• Structural Engineering and Mechanics
• /
• 제19권3호
• /
• pp.297-320
• /
• 2005

In recent years the pure displacement formulation for plate elements has not been as popular as other formulations. We revisit the pure displacement formulation for shear-deformable plate elements and propose a family of N-node, displacement-compatible, fully-integrated, pure-displacement, triangular, Mindlin plate elements, MIN-N. The development has been motivated by the relative simplicity of the pure displacement formulation and by the success of the existing 3-node plate element, MIN3. The formulation of MIN3 is generalized to obtain the MIN-N family, which possesses complete, fully compatible kinematic fields, in which the interpolation functions for transverse displacement are one degree higher than those for rotations. General element-level formulas for the thin-limit Kirchhoff constraints are developed. The 6-node, 18 degree-of-freedom element MIN6, with cubic displacement and quadratic rotations, is implemented and tested extensively. Numerical results show that MIN6 exhibits good performance for both static and dynamic analyses in the linear, elastic regime. The results illustrate that the fully-integrated MIN6 element has excellent performance in the thin limit, even for coarse meshes, and that it does not require shear relaxation.

• 한국지진공학회논문집
• /
• 제7권6호
• /
• pp.71-80
• /
• 2003

구조물의 내진 성능을 정확히 평가하기 위해서는 비선형 시각 이력 해석이 필요하지만 실용성과 단순성 측면에서 약산법이 대안이 될 수 있으며, 다층 구조물을 등가 단자유도계로 치환할 때 다층 구조물의 모드벡터는 구조물이 탄성 또는 탄소성 상태에 상관없이 탄성 상태에서의 모드 형상으로 가정되지만, 항복이 발생한 후 증가하는 하중단계에서 구조물은 비탄성으로 되기 때문에 변위 모드 특성들도 변화된다. 본 논문은 항복 이후의 구조물의 모드 변화를 고려한 비선형 변위모드를 이용하여 다자유도계를 등가 단자유도계로 변환하는 방법을 제시하였으며, 변환된 등가 단자유도계의 변위응답을 근거로 추정한 복합 구조물의 최상층 변위와 실제 지진교란을 받는 복합 구조물의 비선형 동적해석에 의한 최상층 변위를 비교함으로서 복합구조물의 지진응답예측을 위한 비선형 변위모드법의 적용성과 신뢰성을 검토하였다.

• 한국콘텐츠학회논문지
• /
• 제11권8호
• /
• pp.59-67
• /
• 2011

디지털 콘텐츠가 디자인, 만화, 영상 등의 각 분야에서 대세로 자리 잡아 가고 있는 추세이다. 많은 디지털콘텐츠가 포토샵에서 제작되거나 일부 작업 과정에서 활용되고 있다. 포토샵의 다양한 기능 중에서도 특히 채널은 원리적 이해와 사용법이 어렵지만 중요한 고급 기능임에는 분명하다. 채널과 Displacement map은 채널의 음영정보를 사용하고 있다는 점에서 공통점이 있다. 음영정보는 '흰색과 검은색 및 흰색과 검은색 사이의 무채색으로 구성되는 256단계의 정보'이다. 채널의 음영정보는 Displacement map에서 '이동'의 개념으로 사용된다. Displacement map은 'Displacement map 이미지'의 채널이 가진 음영정보를 분석하여 Displacement map이 적용되는 '원본 이미지'의 픽셀을 이동시킨다. 이것은 이동시키는 특성을 활용하기 위하여 채널의 음영정보를 만들 수 있음을 의미한다. 본 연구는 대표적인 CG 프로그램인 포토샵의 Displacement map에서 음영정보가 적용되는 원리를 분석하고자하였다. 공학적인 알고리즘 연구보다는 채널의 음영정보가 어떤 원리로 적용되는 지를 분석하여 음영정보의 원리적 이해를 정리하고 분석하는데 의미를 두고 있다.

• 화약ㆍ발파
• /
• 제17권1호
• /
• pp.27-55
• /
• 1999

The excavation works for deep foundation in urban areas have recently increased complaints of blasting vibration and settlement of ground level. Foundation must be excavated approximately up to 24-28m depths from the surface. The roads and subway line pass through the excavation area. The Dae-chung station is also located at the nearest distance 5-35m from the working site. To protect subway station and adjacient some structures from blasting and settlement, the level of ground vibration, displacements and stress were monitored and analyzed. The results can be summarized as follows ; 1. An empirical particle velocity equation were obtained by test blasts at Nassan Missi 860 Office tel construction site. $V{\;}={\;}K(D/\sqrt{W})^{-n}$, where the values for n and k are estimated tobe 0.371 and 1.551. From this ground vibration equation, the max. charge weight per delay time against distance from blasting point is calculated. Detailed blasting method is also presented. 2. To measure the horizontal displacement in directions perpendicular to the borehole axis, 6 inclinometers installed around working sites. The displacement at the begining was comparatively high because the installation of struts was delayed, but after its installation the values showed a stable trend. Among them, the displacement by 3 inclinometers installed on a temporary parking area showed comparatively high values, for example, the displacement measured at hole No. IC-l recoded the max. 47.04mm for 6 months and at hole No. IC-2 recorded the max. 57.33mm for 7 months. So, all of these data was estimated below a safe standard value 103mm. 3. Seven strain gauge meter was installed of measure the magnitude and change of stress acted on structs. The measured value of maximum stress was $-465{\;}kgf/\textrm{cm}^2,{\;}-338.4{\;}kgf/\textrm{cm}^2,{\;}302.3{\;}kgf/\textrm{cm}^2$ respectively. In compareto the allowable stress level of steel, they are estimated to be safe.

