• 반도체디스플레이기술학회지
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• 제6권1호
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• pp.59-64
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• 2007

Non-contact transportation of a large-sized glass plate using air cushion for the vertical sputtering system of liquid crystal display (LCD) panel was considered. The objective of the study was to design an air pad unit which was composed of multiple injection and exhaust holes and mass flow supplying pipe. The gas was injected through multiple small holes to maintain the force for levitating glass plate. After hitting the plate, the air was vented through exhaust holes. Complex flow field and resulting pressure distribution on the glass surface were numerically studied to design the air injection pad. The exhaust hole size was varied to obtain evenly distributed pressure distribution at fixed diameter of the injection hole. Considering the force for levitating glass plate, the diameter of the exhaust hole of 30 to 40 times of the gas injection hole was recommended.

• Computers and Concrete
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• 제21권1호
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• pp.75-85
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• 2018

To improve the design equation for the evaluation of the bursting force in the post-tensioned anchorage zone, this paper presents the analyses and design of the post-tensioned (PT) anchorage zone on the basis of three dimensional (3D) finite element (FE) analyses. The structural behavior was investigated through linear elastic finite element analyses upon consideration of the change in design parameters such as the bearing plate size, the eccentricity, and the tendon inclination. Moreover, consideration of the duct hole, which causes an increase of the bursting stress with a change in its distribution along the anchorage zone as well, is emphasized. Since that an exact prediction of the bursting force is the primary interest in design practice, additional parametric analyses are carried out to evaluate the relative contribution of all design parameters in determining the bursting force, and a comparison with the design guidelines mentioned in AASHTO-LRFD has been provided. Finally, an improved design guideline that takes into account the influence by the duct hole is suggested.

• 한국산학기술학회논문지
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• 제13권1호
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• pp.1-7
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• 2012

선박설계에 있어서 설계효율 향상 및 설계품질 확보를 위해서는 설계 자동화 시스템의 구축이 필수적이다. 이를 위해서는 조선전용 3차원 CAD 시스템의 개발과 함께 여러 설계 공정에서 발생되는 설계정보를 충돌 없이 자연스럽게 반영해 줄 수 있는 설계 정보 관리 소프트웨어들이 개발되어야 한다. 설계 정보 관리가 요구되는 대표적인 예로서 선체 의장품 시공에 필요한 의장 홀의 설계 과정을 들 수 있다. 설계 기간 중 빈번하게 발생하는 의장 부서로부터의 홀 시공 요구에 대하여 구조 설계 부서는 구조 안정성과 적합성을 고려하여 검토하고 반영 여부를 의장 부서로 통보하게 되며, 결정 시까지 부서간의 업무 협의, 토론, 관련 도면 작성 등 많은 설계자원이 투입된다. 본 논문에서는 이러한 의장 홀 설계 과정을 자동화하기 위한 홀 플랜 시스템의 기본 개념 소개와 함께 프로세스 자동화 방안을 제시한다.

• Nuclear Engineering and Technology
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• 제38권5호
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• pp.455-458
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• 2006

The HANARO reactor has a vertical hole for a cold neutron source (CNS) in the heavy-water reflector tank, i.e., the CNS hole, which was considerably deformed during its welding to the horizontal cold neutron (CN) beam tube. This paper presents an investigation of the form of the CNS hole for the optimal design of the a vacuum chamber for the CNS. In addition, the installation method of the vacuum chamber into the CNS hole for minimizing the water thickness between the vacuum chamber and the nose of the CN beam tube is proposed.

• Journal of Mechanical Science and Technology
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• 제15권12호
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• pp.1647-1654
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• 2001

The hole drilling method is widely used in measuring residual stress in surfaces. In this method, the inclination of holes is one of the sources of error. This paper presents a finite element analysis of the influence of inclined holes on the uniaxial residual stress field. The error in stress has been found to increase proportionally to the correct inclined angle of the hole. The correction equations by which one may easily obtain the residual stress, taking account of the inclined angle and direction, have been derived. The error of stress due to the inclined hole has been reduced to around 1% using the correction equations.

