• Journal of the Korean Institute of Gas
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• v.10 no.2 s.31
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• pp.40-46
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• 2006

In this paper, the optimized design of a rectangular O-ring groove has been analyzed for a maximum Cauchy stress and maximum strain using the Taguchi method. This method may efficiently optimize the design parameters for an O-ring groove of a LPG filling unit. The computed FEM results indicate that the optimized design parameters can only be drawn by nine experimental numbers of iterations when the Taguchi design technique has been employed with a finite element method. This means that the Taguchi design method is very useful for the optimization design of O-ring rectangular groove geometry. Based on the computed FEM results by the Taguchi design technique, the dimensions of a groove geometry are given as h=2.5 mm, d=2.74 mm, c=0.15 mm, and w=3.0 mm. In this study, the initial compression ratio of O-rings is recommended as 8.7% for a gas supply pressure of 18 $kg/cm^2$.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2000.11a
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• pp.102-105
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• 2000

Recently, applications of integrated large composite structures have been attempted to many structures of vehicles. To improve the cost performance and reliability of the integrated composite structures, it is necessary to judge structural integrity of the composite structures. For the judgement, we need fracture simulation techniques for composite structures. Many researches oil the fracture simulation method using FEM have been reported by now. Most of the researches carried out simulations considering only matrix cracking and fiber breaking as fracture modes, and did not consider delamination. Several papers have reported the delamination simulation, but all these reports require three-dimensional elements or quasi three- dimensional elements for FEM analysis. Among fracture mechanisms of composite laminates, delamination is the most important factor because it causes stiffness degradation in composite structures. It is known that onset and propagation of delamination are dominated by the strain energy release rate and interfacial moment. In this study, laminated composite has been described by using 3 dimensional finite elements. Then impact behavior of the laminated composite is simulated using FEM(ABAQUS/Explicit) with progressive failure mechanism. These results are compared with experimental results.

• Geomechanics and Engineering
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• v.27 no.5
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• pp.497-509
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• 2021

A large deformation FEM (Finite Element Method) based numerical analysis has been performed to study the behaviour of the bell-shaped anchor embedded in undrained saturated (cohesive) soil with the help of finite element based software ABAQUS. A typical model anchor with bell-diameter of 0.125 m, embedded in undrained saturated soil with varying cohesive strength (from 5 kN/m² to 200 kN/m²) has been chosen for studying the characteristic behaviour of the bell-shaped anchor installed in cohesive soil. Breakout factors have been evaluated for each case and verified with the results of experimental model tests for three different types of soil samples. The maximum value of breakout factor was found as about 8.5 within a range of critical embedment ratio of 2.5 to 3. An explicit model has been developed to estimate the breakout factor (F_c) for uplift capacity of bell-shaped anchor within clay mass in terms of H/D ratio (embedment ratio). It was also found that, the ultimate uplift capacity of the anchor increases with the increase of the value of cohesive strength of the soil and H/D ratio. The empirical equation developed in the present investigation is usable within the range of cohesion value and H/D ratio from 5 kN/m² to 200 kN /m² and 0.5 to 3.0 respectively. The proposed model has been validated against data obtained from a series of model tests carried out in the present investigation. From the stress-profile analysis of the soil mass surrounding the anchor, occurrence of stress concentration is found to be generated at the joint of anchor shaft and bell. It was also found that the vertical and horizontal stresses surrounding the anchor diminish at about a distance of 0.3 m and 0.15 m respectively.

• Land and Housing Review
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• v.4 no.3
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• pp.271-277
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• 2013

The BNWF (Beam on Nonlinear Winkler Foundation) model is one of the simplest idealizations for a pile embedded in soil as it ignores the continuity of the soil. This method is difficult to model the behavior of pile group foundation subjected to lateral loading. The limitation can be overcome with the utilization of the finite element method (FEM) or finite different method (FDM) to represent a pile element embedded in a soil medium. Both the ground and piles are modeled with soild elements. The solid elements, which do not have rotational degree of freedom, is not appropriate for modeling piles. It can be overcome by substantially increasing the number of elements, which can be prohibitive for 3D modeling. This paper used the beam element and rigid link incorporated in the OpenSees to model the pile. The accuracy of the model is validated through comparison with lateral load test and BNWF analysis. It is shown that the method can capture the measured behavior accurately. It is therefore recommended to be used in group pile analyses.

