• 반도체디스플레이기술학회지
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• 제7권4호
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• pp.1-5
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• 2008

There is a need to enlarge the mother glass substrate in OLED to raise its productivity and to realize OLED TV. On the other hand, some difficulties may arise regarding the deflection of a large glass substrate during its handling operation due to its thinness $(0.5\sim0.7t)$, which is not even enough to allow it to stand its own mass. This thesis proposes a conceptual plan for the application of the clamping- and bending-end conditions to the glass substrate handler. To verify proposed plan, the non-contact 3 dimensional measuring instrument is developed. The composition of the 3 dimensional measuring instrument measures shape of the product using X-Y stage robot and laser distance sensor. X-Y stage robot and laser distance sensor are controlled by LabVIEW language. To calibrate measuring instrument, the direction conversion of the Euler angle was used. In order to confirm deflection of the glass substrate, the experiment was carried out at the bending end boundary condition and the proposed effect was verified.

• Journal of Mechanical Science and Technology
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• 제20권9호
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• pp.1371-1381
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• 2006

This paper deals with the active vibration control of a simply-supported beam traversed by a moving mass using fuzzy control. Governing equations for dynamic responses of a beam under a moving mass are derived by Galerkin's mode summation method, and the effect of forces (gravity force, Coliolis force, inertia force caused by the slope of the beam, transverse inertia force of the beam) due to the moving mass on the dynamic response of a beam is discussed. For the active control of dynamic deflection and vibration of a beam under the moving mass, the controller based on fuzzy logic is used and the experiments are conducted by VCM (voice coil motor) actuator to suppress the vibration of a beam. Through the numerical and experimental studies, the following conclusions were obtained. With increasing mass ratio y at a fixed velocity of the moving mass under the critical velocity, the position of moving mass at the maximum dynamic deflection moves to the right end of the beam. With increasing velocity of the moving mass at a fixed mass ratio ${\gamma}$, the position of moving mass at the maximum dynamic deflection moves to the right end of the beam too. The numerical predictions of dynamic deflection of the beam have a good agreement with the experimental results. With the fuzzy control, more than 50% reductions of dynamic deflection and residual vibration of the tested beam under the moving mass are obtained.

• 대한기계학회논문집B
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• 제34권6호
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• pp.599-606
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• 2010

본 연구에서는 다양한 작동조건(인가전압, 주파수)에 대하여 박막의 두께와 챔버의 직경이 열공압형 마이크로펌프의 액추에이터 박막의 거동 특성에 미치는 영향을 실험적으로 파악하기 위해 다양한 박막 두께와 챔버직경의 액추에이터를 제작하였다. 액추에이터는 파이렉스 표면에 위치한 마이크로히터, 챔버, 그리고 박막으로 구성된다. 모든 인가전압에 대하여 주파수가 10 Hz 이하로 감소함에 따라 박막 중앙의 최대 변위는 박막의 두께와 챔버의 직경에 관계없이 크게 증가한다. 낮은 주파수 영역에서 챔버로 공급되는 열량이 증가함에 따라 박막 중앙의 변위는 박막의 두께가 얇을수록, 챔버의 직경이 작을수록 증가한다. 10 Hz 이상의 주파수 영역에서 박막 두께, 챔버 직경, 공급 열량과 같은 모든 설계 변수가 박막 중앙의 변위에 미치는 영향은 미미하다.

• Journal of the Optical Society of Korea
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• 제18권5호
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• pp.523-530
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• 2014

Machine material and structural strain are critical factors for appraising mechanical properties and safety. Particularly in three and four-point bending tests, which appraise the deflection and flexural strain of an object due to external force, measurements are made by the crosshead movement or deflection meter of a universal testing machine. The Digital Image Correlation (DIC) method is one of the non-contact measurement methods. It uses the image analyzing method that compares the reference image with the deformed image for measuring the displacement and strain of the objects caused by external force. Accordingly, the advantage of this method is that the object's surface roughness, shape, and temperature have little influence. However, its disadvantage is that it requires extensive time to compare the reference image with the deformed image for measuring the displacement and strain. In this study, an algorithm is developed for DIC that can improve the speed of image analysis for measuring the deflection and strain of an object caused by a three-point bending load. To implement this algorithm for improving the speed of image analysis, LabVIEW 2010 was used. Furthermore, to evaluate the accuracy of the developed fast correlation algorithm, the deflection of an aluminum specimen under a three-point bending load was measured by using the universal test machine and DIC measurement system.

