the time-independent analysis.

• Journal of the Korea Convergence Society
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• v.2 no.4
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• pp.39-45
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• 2011

This paper examined the relationship between stress, the most potential cause among a variety of factors causing temporomandibular joint disorder, and temporomandibular joint disorder. In particular, this paper aimed to identify the temporomandibular joint disorder of those who were in their 20s, the age when temporomandibular joint disorder possibility increased. The survey was conducted by randomly selecting 120 college students who understood the purposes of this research and agreed to the survey from July 11 to 30, 2011. For the general features of the subjects, only gender showed any statistically significant difference. In the relationship between stress and habits related to temporomandibular joint disorder, the habit which the subjects had the most was "propping up of the chin", 64.4%. Five habits were observed the most frequently in the group with the highest stress. The habit of chewing on one side of the mouth showed the highest response as 81.5% in the group with high stress. Other habits showed similar results, about 60%.