• Journal of Advanced Marine Engineering and Technology
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• 제18권4호
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• pp.62-68
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• 1994

Recently, the trends toward reduction in size and weight of industrial products increased the application of micro hole for manufacturing gadgets of high precision and gave rise to a great deal of interest for micro hole drilling M/C. Quite a few research work is performed on micro drilling on domestic basis compared with the tendency of analyzing cutting mechanism, adaptive control, monitoring of generally available drills of diameter greater than 1mm. This study adresses the design, manufacturing and controlling a micro hole drilling M/C with the overload detection instrument and the step feed mechanism. Controlling and monitoring of the drilling process are acomplished on PC basis for more user interfaces and effectiveness. The test machine of the results of this research shows a good foundation for extending further micro hole machining technique.

• 한국강구조학회 논문집
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• 제24권5호
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• pp.605-612
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• 2012

표준공으로 고장력볼트를 체결한 인장부재는 구조내력은 증가하지만 시공성이나 경제성 측면에서 문제점을 야기시키게 된다. 본 연구에서는 인장부재의 고장력볼트 체결부를 표준공 및 과대공으로 하는 총 28개의 시험편을 제작하여 인장시험을 실시하였다. 시험결과로부터 얻어진 표준공 및 과대공 시험편의 인장하중을 순단면 및 연단거리에 의한 설계강도와 비교하여 연결부의 강도변화를 확인하였다. 과대공으로 제작된 시험편의 인장하중은 표준공으로 제작된 시험편의 인장하중보다 감소하였으나, 현행 설계기준의 설계강도를 상회하였으며 과대공으로 인하여 다소의 강도저하는 부득이하지만 안전성을 만족하였다.

• 소성∙가공
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• 제25권1호
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• pp.36-42
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• 2016

Fiber metal laminates (FMLs) are well known for improved fatigue strength, better impact resistance, superior damage tolerance and slow crack growth rate compared to traditional metallic materials. However, defects and loss of strength of a composite material can occur due to the vertical load from the punch during the joining with a dissimilar material using a conventional clinching method. In the current study, tapered-hole clinching was an alternative process used to join Al 5052 and FMLs. The tapered hole was formed in the FML before the joining. For the better understanding of static and dynamic characteristics, a clinched joining followed by a tensile-shear test was numerically simulated using the finite element analysis. The design parameters were also evaluated for the geometry of the tapered hole by the Taguchi method in order to improve and compare the lateral joining strength of the clinched joint. The influence of the neck thickness and the undercut were evaluated and the contribution of each design parameter was determined. Then, actual experiments for the joining and tensile-shear test were conducted to verify the results of the numerical simulations. In conclusion, the appropriate combination of the design parameters can improve the joining strength and the cross-sections of the tapered-hole clinched joint formed in the actual experiments were in good agreement with the results of the numerical simulations.

• 대한기계학회논문집
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• 제19권3호
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• pp.605-614
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• 1995

In the automatic transmission using planetary gear there exists nonlinearities due to the finite difference between gear ratios, which yield torque hole during shift and influence on the ride quality and life of clutch. Based on the reaction carrier and converter turbine speed sliding functions are defined. Nonlinear closed-loop control laws are derived using them. Computer simulation shows that the closed loop design is better than the open loop design and semi-closed loop design.

• 한국기계가공학회지
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• 제6권4호
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• pp.15-21
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• 2007

The effect of manufacturing parameters on friction characteristics of motorcycle break system was studied using a disk-on-pad type friction tester. Such parameters conditions have an effect on the frictional factor such as number of ventilated disk hole, applied load, sliding speed, and sliding distance. However, it is difficult to know the mutual relation of these factors. In this study, the friction characteristics using design of experiment containing 4 elements were investigated for an optimal condition for the best motorcycle break system employing regression analysis method. From this study, the result was shown that the applied load in frictional factors was the most important, next to sliding speed, number of ventilated disk hole.