• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2001년도 춘계학술발표대회 논문집
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• pp.50-53
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• 2001

An experimental research work for the fracture and notch strength of thick laminates has been performed to develop high quality composite notches for structural use. Thus, the multi-directional laminates are designed and compared to the baseline aluminum. The difference of notch strength caused by manufacturing techniques is also discussed. The notches of selected materials are evaluated by the static test and low-velocity impact test. Failure modes are also observed and assessed. Material design is evaluated by the FEA(finite element analysis) and confirmed by experiments. The successful results are obtained for thick composite notches, which shows higher strength than aluminum notches.

• 콘크리트학회지
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• 제11권1호
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• pp.129-139
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• 1999

본 연구는 콘크리트 구조물의 보강공법으로 널리 쓰이고 있는 강판에 의한 부착식 보강공법의 단점인 단부에서의 강판분리 현상에 대한 보완실험으로 실시되었다. 실험결과 노치가 적용된 강판부착식 공법이 항복하중 이후 최대하중까지의 증가율이 기존의 공법보다 증가되어 구조물의 보강 성능의 개선 및 안전성의 확보 측면에서 크게 개선되었을 뿐만 아니라 균열이나 처짐의 조절측면에서도 우수한 것으로 판명되었다. 이는 강판에 대한 약간의 변형만으로도 구조물의 수명을 연장시킬 수 있다는 장점과 함께 경제적으로도 보강된 구조물에 대한 추가적인 제반 비용의 절감도 기대할 수 있을 것이다.

• 대한치과보철학회지
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• 제18권1호
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• pp.15-35
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• 1980

The purpose of this study was to investigate stresses in the various components of fixed partial dentures restoring the posterior teeth of the lower jaw, and to measure quantitatively the effects of certain modifications in structural design on the stresses in the restorations using two-dimensional photoelasticity. Two-dimensional photoelastic methods were used in this study. Several models of fixed partial dentures were constructed. Shoulder less margins and anatomic occlusal reduction were incorporated in Model 1. Rounded shoulders and flat occlusal reduction were incorporated in Model 2, while Model 3 was a cantilever fixed partial denture. Other similar fixed partial dentures were constructed with V and U notches deliverately included in the region of the fixed joints for comparative reasons. The birefringent materials used in this study were PSM-1 and PSM-5 in standard sheets. PSM-1 was used for constructing the substructure, and PSM-5 was used in making the components of the fixed partial dentures. The two materials were used in the construction of composite photoelastic models. Improved artificial stone was used to represent dental cement in luting the composite photoelastic models. Static loading procedures were used at preplanned sites to represent occlusal loads in the mouth. 35 mm color and B/W film were used to record isochromatics in accordance with photoelastic procedures. Data reduction was performed using the grid method, which helped in, the mathematical integration procedure (Shear difference method) to separate the principal stresses. The results were as follows. 1. Fixed partial dentures do not function in bending as a symmetrical beam. Alternate areas of tension and compression were demonstrated when multiple contact loading was used. 2. The weakest part in posterior fixed partial dentures is the fixed joint. 3. (1) Models I and modified Model I were loaded on the pontic using a 50 pound vertical static load. The shear stress near the posterior fixed joint in Model 1 (U notches) was+129.4 p.s.i., and at the same fixed joint in modified Model 1 (V notches) was+239.4 p.s.i. The concentration of stress in fixed joint was reduced by 50% when U notches replaced the V notches. (2) Modified Model 2 was loaded using a multiple contact loader at a total load of 125 pounds. The difference between the principal stresses (${\sigma}_1-{\sigma}_2$), shear stress, at the V notches was+600 p.s.i., and at the U notches was+3l7 p.s.i. The shear stress was reduced by 50% when U notches replaced the V notches. V-grooves at the fixed joints should be avoided, and should be replaced by regular shaped U-grooves. 4. Cantilever fixed partial dentures had much higher stresses at the fixed joint than fixed partial dentures that were attached at both ends.

