• Nuclear Engineering and Technology
• /
• 제30권3호
• /
• pp.212-221
• /
• 1998

In the present study, a method for the dynamic analysis of a reactor core is developed. Peak responses for the motions induced from earthquake are obtained for a core model. The dynamic responses such as fuel assembly shear force, bending moment, axial force and displacement, and spacer grid impact loads are investigated. Prediction of fuel assembly stress during an earthquake requires development of a fuel assembly stress analysis model capable of interfacing with the models and results discussed in the dynamic analysis of a reactor core. This analysis uses beam characteristics which describe the overall fuel assembly response. The stress analysis method and its application for the case of an increased seismic level are also presented.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
• /
• pp.361-364
• /
• 2004

This paper predicts the shear stress-strain relationship of reinforced concrete columns using Transformation Angle Truss Model (TATM) considered bending moment and axial force effects. Nine columns with various shear span-to-depth ratios and axial force ratios were tested to verify the theoretical results obtained from TATM. Shear stress-strain relationship obtained from TATM was agreed well with test results conducted by bis study than other truss models.

• Journal of Advanced Research in Ocean Engineering
• /
• 제4권3호
• /
• pp.105-114
• /
• 2018

In the past, traditional methods of research on ship maneuvering performance were estimated in calm waters. However, the course-keeping ability and the maneuvering performance of a ship can be influenced by the presence of waves. Therefore, it is necessary to understand the maneuvering behavior of a ship in waves. In this study, the force acting on a moving ship and a rudder behind the model ship will be performed in regular waves in Changwon National University (CWNU). In addition, the prediction force acting on the rudder in calm waters was carried out and compared with those of Computational Fluid Dynamics (CFD). Model test in regular wave was performed to predict the force acting on the ship and the rudder behind the model ship in various wave directions. The effects of wavelength and wave direction on hydrodynamic forces acting on the ship hull versus rudder angle is discussed.

• 대한기계학회논문집A
• /
• 제29권7호
• /
• pp.983-989
• /
• 2005

The effects of mechanical parameters on the characteristics of chemical mechanical polishing(CMP) can be directly evaluated by friction force. The piezoelectric quartz sensor for friction force measurement was installed, and friction force could be detected during CMP process. Furthermore, friction energy can be calculated by multiplying relative velocity by integration of the friction force throughout the polishing time. $SiO_2$ slurry for interlayer dielectric(ILD) CMP was used in this experiment to consider the relation of frictional characteristics and polishing results. From this experiment, it is proven that the friction energy is an essential factor of removal rate. Also, the friction force is related to removal amount per unit length(dH/ds) and friction energy has corelation to the removal rate(dH/dt) and process temporature. Moreover, within wafer non-unifornity(WIWNU) is related to coefficient of friction because of the mechanical moment equilibrium. Therefore, the prediction of polishing result would be possible by measuring friction force.

• 한국기계가공학회지
• /
• 제15권4호
• /
• pp.40-45
• /
• 2016

Interrupted cutting has different cutting characteristics compared with continuous cutting. In interrupted cutting, the workpiece has a groove that regularly impacts the cutting tool and workpiece. Therefore, tool damage occurs rapidly, and this increases the cutting force and surface roughness. In this study, we performed interrupted cutting of carbon steel for machine structure (SM45C) using a coated carbide tool (TT7100). To predict the cutting force, we analyzed the experimental results with a regression analysis. The results were as follows: We confirmed that the factors affecting the principal force and radial force were cutting speed, depth of cut, and feed rate. From the multi-regression analysis, we deduced regression equations, and their coefficients of determination were 89.6, 89.27, and 28.27 for the principal, radial, and feed forces, respectively. This means that the regression equations were significant for the principal and radial forces but not for the feed force.

• 전기학회논문지
• /
• 제64권12호
• /
• pp.1695-1702
• /
• 2015

This paper presents the characteristic analysis and experiment of force characteristics in permanent magnet linear synchronous motor for accuracy prediction of linear motion machine tools. In particular, the pitching moment resulting from attraction force ripple has been analysed and tested. Firstly, we analysed the characteristics of detent force, attraction force, and pitching moment in permanent magnet linear synchronous motor according to the design techniques such as auxiliary teeth, chamfering, and permanent magnet skewing. In addition, we suggested the experimental set for measurement of pitching moment. Finally, the results from measurement shows the good agreement with those obtained from finite element analysis results.

