• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2002년도 추계학술대회논문초록집
• /
• pp.401.2-401
• /
• 2002

An unconstrained tuning fork with a 3-D model has been numerically analyzed by Finite Element Method (FEM) and Boundary Element Method (BEM). The first three natural frequencies were calculated by the FEM modal analysis. Then the change of the modal frequencies was examined with the variation of the tuning fork length and width. (omitted)

• 소성∙가공
• /
• 제13권1호
• /
• pp.3-8
• /
• 2004

The improvement of dimensional accuracy for forged part is one of major goals in cold forging industry. There are many problems in controlling the dimension by the trial-and-error, especially for a precision forged gear. A FEM analysis has been used in developing the forging technology. However, FE techniques have to be reconfirmed for predicting accurately the dimension of forged part. In this study, the effects of elastic characteristics and temperature changes are investigated by the comparisons between experimental and FEA in cold forging. When FE models related with elastic characteristics are considered practically, FE results could predict the part dimension within the range of $10\mu\textrm{m}$. And if thermal effects also are considered additionally, the predicted dimensions are well coincided with the experimental down to about $5\mu\textrm{m}$.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2005년도 춘계학술대회 논문집
• /
• pp.1897-1900
• /
• 2005

The purpose of this study is to investigate the bending process for manufacturing of sound pipe by 3 dimension bending machine. The arbitrarily-bended pipe is widely used in a heat exchanger system. The pipe should be formed precisely for assembling of heat changer. And, spring back effect and variation of the pipe thickness should be controlled effectively. We described the change of spring back amount and thickness variation of the pipe according to the change of bending radius and bending angle by FEM analysis. The analysis is adopted the elasic-plastic analysis and contact analysis on MARC software.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2009년도 제40회 하계학술대회
• /
• pp.670_671
• /
• 2009

This paper presents a optimum design process for static torque characteristics of the Claw-Poles PM Stepping Motor(CPSM). Since the shape of CPSM changes along with axial direction, CPSM should only be analyzed by 3D-FEM. But 3D-FEM needs too much computation time and computer resources. Therefore, it is essential to reduce the number of 3D-FEM analysis models. In this paper, two design factors which affect the static torque characteristics of CPSM were selected. Optimum design process was able to make progress by using Pattern Search Algorithm and 3D-FEM. Finally, optimized model was compared with a conventional model.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2002년도 추계학술대회논문집
• /
• pp.1049-1053
• /
• 2002

An unconstrained tuning fork with a 3-D model has been numerically analyzed by Finite Element Method (FEM) and Boundary Element Method (BEM). The first three natural frequencies were calculated by the FEM modal analysis. Then the change of the modal frequencies was examined with the variation of the tuning fork length and width. Analytical model equations were derived from the numerically relating results of the modal frequency-tuning fork length by approximating minimization. Finally the BEM was used for the sound pressure field calculation from the structural displacement data.

• Advances in environmental research
• /
• 제3권2호
• /
• pp.117-129
• /
• 2014

Groundwater contamination is seeking a lot of attention due to constant degradation of water by landfills and waste lagoons. In many cases heterogeneous soil system is encountered and hence, a finite element model is developed to solve the advection-dispersion equation for layered soil system as FEM is a robust tool for modelling problems of heterogeneity and complex geometries. Recently developed Meshfree methods have advantage of eliminating the mesh and construct approximate solutions and are observed that they perform effectively as compared to conventional FEM. In the present study, both FEM and Meshfree method are used to simulate phenomenon of contaminant transport in one dimension. The results obtained are agreeing with the values in literature and hence the model is further used for predicting the transport of contaminants. Parametric study is done by changing the dispersion coefficient, average velocity, geochemical reactions, height of leachate and height of liner for obtaining suitability.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
• /
• 제48권6호
• /
• pp.316-321
• /
• 1999

Disk type single phase switched reluctance motor which is a simple robust construction, simple control circuit and low manufacturing cost, has a characteristics of axial and radial flux machines. However, because this DSPSRM has a complicated magnetic circuit, it is difficult to analyze the design characteristics.. In this study, the calculation of design parameter based on the conventional design theory of electric machine and the characteristics analysis by computer simulation was performed. As the DSPSRM has the characteristics of both AFM and RFM, it is difficult to analyze its characteristics by the 2D FEM. 3D FEM was applied in the analysis of energy distribution and approximated calculation of torque characteristics with rotor positions. With analysis results, prototype of DSPSRM is manufactured.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2009년도 춘계 학술발표회
• /
• pp.123-131
• /
• 2009

본 연구에서는 2차원 및 3차원 유한요소 해석을 이용하여 심층혼합처리 공법에 의한 연약지반 개량시 개량 심도를 결정 하였고, 그 결과는 다음과 같았다. 1. 2차원 해석 결과는 3차원 해석 결과 보다 약 10% 정도 크게 해석되었다. 2. 연약지반의 치환율이 5%이하 일 때 침하량은 급격히 증가하였다. 3. 심층혼합공법으로 연약지반 개량시 횡방향 간격 3m, 종방향 간격 6m, 그리고 8m의 심도로 개량하는것이 가장 경제적인 것으로 나타났다. 4. 심층혼합공법으로 연약지반 개량시 2차원 유한요소 해석보다 3차원 유한요소 해석으로 결정되어야 한다.

• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 2008년도 정기 학술대회
• /
• pp.156-159
• /
• 2008

This paper introduces a remained tensile force estimation method using SI technique based on evolutionary algorithm for externally prestressed tendon. This paper applies the differential evolutionary scheme to SI technique. A virtual model test using ABAQUS 3 dimensional frame model has been made for this work The virtual model is added to the tensile force(28.5kN). Two set of frequencies are extracted respectively from the virtual test and the self-coding FEM 2 dimension model. The estimating tendon tension for the FEM model is 28.31kN. It is that the error in the tendon tension is 1% through the differential evolutionary algorithm. The errors between virtual model and the self-coding FEM model are assumed as the model error.

• 한국전기전자재료학회논문지
• /
• 제20권10호
• /
• pp.869-872
• /
• 2007

In this study, in order to develop low temperature sintering ultrasonic nozzle, single-layer and multilayer ring-type piezoelectric actuators were manufactured using PMN-PNN-PZT ceramics, And then the electrical properties were investigated. A ring-type piezoelectric actuator was modeled by ATILA program using finite element method(FEM). The piezoelectric actuator dimension was $\Phi26.5$ (outer diameter), $\Phi12$ (inner diameter), 3.5 mm (thickness). By FEM analysis, resonant and anti-resonant frequencies were appeared as 56.7 kHz and 61.5 kHz. The displacement increased with the increases of the number of layer. Based on the result, ring-type multilayer piezoelectric actuators were manufactured at low co-firing temperature of $940^{\circ}C$. The resonant resistance decreased with the increases of the number of layer. And also, the capacitance increased with the increases of the number of layer. The mechanical quality factor (Qm) decreased with the increases of the number of layer.