• 한국인터넷방송통신학회논문지
• /
• 제19권6호
• /
• pp.169-174
• /
• 2019

최근 원격통신용 미러의 정밀 제어를 위한 초정밀 구동 메커니즘 설계에 많은 연구가 진행되고 있다. 본 연구에서는 초정밀 구동 메카니즘의 구성 조건을 만족하기 위하여 마이크로미터(um)의 분해능을 가진 탄성힌지(flexure hinge)를 이용한 6자유도 스테이지 메카니즘을 제안한다. 탄성힌지를 조인트로 이용하여 공간상의 6자유도 스테이지를 설계하고, 탄성힌지의 탄성변형을 이용하여 반복적인 운동을 제공한다. 공간상의 6 자유도 스테이지를 개발하기 위하여 탄성힌지를 이용한 평면상의 2 자유도 스테이지를 설계하고 이를 조합하여 6 자유도 스테이지를 제작하였다. 유한요소 해석을 통하여 단위입력에 대한 최대 출력변위를 생성하는 탄성힌지의 크기와 형상을 결정하였고, 전체 스테이지를 구동 할 때, 개별 탄성힌지가 탄성 영역 안에서 구동됨을 유한요소 해석을 통하여 증명하였다. 또한 전체 스테이지 구동의 변위보정과 강성검증을 실험적으로 증명하기 위하여 CCD 레이저 변위센서를 이용한 스테이지 변위 해석을 진행하였다.

• Steel and Composite Structures
• /
• 제1권4호
• /
• pp.441-458
• /
• 2001

We analyzed the experimental and theoretical behavior of a particular type of steel joint designed to connect beam to beam and able to transfer both shear forces and bending moments. This joint is characterized by the use of steel plates and bolts enclosed in the width of the beams. The experimental investigation was carried out characterizing the constituent materials and testing in flexure beams constituted by two portions of beams connected in the middle with the joint proposed. Connections having different characteristics in terms of thickness of plates, number and type of bolts were utilized. Flexure tests allow one to determine the loaddeflection curves of the beam tested and the moment-rotation diagrams of the connections, highlighting the strength and the strain capacity of the joints. The proposed analytical model allows one to determine the moment-rotation relationship of the connections, pointing out the influence of the principal geometrical and mechanic characteristics of single constituents on the full properties of the joint.

• Structural Engineering and Mechanics
• /
• 제21권4호
• /
• pp.393-406
• /
• 2005

Cyclic loading tests were carried out on six half-scale reinforced concrete beam-column subassemblages designed to the current Chinese Seismic Design Code for Buildings. The deformation behavior and restoring force characteristics of the subassemblages were studied. Emphasis was directed on their seismic behavior and deformation components. Based on test data and a simplified analysis model of the global and local deformation, the contribution of the deformation components due to beam flexure, column flexure, joint shear, and slippage of longitudinal reinforcement in the joint to the global deformation of subassemblages at different displacement amplitudes of cyclic loading was investigated.

• 한국산업융합학회 논문집
• /
• 제26권6_1호
• /
• pp.993-999
• /
• 2023

In this paper, a novel polishing tool mechanism with 3-axis compliance is presented, which consists of 2-axis rotational and 1-axis linear compliances in series. The 2-axis rotational compliance mechanism is made up of four cantilever beams for adjusting rotational stiffness and one flexure universal joint at the center for constraining the z-axis deflection. The 2-axis rotational compliance can mechanically adjust the polishing tool to machined surfaces. The polishing press force can be simply controlled by using a linear spring along the z-axis. The 2-axis rotational and 1-axis linear compliance design is decoupled. The stiffness analysis of the 2-axis compliance mechanism was performed based on link compliance matrix and rigid body transformation. A 3-axis polishing tool was designed by configuring the 2-axis compliance mechanism and one linear spring.

• 한국정밀공학회지
• /
• 제29권1호
• /
• pp.25-32
• /
• 2012

In this study, we present a gripping mechanism that is inspired by caterpillar's proleg. A caterpillar's proleg has planta that gives compliance to the proleg by greatly deforming its shape. In the bio-inspired gripper, the planta is implemented by flexure joints. The flexures buckle when end force and end moment is applied on the joint in opposite direction. Using this characteristic, the gripping structure is designed so that the flexure buckling can occur. Flexure buckling increases the region where gripping force is constant and this region leads to increasing in gripping range. At the same time, flexure buckling decouples all spines and therefore all spines can move differentially and independently. With this simple but effective mechanism, the bioinspire gripper can achieve adaptive gripping on rough and rugged surfaces. A prototype is built to demonstrate adaptive gripping on rough and rugged surfaces such as cement block, brick.

