• 한국정밀공학회지
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• 제13권9호
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• pp.165-173
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• 1996

The dimensional accuracy of a final product is mainly affected by elastic die deformation during the forging and elastic recovery after the ejection in cold forging process. The investigations on elastic recovery are not so much as those of elastic die deformation. The elastic recovery can be determined by using the elastic-plalstic finite element analysis, but, this method has some limits such as poor conver- gence and long computational time, etc. In this paper, a theoretical analysis for predicting the elastic recovery of a final product in axi-symmetric forging process by using the rigid-plastic finite element method is presented. The rigid-plastic finite element analysis of a cold forward extrusion process involving loading, ejecting process is accomplished by rigid-plastic FE code, DEFORM. The effect of elastic die deformation on the final product dimenmsion is also considered. The calculated elastic recovery is compared is compared with the analysis result of elastic-plastic FE code. ABAQUS.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 추계학술대회 논문집 학회본부
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• pp.49-52
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• 1989

Some limits are in two-dimensional analysis by finite element method to electromagnetic machine having finite dimension. Therefore three-dimensional analysis by finite element method, which are modeling original form of models are needed in order to gain accurate solutions. This paper present three-dimensional time varing magnetic field analysis method using electric field E and magnetic scarlar potential $\Omega$, and examine sample model.

• 전기의세계
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• 제29권10호
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• pp.660-666
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• 1980

The finite leement method is a effetive analysis technique for obtaining approximate solutions of continuum problems with boundary conditions. This paper deals with the programming for the application of this method and the preciser analysis of the magnetic field in the air gap of the linear stepper motor by the method. The finite element analysis based on the variational principle is adopted and the computer program for reducing input data and a large number of the memory words required by the system matrix is presented. The 2-dimensional analysis of the air gap is made and several cases according to varying the position are considered.

• 한국소음진동공학회논문집
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• 제12권2호
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• pp.141-149
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• 2002

Although the finite element method has become an indispensible tool for the dynamic analysis of structures, difficulty remains to quantify the errors associated with discretization. To improve the modeling accuracy, this paper proposes a method to make a combined use of finite elements and exact dynamic elements. Exact interpolation functions for the Timoshenko beam element are derived using the exact dynamic element modeling (EDEM) and compared with interpolation functions of the finite element method (FEM). The exact interpolation functions are tested with the Laplace variable varied. A combined use of finite element method and exact interpolation functions is presented to gain more accurate mode shape functions. This paper also presents a combined use of finite elements and exact dynamic elements in design/reanalysis problems. Timoshenko flames with tapered sections are tested to demonstrate the design procedure with the proposed method. The numerical study shows that the combined use of finite element model and exact dynamic element model is very useful.

• Structural Engineering and Mechanics
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• 제9권1호
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• pp.89-97
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• 2000

A modified constitutive model has been developed for nonlinear finite element analysis of axisymmetric reinforced concrete structures, and then implemented into an existing finite element program. By comparing with the experimental results available, the present model has been validated.

• Structural Engineering and Mechanics
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• 제16권6호
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• pp.655-674
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• 2003

Investigated in this study are the natural vibration characteristics of the coaxial cylindrical shells coupled with a fluid. Theoretical method is developed to find the natural frequencies of the shell using the finite Fourier series expansion, and their results are compared with those of finite element method to verify the validation of the method developed. The effect of the fluid-filled annulus and the boundary conditions on the modal characteristics of the coaxial shells is investigated using a finite element modeling.

• Structural Engineering and Mechanics
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• 제14권1호
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• pp.1-20
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• 2002

Investigated in this study are the modal characteristics of the eccentric cylindrical shells with fluid-filled annulus. Theoretical method is developed to find the natural frequencies of the shell using the finite Fourier expansion, and their results are compared with those of finite element method to verify the validation of the method developed. The effect of eccentricity on the modal characteristics of the shells is investigated using a finite element modeling.

• 대한전기학회논문지
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• 제40권1호
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• pp.24-30
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• 1991

This paper deals with the analysis of the transient characteristics of a superconducting a.c. generator(SCG) using Finite Element Method. Since the magnetic field induced by the field current and the armature currents are not sinusoidally distributed in a generator, the conventional equivalent circuit method, in general, uses the fundamental component only and is done in frequency domain. But the finite element analysis makes it possible to analyze the transient magnetic field distribution and the electrical characteristics of the double shields of SCG in time domain.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.137-140
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• 2004

Intervertebral cages in the cervical spine have been advantage in spinal fusion to relieve low back pain. In this study the effects of an intervertebral cage insertion on a cervical spine functional spinal unit investigate and cage structural analysis using finite element method. Three-Dimensional finite element models to create computed tomography (CT) scan C3-C4, obtain healthy young male which 1-mm slice section.

• 한국전산구조공학회논문집
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• 제31권4호
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• pp.199-206
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• 2018

범용유한요소프로그램인 Abaqus의 확장유한요소법(XFEM)의 사용성 검증을 위하여 2차원 모델에 적용하여 수치해석을 수행하였다. 기존의 연구에 많이 사용되었던 응집요소(cohesive element) 모델은 균열 경로를 예측하고 요소를 삽입하여야 하는 단점 때문에 실제 균열을 모사하는데 한계가 있다. 이러한 이유로 응력의 방향성 및 특이성을 바탕으로 균열의 경로를 예측하는 확장유한요소법(XFEM)이 균열 해석에 있어서 더 발전된 방법으로 이용되어 왔다. 이번 연구에서는 균열의 경로가 자명한 2차원 모델에 사용하여 응집요소해석과 XFEM에 응집요소의 물성을 적용한 해석을 비교하고 XFEM 적용의 타당성을 확인하였다. 수치해석으로 균열 발생 직전의 응력분포 및 응력 특이성을 확인하고 실제 균열 발생경로와의 비교를 한다. 본 연구를 바탕으로 몇 가지의 한계를 극복하면 실제 복잡한 모델의 실제 균열진전해석을 수행하여 균열을 모사할 수 있을 것으로 기대된다.