• Computers and Concrete
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• 제27권4호
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• pp.355-367
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• 2021

This paper investigates the mechanical response of simply supported one-way reinforced concrete slabs under fire through numerical analysis. The numerical model is constructed using the software ABAQUS, and verified by experimental results. Generally, mechanical response of the slab can be divided into four stages, accompanied with drastic stress redistribution. In the first stage, the bottom of the slab is under tension and the top is under compression. In the second stage, stress at bottom of the slab becomes compression due to thermal expansion, with the tension zone at the mid-span section moving up along the thickness of the slab. In the third stage, compression stress at bottom of the slab starts to decrease with the deflection of the slab increasing significantly. In the fourth stage, the bottom of the slab is under tension again, eventually leading to cracking of the slab. Parametric studies were further performed to investigate the effects of load ratio, thickness of protective layer, width-span ratio and slab thickness on the performance of the slab. Results show that increasing the thickness of the slab or reducing the load ratio can significantly postpone the time that deflection of the slab reaches span/20 under fire. It is also worth noting that slabs with the span ratio of 1:1 reached a deflection of span/20 22 min less than those of 1:3. The thickness of protective layer has little effect on performance of the slab until it reaches a deflection of span/20, but its effect becomes obvious in the late stages of fire.

• 한국기계가공학회지
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• 제15권3호
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• pp.115-121
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• 2016

A mackerel grader is a machine for sorting mackerel according to size. In this study, the dynamic deflection and optimal sorting simulation of a mackerel grader was carried out by using multi-body dynamics. To analyze the dynamic deflection of the roller, RecurDyn, a multi-body dynamics analysis program, was used. The dynamic deflection of the roller pipe was analyzed according to the inclination of the roller pipe. When the inclination of the roller pipe was 30 degrees, the roller indicated the maximum deflection of about 6.3 mm at the center of the mass. To simulate the mackerel sorting, the mackerel grader machine was modeled, and the contact simulation between the mackerel model and the rotating roller pipe was carried out. When the inclination of the roller frame was 7 degrees, the mackerel grader indicated optimal sorting performance.

• 대한기계학회논문집A
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• 제24권7호
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• pp.1681-1688
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• 2000

A dynamic model for the prediction of surface topography in high speed end milling process is developed. In this model the effect of tool runout, tool deflection and spindle vibration were taken in to account. An equivalent diameter of end mill is obtained by finite element method and tool deflection experiment. A modal parameter of machine tool is extracted by using frequency response function. The tool deflection, spindle vibration chip thickness and cutting force were calculated in dynamic cutting condition. The tooth pass is calculated at the current angular position for each point of contact between the tool and the workpiece. The new dynamic model for surface predition are compared with several investigated model. It is shown that new dynamic model is more effective to predict surface topography than other suggested models. In high speed end milling, the tool vibration has more effect on surface topography than the tool deflection.

• 한국기계가공학회지
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• 제16권4호
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• pp.89-96
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• 2017

A cable tray is a structure made of metal or a non-combustible material that supports cables in the electrical wiring of buildings. Cable trays should be developed to meet the various requirements of the construction site. In this study, a design system was developed to calculate the maximum support load and the maximum deflection according to the cross-sectional shape of the cable tray. The cross-sections of cable trays were modeled by combining linear and arc elements, and cross-sectional characteristics such as the 2nd moment of area were calculated. The distributed load and the concentrated load were applied to the cable tray using the Euler beam theory, and then the deflection profiles and maximum stress were calculated. To verify the developed system, deflection distributions and maximum stresses for two types of cable trays were calculated and compared. The maximum deflection and maximum stress errors calculated from the developed system were found to be less than 4% compared with numerical analysis results.

• 소성∙가공
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• 제22권6호
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• pp.310-316
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• 2013

Recently, numerical predictions of surface deflection based on curvature analysis have been developed. In the current study, a measure of surface deflection is proposed as the maximum variation of curvature difference between the panel and the tool in order to account for surfaces that have high curvature. The current study focused on the assessment of accuracy for the surface deflection prediction with the consideration of planar anisotropy. As an example, a shallow rectangular drawn part with rectangular embossing was considered. In terms of the proposed surface deflection measure, the maximum variation of curvature difference, the prediction with a planar anisotropic model shows better correspondence with experiment than the one using a normal anisotropic model.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.781-785
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• 2005

Cutting forces and tool deflection in end milling are represented as the closed form of tool rotational angle and cutting conditions. The discrete cutting forces caused by tool entry and exit are continued using the Fourier series expansion. Tool deflection is predicted by direct integration of the distributed loads on cutting edges. Cutting conditions, tool geometry, run-outs and the stiffness of tool clamping pan are considered for cutting forces and tool deflection estimation. Compared to numerical methods, the presented method has advantages in short prediction time and the effects of feeding and run-outs on cutting forces and tool deflection can be analyzed quantitatively. This research can be effectively used in real time machining error estimation and cutting condition selection for error minimization since the ferm accuracy is easily predicted by tool deflect ion curve.