• Architectural research
• /
• 제13권4호
• /
• pp.53-60
• /
• 2011

Damage detection algorithms based on a one-dimensional beam model can detect damage within a beam span caused by flexure only but cannot detect damage at a joint with prescribed boundary conditions or at the middle part of a beam section where the neutral axis is located. Considering the damage at a welded joint of beam elements in steel structures and modeling the damage with twodimensional plane elements, this study presents a new approach to detecting damage in the depth direction of the joint and beam section. Three damage scenarios at the upper, middle, and lower parts of a welded joint of a rectangular symmetric section are investigated. The damage is detected by evaluating the difference in the receptance magnitude between the undamaged and damaged states. This study also investigates the effect of measurement locations and noise on the capability of the method in detecting damage. The numerical results show the validity of the proposed method in detecting damage at the beam's welded joint.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2010년도 춘계학술대회 논문집
• /
• pp.335-336
• /
• 2010

• 한국안전학회지
• /
• 제33권5호
• /
• pp.70-77
• /
• 2018

In this study, the reinforced methods of joints were proposed to improve the structural performance of the enhanced spun reinforced concrete piles with joints. To verify the proposed methods, flexure performance was validated by finite element analysis considering both material and contact nonlinearity. Based on the previous study and those results of the analysis, it is concluded that the structural performance of the current joints system for the enhanced spun RC piles can be enhanced by applying the reinforced joints composed of extended circular band plates and studs. This proposed method showed the nearest structural behavior to the enhanced spun RC piles without joints. This numerical study will be used to further experimental study on the enhanced spun RC piles with reinforced joints.

• 한국구조물진단유지관리공학회 논문집
• /
• 제4권3호
• /
• pp.197-204
• /
• 2000

Tensile strength (stress) of bar splice is important in the research of mechanical behavior of reinforced concrete structures-beam, column etc.- with bar splice. The purpose of this research is to evaluate the flexural behavior - deflection of beam specimens, strain of main bars - of reinforced concrete beam with Lock Joint Coupler. To make a comparative research, reinforced concrete beam specimens with normal deformed bar and lap splice are tested and analyzed. Test results, Comparing a deflection of three types flexural specimens, a flexural specimen with Lock Joint Coupler is 40% greater than the other flexural specimens. At the center of flexural specimen, the strain of main bar(D29) with lock joint coupler is 50% less, and vice versa, at the point of 14cm far from the center of flexural specimen, the strain of main bar(D29) with lock joint coupler is 9% larger than the strain of main bar(D29) which calculated using the classical flexure theory. A discords, between a deflection behavior of the flexural specimens and a strain of the main bar, are caused by the difference of strain between the lock joint coupler and main bar, near the lock joint coupler. So, additional research is need to verify as stated above discords.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2008년도 추계 학술발표회 제20권2호
• /
• pp.9-12
• /
• 2008

반강접합은 핀접합의 단점을 보완하고 강접합의 장점을 수용할 수 있는 중간 형태이다. 현재 국내에서 핀접합에 대한 연구는 활성화 되어있으나 반강접합에 대한 연구는 많지 않기 때문에 본 연구에서는 3가지 형태의 실험체를 제작하여 성능을 입증하려 했다. 실험체는 강접합 HI-R, 반강접합 HI-S, 핀접합 HI-P등 총 3개이다. 실험결과 HI-R은 접합부 전단파괴, HI-S는 고정단 상부 휨파괴, HI-P는 경사계단 슬래브 하부 휨파괴로 나타났고 최대내력은 각각 51.74, 51.4, 24.63kN으로 측정되었고, 강성은 1.58, 1.19, 0.37을 나타냈다. 항복강도는 각각 44.5, 47.3, 24kN을 보유하고, 연성비는 3.31, 2.32, 1.54로 나타냈고, 사용하중 작용 시의 처짐은 KBC기준에 의거하여 HI-P실험체가 기준을 초과하는 것으로 나타났다. 철근 변형률분포로 보아 HI-S는 초기에 HI-R과 유사한 거동을 보이나 항복이후 접합부 내부요소들의 응력분담으로 핀접합보다는 우수한 성능을 보유한 반강접 접합부로 판단할 수 있었다.