• 산업경영시스템학회지
• /
• 제21권47호
• /
• pp.139-148
• /
• 1998

CALS IDB (Integrated database) is one of core technologies that embodies the principle of a shared data environment for the life cycle related data in CALS environment. In this study, to successfully share the data, we first classified the data types employed in the CALS environment and then discussed the data heterogeneity issued in data integration processes. To effectively solve this heterogeneity, we proposed the federated database systems as a candidate system especially focusing on the major functions and core element technologies.

• 한국전산구조공학회논문집
• /
• 제24권1호
• /
• pp.33-41
• /
• 2011

본 연구에서는 비부착형 포스트텐션 시스템의 해석에 적용할 수 있는 모델링기법을 제시하였다. 모델링은 유한요소 해석 프로그램을 이용하였으며, tube-to-tube contact 요소를 도입하여 강연선의 물리적 형상을 직접적으로 모델링하는 방법과 실제의 강연선 외에 가상의 강연선을 콘크리트에 매입하고, 두 개의 강연선을 스프링으로 연결하여 간접적으로 모델링하는 방법을 동시에 제시하고 비교하였다. 콘크리트의 인장경화 현상을 무시하였을때 두 모델링기법에서는 거의 동일한 결과를 제공하지만 콘크리트의 인장경화를 고려한 경우에는 스프링을 이용한 간접적인 모델링기법을 통해서만 결과를 얻을 수 있었으며, 결과 또한 콘크리트의 경화현상을 고려하지 않은 경우와 다소 상이하였다. 비교를 통하여 비부착형 포스트텐션 시스템의 모델링기법으로 스프링을 이용한 모델링기법을 최종적으로 선정하고 기존의 실험적 연구에서 인용한 실험결과와 해석결과를 비교, 검증하였으며 또한 파라미터 스터디를 통해서 모델링의 적절성을 확인하였다.

• Architectural research
• /
• 제18권3호
• /
• pp.113-120
• /
• 2016

The stability and resistance of the plates under in-plane loading is crucial in the design of structures. For the assessment of structural stability, it is necessarily required to have accurate finite element technologies. Therefore, the enhanced 9-node plate (Q9-ANS) element is introduced for the linear buckling analysis of plate where the critical buckling load has to be determined. The Q9-ANS is developed with the Reissner-Mindlin (RM) assumptions which consider transverse shear deformation of the plate. Assumed shear strain is used to alleviate the shear locking phenomenon. Numerical examples are carried out to verify the performance of the Q9-ANS element in calculation of critical buckling load of the plates.

• 연구논문집
• /
• 통권25호
• /
• pp.5-12
• /
• 1995

Mold platen are one of the most important structural components of the injection molding machine. Mold platen had been designed, and manufactured based on the experience and the method of trial and error. Recently, as the computer progress, the numerical simulation method using commercial finite element analysis code has been used to analyze the characteristics of components. It's a urgent problem to reduce the weight of mold platen while preserving the safety and reliability for the structual failure. Finite element analyses to establish basic design technologies and reducing the weight of mold platen were carried out. As result, we are obtained the about 10% reducing the weight for mold platen.

• 반도체디스플레이기술학회지
• /
• 제1권1호
• /
• pp.41-45
• /
• 2002

In modem manufacturing, new applations and technologies demand smaller, and functional devices to replace large systems. As miniaturization becomes a necessity, many companies are interested in small pumps for use in creating ultra-high vacuum, but past efforts to develop such systems have failed due to problems with vibration, stress, heat and power consumption. This paper shows analysis-based design techniques for high vacuum turbomolecular pump by finite element analysis.