• Radiation Oncology Journal
• /
• 제30권1호
• /
• pp.36-42
• /
• 2012

Purpose: To evaluate the radial displacement of clinical target volume in the patients with node negative head and neck (H&N) cancer and to quantify the relative positional changes compared to that of normal healthy volunteers. Materials and Methods: Three node-negative H&N cancer patients and five healthy volunteers were enrolled in this study. For setup accuracy, neck thermoplastic masks and laser alignment were used in each of the acquired computed tomography (CT) images. Both groups had total three sequential CT images in every two weeks. The lymph node (LN) level of the neck was delineated based on the Radiation Therapy Oncology Group (RTOG) consensus guideline by one physician. We use the second cervical vertebra body as a reference point to match each CT image set. Each of the sequential CT images and delineated neck LN levels were fused with the primary image, then maximal radial displacement was measured at 1.5 cm intervals from skull base (SB) to caudal margin of LN level V, and the volume differences at each node level were quantified. Results: The mean radial displacements were 2.26 (${\pm}1.03$) mm in the control group and 3.05 (${\pm}1.97$) in the H&N cancer patients. There was a statistically significant difference between the groups in terms of the mean radial displacement (p = 0.03). In addition, the mean radial displacement increased with the distance from SB. As for the mean volume differences, there was no statistical significance between the two groups. Conclusion: This study suggests that a more generous radial margin should be applied to the lower part of the neck LN for better clinical target coverage and dose delivery.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2008년도 춘계 학술발표회 제20권1호
• /
• pp.889-892
• /
• 2008

본 연구는 보통포틀랜드 시멘트(이하 OPC)의 제조공정 중 입도 분급에 의해 포집된 조분시멘트(이하 CC)와 저발열 혼화재료인 플라이애시(이하 FA)를 조합 치환하여 콘크리트에 미치는 수화발열특성에 대해 검토하고자 하였다. 실험은 W/B 50% 1수준에 대하여 OPC를 100% 사용한 것을 Plain 배합으로 하고, CC를 OPC에 대하여 25, 50, 75%의 3수준으로 치환하고, 혼화재로 FA를 0, 10, 20, 30, 40%의 5수준으로 치환하여 총 16배치를 계획 하였다. 실험결과로 유동성의 경우는 CC 치환율이 증가할수록 점점 감소하는 경향을 나타냈고, FA의 치환율이 증가할수록 증가하였다. CC 및 FA 치환율 별간이단열에 의한 온도 상승량은 치환율이 증가할수록 감소하였는데, 특히 FA40의 경우 CC치환율에 관계없이 최대 피크온도가 $7.3{\sim}8.9^{\circ}C$로 45%정도 아주 낮게 나타났다. 초기 압축강도는 CC 및 FA치환율 증가에 따라 비례적으로 저하하였는데, 재령경과에 따라 강도저하 폭은 감소하는 것으로 나타났다.

• 한국공작기계학회:학술대회논문집
• /
• 한국공작기계학회 2004년도 춘계학술대회 논문집
• /
• pp.376-380
• /
• 2004

This paper is to develop an optical ruer displacement sensor for monitoring high speed spindle. Proper magnitude of optical power as well as amplification of output signal are necessary to improve sensitivity of the sensor. In this paper, to meet the need of improvement of the sensor resolution, we choose proper optical power and amplification level through speculating on optical power of a laser diode.

• Smart Structures and Systems
• /
• 제9권3호
• /
• pp.273-286
• /
• 2012

As civil structures are exposed to various external loads, it is essential to assess the structural condition, especially the structural displacement, in every moment. Therefore, a visually servoed paired structured light system was proposed in the previous study. The proposed system is composed of two screens facing with each other, each with a camera, a screen, and one or two lasers controlled by a 2-DOF manipulator. The 6-DOF displacement can be calculated from the positions of three projected laser beams and the rotation angles of the manipulators. In the estimation process, one of well-known iterative methods such as Newton-Raphson or extended Kalman filter (EKF) was used for each measurement. Although the proposed system with the aforementioned algorithms estimates the displacement with high accuracy, it takes relatively long computation time. Therefore, an incremental displacement estimation (IDE) algorithm which updates the previously estimated displacement based on the difference between the previous and the current observed data is newly proposed. To validate the performance of the proposed algorithm, simulations and experiments are performed. The results show that the proposed algorithm significantly reduces the computation time with the same level of accuracy compared to the EKF with multiple iterations.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2002년도 봄 학술발표회 논문집
• /
• pp.125-130
• /
• 2002

The most important material parameters are fracture energy and the stress-crack opening displacement($\sigma$-w) curve to determine the behavior of concrete. Especially, the relationship between the $\sigma$-w curve is strongly important to determine the load-displacement curve of concrete that has a major influence on the fracture behavior of a concrete. In this paper, notched plain concrete beams with different strength level were tested under three-point bending and fracture energy, the load-deflection curve, and the load-crack mouth opening displacement(CMOD) curve were obtained from the experimental data. Also, the fictitious crack model(FCM) was applied to determine the load-deflection curve of notched plain concrete beams using various types of $\sigma$-w curve model proposed by Petersson and we compared experimental results with numerical ones carried out by Finite Element Method(FEM).

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2003년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
• /
• pp.137-139
• /
• 2003

In this paper, a design of VCM(Voice Coil Motor) for the measurement system of nano-level force and displacement was proposed and developed. This paper present the VCM shape for improvement of position resolution and guarantee of a large displacement. And then the finite element analysis method(FEM) utilized to produce linear driving thrust and satisfy required thrust of the system. The result shows the applicable possibility of the proposed VCM as a study for nano-level measurement system.