• Transactions of The Korea Fluid Power Systems Society
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• v.3 no.4
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• pp.14-20
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• 2006

Recently, the on-off solenoid valves have been focused on core technology in the fields of the production line of semi-conductor chips and the micro fluid chips for bio-medical applications. A key characteristics for on-off solenoid valve, operated by compressed air, are high speed response and great repeatability. Indeed, it is also important to keep the pressure on the cross-sectional area of the poppet to be constant regardless of the fluctuation of the pressure exerted on the ports. In this study, we have designed and analysed the high-speed and high flow rate on-off solenoid valve using the analogy of equivalent magnetic circuit and Finite Element Method (FEM) respectively. In case of poppet, flow field characteristics was analyzed by the variation of poppet and it was able to display flow field by changing the location of the poppet. Also, we verified possibility of the design through the static and dynamic pressure and the 3D simulation using distribution curve of the force by working the front poppet.

• Steel and Composite Structures
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• v.13 no.1
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• pp.15-33
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• 2012

For an axially loaded box-shaped member, the width-to-thickness ratio of the plate elements preferably should not be greater than 40 for Q235 steel grades in accordance with the Chinese code GB50017-2003. However, in practical engineering the plate width-to-thickness ratio is up to 120, much more than the limiting value. In this paper, a 3D nonlinear finite element model is developed that accounts for both geometrical imperfections and residual stresses and the ultimate capacity of welded built-up box columns, with larger width-to-thickness ratios of 60, 70, 80, and 100, is simulated. At the same time, the interaction buckling strength of these members is determined using the effective width method recommended in the Chinese code GB50018-2002, Eurocode 3 EN1993-1 and American standard ANSI/AISC 360-10 and the direct strength method developed in recent years. The studies show that the finite element model proposed can simulate the behavior of nonlinear buckling of axially loaded box-shaped members very well. The width-to-thickness ratio of the plate elements in welded box section columns can be enlarged up to 100 for Q235 steel grades. Good agreements are observed between the results obtained from the FEM and direct strength method. The modified direct strength method provides a better estimation of the column strength compared to the direct strength method over the full range of plate width-to-thickness ratio. The Chinese code and Eurocode 3 are overly conservative prediction of column capacity while the American standard provides a better prediction and is slightly conservative for b/t = 60. Therefore, it is suggested that the modified direct strength method should be adopted when revising the Chinese code.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1071-1072
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• 2011

The axial flux machine has higher power density than conventional radial flux machine, so it is widely applied to various industrial area, for instance, low speed wind power generator. For the conventional radial flux machine, 2D finite element method (FEM) is generally applied, but axial flux machine has to employ 3D FEM with long analysis time due to its own structural characteristic. This paper deals with the performance comparison of axial flux machine according to volume.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.20-27
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• 2006

중국 Three Gorges Project의 대수로사면 안정성은 설계와 시공측면에 있어 주요 관심사가 되었다. 사면 굴착으로 인한 제하과정에서 암반은 역학적으로 불안정한 상태에 놓인다. 본 논문은 FEM(2D-3D)를 이용하여 단층 암반 굴착으로 인한 암반사면의 안정성을 평가하였다. 해석결과 굴착 후 수로사면의 양측 수직벽과 분리울타리의 중간 상부에서 인장응력과 전단손상영역이 주로 발생하였다. 해석결과를 토대로 대규모 사면활동에 대한 안정성을 확인하였으나 시공단계에서 국부적 사면활동을 방지하기 위한 록볼트와 록앵커 등의 보강이 필요한 것으로 검토되었다.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.3
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• pp.159-167
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• 2006

According to industrial development, all fields using chemical instrument and material are generated an electrostatics. Electrostatic problems were very important part to all these components, moving system, printer, clothe machines etc. This paper was represented an analysis of electrostatic electrification by FEM (finite element method) of industrial type Inkjet plotter. Here electrostatics distribution analysis is accomplished by Maxwell-2D. We are showed an electrostatics generation source by rubbing and meager profits of electric charge. It know electronic values with each system position by experiment. These are decreased through earth and electricity shielding. Therefore this paper is proved by the simulation and experiment result.

• Journal of the Korean Geotechnical Society
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• v.15 no.1
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• pp.79-98
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• 1999

In the present study, a simple finite element method of analysis to predict non-uniform settlements at the interface between the mat foundation and foundation soils is proposed. Based on the proposed finite element method of analysis, the method to evaluate load sharing ratios of the foundation soils adjacent to the granular group piles is also presented. Further proposed is a procedure to estimate ultimate bearing capacity of the skirted granular group piles in a square pattern. To verify validity of the proposed methods and the estimated ultimate bearing capacity of the skirted group piles, comparisons are made with the results analyzed by using the PENTAGON3D FEM program. Finally, behavior characteristics with different reinforcement patterns of the skirts and the effect of an increase of ultimate bearing capacity due to the skirts are analyzed in connection with the design parameters.