• 전기학회논문지
• /
• 제65권5호
• /
• pp.878-882
• /
• 2016

These days, SFCLs are being developed in order to limit fault current. However, the superconducting elements that limit the fault current have such problems as capacity increase and require auxiliary devices including cooling device. If devices that comprise the current power network can withstand fault current for at least one cycle, it is possible to limit the fault current with current limiting elements by bypassing it on the fault line. In this study, the fault current limiter was configured with current transformer, vacuum interrupter, and current limiting element. Through the experience, it was confirmed that the fault current was limited within one cycle. The superconducting element, as a current limiting element, limited the fault current by 80 % within one cycle from fault occurrence, and the passive element limited it more than 95 %. Also, through the comparison between resistance curve and power consumption curve, it was confirmed that the current limiting element using a passive element was more stable than the superconducting element that required capacity increase and other auxiliary devices. It was considered that the FCL proposed in this study could limit fault current stably within one cycle from fault occurrence by using the existing power technologies such as fault current detection and solenoid valve operating circuit.

• 디지털산업정보학회논문지
• /
• 제18권3호
• /
• pp.83-95
• /
• 2022

A technology can be newly formed through technological convergence achieved by the intersection of two or more technological fields. As the complexity of technology development increases, related interest is increasing. Researches have been carried out on the concept, related indicators and analysis of technology convergence including method of social networks. This paper intends to suggest an analysis method of technology convergence using social networks based on the company's possessing technologies. According to the similarity of technologies among companies, a social network was constructed and the technology convergence was analyzed using k-core, a social network subgroup method. Using the result of k-core, base and element technologies for convergence was identified with their relations. Using the suggested method, technology convergence was analyzed on real technology data of defense-industry companies. When the minimum technology similarity is 0, the overall technology convergence relations between technology elements can be identified. In the scope of data in this paper, technologies of defense S/W, aircraft structure and structural materials are identified as important base technology for convergence.

• 한국소음진동공학회논문집
• /
• 제13권9호
• /
• pp.663-670
• /
• 2003

As the micro-technologies in the high precision manufacturing processes are developed, the demand for micro actuating device is increasing. But, it is difficult to achieve high resolution and wide operating range simultaneously with the conventional actuating systems which are contacting and type of dual servo system. So, the contact-free surface actuators whose movers are suspended or levitated were proposed. These systems can be applied to high precision stages and alignment apparatuses. The suspended mover can be assumed to be rigid body, but the mover is a structure in this study, therefore the vibration caused during the operating process has a serious adverse effect on the performance and it is very important to identify the vibrational characteristics. In this paper, a contact-free surface actuator is modeled in finite element method and updated by using the experimental modal data. Finally, the static and dynamic characteristics of the finite element model are predicted and then discussed.

• Advances in Computational Design
• /
• 제7권1호
• /
• pp.69-79
• /
• 2022

In this research, the aeroelastic instability of a tail section manufactured from aluminum isotropic material with different shell thickness investigated. For this purpose, the two degrees of freedom flutter analytical approach are used, which is accompanied with simulation by finite element analysis. Using finite element analysis, the geometry parameters such as the center of mass, the aerodynamic center and the shear center are determined. Also, by simulation of finite element method, the bending and torsional stiffnesses for various thickness of the airfoil section are determined. Furthermore, using Lagrange's methods the equations of motion are derived and modal frequency and critical torsional/bending modes are discussed. The results show that with increasing the thickness of the isotropic airfoil section, the flutter and divergence speeds increased. Compared of the obtained results with other research, indicates a good agreement and reliability of this method.

• 청정기술
• /
• 제3권2호
• /
• pp.1-12
• /
• 1997

The paper reviews the movement in the United States to supplement environmental regulations with volunteer programs that encourage institutions and industry to go beyond compliance to achieve greater reductions in their waste and emissions than might otherwise be accomplished through the exclusive reliance on increasingly rigorous "end of the pipe" regulations. These volunteer programs have as a common element the encouragement of "pollution prevention" as a preferable strategy. Pollution prevention is a term used in the US to describe strategies, technologies, policies, etc. that focus on eliminating waste and emissions at the source rather than just treating and controlling them. In some countries the term "Clean Technologies" is used rather than pollution prevention. In the paper the author reviews selected voluntary programs and reports on accomplishments to date for those programs.