• 한국정밀공학회지
• /
• 제13권12호
• /
• pp.151-157
• /
• 1996

The tool condition monitoring is one of the most important aspects to improve productivity and quality of workpiece. In this study, the wear of ceramic tool (A1$_{2}$0$_{3}$-TiC Series) cutting the hardened die material(SKD11) was investigated. Flank wear was more dominant than crater wear. Therefore the modeling of cutting force related to flank wear has been performed. The cutting force model was construct- ed by an assumption that the stress distribution on the tool face is affected by tool wear. The relationship between characteristics as cutting force and tool wear can be suggested by machining parameters depending on cutting conditions. Experiments were performed under the various cutting conditions to ensure the validity of force models. The theoretical predictions on the flank wear are approximately in good agreement with experimental results.

• 한국정보전자통신기술학회논문지
• /
• 제12권3호
• /
• pp.299-305
• /
• 2019

본 연구는 고령화와 젊은층의 이탈로 인한 농경사회에서 고령 및 여성 인력의 애로사항을 해결해주기 위해 시작되었다. 기존에 나와있는 농업용 고소리프트의 경우 전문 자격증 및 조작의 어려움과 평지가 아닌 불균형적인 도로 혹은 작업환경에 노출된 위험성과 여성들도 쉽고 효율적으로 생산적 농업을 할 수 있도록 하기 위하여 선행연구를 바탕으로 진행하였다. 먼저 농업용 포크리프트의 목적인 물체를 이용한 견인 성능 예측 모델을 통하여 시뮬레이션을 진행하고, 견인 성능 모델 수식을 이용하여 실험이 진행되고 있는 경남 김해시의 토양(점착력 34.125kPa, 내부마찰각 35.294deg, 외부마찰각 13.620deg, 부착력 5.750kPa, 평균 원추지수 0-15cm cl, 1001.8kPa)에 맞추었다. 시뮬레이션용 포크리프트의 경우 농업용 전동식 포크리프트의 구동력 및 운동저항 예측 모델링을 수식화하고 이를 바탕으로 모터 제어 드라이브는 AC모터 전용 드라이브인 1232E 모델을 적용, 프로그래밍을 통해 두 개의 드라이버를 각각 마스터와 슬레이브로 구분지어 구동할 수 있도록 하였고 메인 PCB에는 모터구동, 유압구동, 각종 출력을 제어할 수 있도록 시뮬레이션용 모델을 제작하였다. 제작된 시뮬레이션용 모델은 현재 지속적인 시뮬레이션과 수정 및 보완을 진행하고 있으며, 추후 본 연구를 바탕으로 보다 안전하고 효율성이 뛰어난 농업용 전동식 포크리프트의 개발을 위하여 연구를 지속할 예정이다.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2001년도 봄 학술발표회 논문집
• /
• pp.107-112
• /
• 2001

The IPC(Incremental Prestressed Concrete) which is gradually introducing the tensile force by tendons has been recently developed for reducing the effective depth of PSC bridges. As well known, concrete experiences long-term deformation such as creep and drying shrinkage, and the prediction of the long-term behavior of concrete bridges is essential for both safety and serviceability aspects. This paper was analysed the long-term behavior of a continuous 2-span IPC girder bridge taking into consideration of creep, drying shrinkage and the time of tensile force introduction. As results, the shrinkage of slab concrete increases the negative moment at interior support, and the The difference of concrete ages between slab and girder increases the camber. The effect of initial tensile force is larger than the effect of secondary tensile force in the tendons.

• 한국소음진동공학회논문집
• /
• 제21권9호
• /
• pp.834-841
• /
• 2011

Obtaining the real exciting force is important for the analysis of structural vibration or sound radiation to represent the actual condition. But in most cases, it is so difficult to get the actual force signals by direct measurement using sensors due to complex geometry. This paper suggests advanced source identification method which can be applied to the prediction of radiated noise considering correlations between measured signals. This method was implemented to the identification of the fan force in the refrigerator. The analysis of structural vibration and radiated noise caused by the fan force was also performed. The comparison between predicted SPL and measured SPL of the radiated noise by the refrigerator fan showed good agreement.