• 한국레이저가공학회지
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• 제11권1호
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• pp.1-6
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• 2008

We proposed new light guide panel (LGP) fabrication method exploiting laser-processed inner scatterers and surface pattern. The proposed method has achieved LGP performance improvement in both brightness and uniformity. The inner scatterers and surface pattern of grid type were fabricated with a 2nd harmonic Nd:YAG pulse laser engraving system and a $CO_2$ laser scanning system, respectively. In the implementation of LGP, inner scatterers was arranged in accordance with linear or curved pattern with changing density and surface pattern was engraved on the surface of an inner-scatterers embedded LGP. The increase of scatterers' density and the use of surface patterns in both linear and curved pattern provided high luminance and uniformity enhancement. While thecurved pattern incorporated with increased scatterers' density and surface patterns yielded brightness improvement with preserving good uniformity, the linear pattern showed highly localized brightness near the light entrance of the LGP. We can also observe that the uniformity was mainly determined by pattern of inner scatterers, and the brightness was improved by the higher density and the utilization of surface patterns. From the results, the use of laser-processed inner and surface patterns can be a potential alternative for efficient and simple LGP fabrication method.

• Structural Engineering and Mechanics
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• 제68권5호
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• pp.527-536
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• 2018

The free vibration frequency responses of the graded flat and curved (cylindrical, spherical, hyperbolic and elliptical) panel structures investigated in this research considering the rectangular and tilted planforms under unlike temperature loading. For the numerical implementation purpose, a micromechanical model is prepared with the help of Voigt's methodology via the power-law type of material model. Additionally, to incur the exact material strength, the temperature-dependent properties of each constituent of the graded structure included due to unlike thermal environment. The deformation kinematics of the rectangular/tilted graded shallow curved panel structural is modeled via higher-order type of polynomial functions. The final form of the eigenvalue equation of the heated structure obtained via Hamilton's principle and simultaneously solved numerically using finite element steps. To show the solution accuracy, a series of comparison the results are compared with the published data. Some new results are exemplified to exhibit the significance of power-law index, shallowness ratio, aspect ratio and thickness ratio on the combined thermal eigen characteristics of the regular and tilted graded panel structure.

• 한국산학기술학회논문지
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• 제19권6호
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• pp.1-8
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• 2018

국내외에서는 $CO_2$ 저감 및 에너지 효율 증대에 관심의 초점이 되고 있으며 건설 분야 에서도 저탄소 녹색 성장을 위한 노력이 급증하고 있는 실정이다. 특히 FRP는 경량, 고강도, 고내구성 특성을 보유한 신소재로서 최근 국내외에서 제3의 건설소재로 대두되고 있다. 그러나 아직까지 터널이나 아치형 교량 등에 활용가능한 곡면형 FRP 건설자재에 대한 연구는 거의 이루어지지 않고 있으며 현재까지 곡면 구조재에 대한 연구는 프리캐스트 콘크리트에 대한 연구가 주를 이루고 있는 실정이다. 복합소재 패널 축소실험체는 실대형 실험체에 비하여 크기가 작기 때문에 다양한 실험을 수행 할 수 있다. 따라서 본 연구에서는 FRP 부재로만 구성된 중공형, FRP 부재에 콘크리트를 채운 단일 중실형과, 길이방향 연결부를 가지는 연결부 중실형, 그리고 FRP 부재와 콘크리트간의 부착력을 향상시킨 규사코팅 중실형에 대하여 실험을 수행하였다. 실험결과 길이 방향 연결부를 이용하여 복합소재 곡면패널을 결합할 경우에도 단일 부재와 거의 동등한 성능을 보인다고 판단된다. 하지만 실험체의 파괴시 가장 취약한 연결부에서 우선 파괴가 발생하기 때문에 향후 연결부 보강이 필요하다고 판단된다.

• Steel and Composite Structures
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• 제9권4호
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• pp.325-348
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• 2009

This paper is concerned with steel-concrete composite plate girders curved in plan. At the design stage these girders are assumed sometimes to act independent of the deck slabs resting on them in order to simplify the analysis. The advantage of composite action between the steel girders and concrete deck is not utilized. Finite element modeling of such composite action in plate girders is considered in this paper. Details of the finite element modeling and the non-linear analysis of the girders are presented along with the results obtained. Tension field action in the web panels similar to those observed in the straight plate girders is also noticed in these girders. Finite element and experimental results in respect of curved steel plate girders and straight composite plate girders tested by other researchers are presented first to assess the accuracy of the modeling. Effects of parameters such as curvature, steel flange width and web panel width that affect the behavior of composite girders are then considered in the analyses. An approximate method to predict the ultimate strength of horizontally curved composite plate girders is also presented.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 가을 학술논문 발표대회
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• pp.6-7
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• 2021

