• Journal of Electrical Engineering and Technology
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• v.4 no.2
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• pp.229-233
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• 2009

This paper proposes a correction method for the error inherently created by time-step approximation in finite element analysis (FEA). For a simple RL and RLC linear circuit, the error in time-step analysis is analytically investigated, and a correction method is proposed for a non-linear system as well as a linear one. Then, for a practical inductor model, linear and non-linear time-step analyses are performed and the calculation results are corrected by the proposed methods. The accuracy of the corrected results is confirmed by comparing the electric input and output powers.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.6 s.249
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• pp.662-669
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• 2006

The pneumatic muscle actuator consists of an air bellows tube with two end-flanges. The air bellows tube is made from rubber layers and flexible sheathing formed from nylon 6 fibers. This structure can be stretched or compressed to convert the radial expansive forces into contractile forces. We performed the finite element analysis and the performance test of pneumatic muscle actuator. Also, the pneumatic muscle actuator was manufactured and tested by home-made tester. The results of FEA was similar with performance test below the maximum error of 42 %.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1633-1640
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• 2000

The finite element analysis (FEA) is widely used in modem structural dynamics because the performance of structure can be predicted in early stage. However, due to the difficult in determination of various uncertain parameters, it is not be easy to obtain a reliable finite element model. To overcome these difficulties, updating program of FE model is developed by consisting of pretest, correlation and updating. In correlation, it calculates modal assurance criteria, cross orthogonality, mixed orthogonality and coordinate modal assurance criteria. For the model updating, the continuum sensitivity analysis and design optimization tool (DOT) are used. The SENSUP program is developed for model updating to obtain physical parameter sensitivity. The developed program is applied to practical examples such as the base plate of HDD, BLDC spindle motor, and upper housing of induction motor. And the sensor placement for the square plate is compared using several methods.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.203-205
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• 1999

In this paper, voltage source FEA considering magnetic hysteresis characteristics is presented. Magnetization dependent model is used as a hysteresis model. The unknowns in finite element equation are the magnetic vector potential and current. Core model is analyzed and current waveform is compared with the experimental one. It is found that current can be accurately predicted with the voltage variation.

• Structural Engineering and Mechanics
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• v.55 no.1
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• pp.65-78
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• 2015

In recent years, implants have gained growing importance in all areas of medicine. The success of the treatment depends on many factors affecting the bone-implant, implant-abutment and abutment-prosthesis interfaces. In this paper, static and dynamic behaviors of the dental prosthesis are investigated. Three-dimensional finite element models of dental prosthesis were constructed. Dynamic loads in 5 sec applied on occlusal surface. Therefore, FEA was selected for use in this study to examine the effect of the static and dynamic loads on the stress distribution for an implant-supported fixed partial denture and supporting bone tissue.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.7
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• pp.591-598
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• 2011

This paper presents dynamic analysis of FCEV(fuel cell electric vehicle) turbo blower. To analyze the dynamic characteristics of turbo blower, FEA(finite element analysis) and experimental test are performed. Evaluations of stress safety for rotor sleeve and impeller due to rotational force and shrink fit are performed. Rotor dynamic analysis is conducted by Campbell diagram and structure vibration analyses are performed using FEA and experimental test. Through these results, noise sources of turbo blower are verified.

• Journal of the Society of Naval Architects of Korea
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• v.39 no.2
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• pp.69-80
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• 2002

Sequential process of roll-bending and line heating has been used to deform the curved hull-plates in shipyards. A growing interest for the mechanization or automation of the line heating process has been noted. Relations between heating conditions and residual deformations are important components needed for the mechanization. The residual deformations are investigated by using a thermal elastic-plastic analysis based on the finite element analysis(FEA). Several experiments are also performed to examine the validity of the results of FEA. The input parameters of line heating are suggested by dimensional analysis of line heating. The dimensional analysis can extract the primary input-parameters of line heating. The relations between the heating conditions and the residual deformations are set up by multi-variate analysis and multiple-regression method. This study suggests a method for the relation between the heating conditions and the deformations lying under the line heating.

• Composites Research
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• v.29 no.6
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• pp.388-394
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• 2016

Fiber reinforced plastic (FRP) composites have drawn increasing attentions worldwide for decades due to its outstanding properties. Stress concentration factor (SCF) as an essential parameter in materials science are critically considered in structure design and application, strength assessment and failure prediction. However, investigation of stress concentration in FRP composites has been rarely reported so far. In this study, three resource-conserving analyses (Isotropic analysis, Orthotropic analysis and Finite element analysis) were introduced to plot the $K_T^A-d/W$ curve for E-glass/epoxy composite plate with the geometrical defect of circular hole placed centrally. The plates were loaded to uniaxial direction for simplification. Finite element analysis (FEA) was carried out via ACP (ANSYS composite prepost module). Based on the least squares method, a simple expression of fitting equation could be given based on the simulated results of a set of discrete points. Finally, all three achievable solutions were presented graphically for explicit comparison. In addition, the investigation into customized efficient SCFs has also been carried out for further reference.

• Structural Engineering and Mechanics
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• v.88 no.5
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• pp.419-437
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• 2023

The use of reinforced concrete (RC) shear walls (SW) as an efficient lateral load-carrying system has gained recent attention. However, creating openings in RC shear walls is unavoidable due to architectural requirements. This reduces the walls' strength and stiffness, resulting in the development of wall piers. In this study, the cyclic behavior of RC shear walls with openings, reinforced with carbon fiber reinforced polymer (CFRP) sheets in various patterns, was numerically investigated. Finite element analysis (FEA) using ABAQUS software was employed. Additionally, the retrofitting of sub-standard buildings (5, 10, and 15-story structures) designed based on the old and new versions of the Iranian Code of Practice for Seismic-Resistant Structures was evaluated. Nonlinear static analyses, specifically pushover analyses, were conducted on the structures. The best pattern of CFRP wrapping was determined and utilized for retrofitting the sub-standard structures. Various structural parameters, such as load-carrying capacity, ductility, stress contours, and tension damage contours, were compared to assess the efficiency of the retrofit solution. The results indicated that the load-carrying capacity of the sub-standard structures was lower than that of standard ones by 57%, 69%, and 67% for 5, 10, and 15-story buildings, respectively. However, the retrofit solution utilizing CFRP showed promising results, enhancing the capacity by 10-25%. The retrofitted structures demonstrated increased yield strength, ultimate strength, and ductility through CFRP wrapping and effectively prevented wall slipping.

• Journal of Biosystems Engineering
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• v.30 no.6 s.113
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• pp.347-353
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• 2005

Paper angle, environment friendly packaging material, has been mainly used as an edge protector, But, in the future, paper angle will be applied to package design of heavy product such as strength reinforcement or unit load system (ULS). Therefore. understanding of buckling behavior fur angle itself, compression strength and quality standard are required. The objectives of this study were to characterize the buckling behavior by theoretical and finite element analysis, and to develop compression strength model by compression test for symetric and asymetric paper angle. Based on the result of theoretical and finite element analysis, as applied load level was bigger and/or the length of angle was longer, incresing rate of buckling of asymmetric paper angle was higher than that of symmetric paper angle. Decreasing rate of minimum principal moment of inertia significantly increased as the extent of asymmetric angle increased, and buckling orientation of angle was open- direction near the small web. Incresing rate of maximum compression strength (MCS) for thickness of angle decreased as the web size increased in symmetric angle. MCS of asymmetric angle of 43${\times}$57 and 33${\times}$67 decreased $15{\~}18\%$ and $65{\~}78\%$, and change of buckling increased $12{\~}13\%$ and $62{\~}66\%$, respectively.