• Structural Engineering and Mechanics
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• 제38권5호
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• pp.619-631
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• 2011

This paper provides a complex variable BIE for solving the periodic notch problems in plane plasticity. There is no limitation for the configuration of notches. For the periodic notch problem, the remainder estimation technique is suggested. In the technique, the influences on the central notch from many neighboring notches are evaluated exactly. The influences on the central notch from many remote notches are approximated by one term with a multiplying factor. This technique provides an effective way to solve the problems of periodic structures. Several numerical examples are presented, and most of them have not been reported previously.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 추계학술대회 논문집
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• pp.145-148
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• 2003

This paper describes a new notches generator for the test of custom power devices such as UPS, DVR, Active Power Filter, etc. The magnitude, width, polarity, and position of the notches generated by the proposed scheme can be varied with simple control. The scheme has good features of simple structure, high reliability, and the capability of arbitrary several notches generation. The circuit operation is described and the usefulness of the scheme is verified through simulations.

• Computers and Concrete
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• 제16권4호
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• pp.605-623
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• 2015

A coupled experimental and numerical study of shear fracture in the edge-notched beam specimens of quasi-brittle materials (concrete-like materials) are carried out using four point bending flexural tests. The crack initiation, propagation and breaking process of beam specimens are experimentally studied by producing the double inclined edge notches with different ligament angles in beams under four point bending. The effects of ligament angles on the shear fracturing path in the bridge areas of the double edge-notched beam specimens are studied. Moreover, the influence of the inclined edge notches on the shear-fracture behavior of double edge-notched beam specimens which represents a practical crack orientation is investigated. The same specimens are numerically simulated by an indirect boundary element method known as displacement discontinuity method. These numerical results are compared with the performed experimental results proving the accuracy and validity of the proposed study.

• 한국정보통신학회논문지
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• 제8권8호
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• pp.1700-1704
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• 2004

본 논문에서는 공통접속점에서 임의의 노치 발생을 가능하게 하는 새로운 방식의 컨버터를 제안하였다. 제안한 방식에서의 노치 크기, 폭, 위치, 극성 등은 임의로 제어가 가능하며 제어회로 또한 매우 간단히 구성된다. 제안 회로는 간단한 구성, 높은 신뢰도, 저렴한 비용, 고효율, 제어의 용이함 등의 장점을 갖는다. 제안한 방식의 컨버터는 전력품질 개선장치로 사용되고 있는 무정전 전원공급장치, DVR, 능동전력필터 등의 성능시험에 유용하게 활용 가능하다. 제안 회로에 대한 동작원리와 특성을 기술하였으며 그 유용성을 시뮬레이션을 통하여 입증하였다.

• 드라이브 ㆍ 컨트롤
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• 제13권3호
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• pp.39-46
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• 2016

Flow and pressure ripple in swash plate type piston pumps is largely dependent on the design of notches(silencing grooves) in the valve plate. In uni-directional pumps, the basic design concept for notches in the valve plate could be said to be established. It is easily deduced that the design concept for notches in uni-directional pumps can not be simply applied to bi-directional pumps requested for EHA(electric hydrostatic actuators). To carry out systematic research on technological issues regarding notch applications to bi-directional piston pumps, five notch designs are devised. The effects of the notch designs on the characteristics of the pump are investigated by numerical simulations and experiments. Through this study, basic concepts about notch design for bi-directional piston pumps are suggested.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1999년도 제29회 춘계학술대회
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• pp.209-214
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• 1999

Dynamic pressure is one of the major sources on noise emission in hydraulic axial piston pump. This paper reports an experimental study of dynamic pressure characteristics in the cylinder port of hydraulic axial piston pump. We investigated dynamic pressure with not only the effect of delivery pressure, rotational speed and temperature but also V-notches at the ends of the kidney ports in the valve plate. We experimented three valve plates with three type V-notches at the ends of the kidney ports, because V-notches of the valve plate is known of noise reduction. Finally, we hope this paper help to design of the valve plate in hydraulic axial piston pump.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2003년도 봄 학술발표회 논문집
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• pp.35-42
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• 2003

This paper provides the first known flexural vibration data for thick (Mindlin) rectangular plates having V-notches. The V-notch has bending moment and shear force singularities at its sharp corner due to the transverse vibratory bending motion. Based upon Mindlin plate theory, in which transverse shear deformation and rotary inertia effects are considered, the Ritz procedure is employed with a hybrid set of admissible functions assumed for the rotational and transverse vibratory displacements. This set includes: (1) a mathematically complete set of admissible algebraic-trigonometric polynomials which guarantee convergence to exact frequencies as sufficient terms are retained; and (2) an admissible set of Mindlin corner functions which account for the bending moment and shear force singularities at the sharp corner of the V-notch. Extensive convergence studies demonstrate the necessity of adding the Mindlin corner functions to achieve accurate frequencies for rectangular plates having sharp V-notches.