Although the development of free-form architectural technology continues, it consumes a lot of money and time due to the one-time formwork and the difficulty of maintaining quality due to manual work. To this end, in this study, a shape connection technique was proposed and verified to improve the limitations of implementing the curved surface of the existing lower multi-point press. In order to improve the accuracy of the shape, a curved surface was implemented using a silicon cap and a silicon plate. As a result of the error analysis of the shape, a small value of less than 3 mm was found. This study can implement more accurate curved surfaces than conventional technologies and produce high-quality free-form panels.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.1506-1511
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• 2003

This paper describes an automatic weld seam tracking method of plasma arc welding system designed for the corrugation panel that consists of a linear section and a curved section with various curvatures. Due to the complexity of the panel shape, it is difficult to find a seam and operate a torch manually in the welding process. So, the laser vision sensor for seam tracking is designed for sensing the seam position and controlling a torch automatically. To achieve precise seam tracking, the design of sensor head, image simulation, and calibration are carried out. Through a series of experiment result, compensation algorithm is added and real time error compensation is achieved. The experiment result shows that this vision sensor works effectively. It will provide more precise welding performance and convenience to the operator.

• Interaction and multiscale mechanics
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• 제1권3호
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• pp.339-355
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• 2008

A Galerkin meshfree method is presented for analyzing shear deformable cylindrical panels. Based upon the analogy between the cylindrical panel and the curved beam a pure bending mode for cylindrical panel is rationally constructed. The meshfree approximation employed herein is characterized by an enhanced moving least square or reproducing kernel basis function that can exactly represent the pure bending mode and thus meets the requirement of Kirchhoff mode reproducing condition. The variational form is discretized using the efficient stabilized conforming nodal integration with a smoothed nodal gradient based curvature. The resulting meshfree formulation satisfies the integration constraint for bending exactness. Moreover, it is shown here that the smoothed gradient preserves several desired properties which are valid for the standard gradient obtained by direct differentiation, such as partition of nullity and reproduction of a constant strain field. The efficacy of the proposed approach is demonstrated by two benchmark cylindrical panel examples.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 봄 학술논문 발표대회
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• pp.165-166
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• 2023

Free-form Concrete Panel(FCP) is each panel that composes the concrete exterior skin of Free-form building. FCPs contain curved surfaces, and FCPs have different curvature, size, and angles. In order to manufacture FCP, high technology is required, and it is currently difficult to manufacture it according to the design shape. In particular, many errors occur in the side shape of FCP. This is because when the side silicone mold is applied, it is installed without a coupling method between molds and support device. In this study, basic research was conducted to develop a side silicone mold support device to solve the above problems. We classified the required performance and derived the detailed requirements. Also, Based on this, we drew the basic design of the support device. We plans to conduct design improvement, mock-up making, and FCP manufacturing experiments through future research.

• 한국소음진동공학회논문집
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• 제22권2호
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• pp.115-122
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• 2012

Sound packages and damping materials have been widely applied on the floor to decrease the interior noise of a vehicle. Based on the previous researches on the low-noise vehicles, weight optimization through minimization of damping material usage is required while decreasing mid and high frequency range noise by application of sound packages. This paper describes the analysis process of robust design of vehicle body structure before applying damping materials and focuses on the analysis and test process of the location optimization at the stage of damping material application. A vibration experiment for the analysis of floor panel velocity with respect to the excitation of suspension attachment parts at the underfloor of a vehicle is performed. And through the improvement correlation between FEA and TEST, a design guide to optimize damping materials application in the early design stage is proposed. A research on vibration damping steel sheets and liquid acoustic spray on deadener(LASD) is performed to minimize manufacturing time and to minimize the space for pre-existing asphalt damping materials. As results of this study, panel stiffness is achieved through curved surface panel and bead optimization. And test baseline of optimum design is suggested through damping material optimization. And finally, through re-establishing the analysis process for vibration reduction of vehicle floors and lightweight design of damping materials, it is possible to design damping materials efficiently in the preceding stage of design.

• 대한환경공학회지
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• 제37권2호
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• pp.120-125
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• 2015

도시화의 가속화와 더불어 도심의 교통량의 증가로 도로소음피해를 최소화하기 위하여 방음벽의 설치 수요가 증가하고 있다. 설치되고 있는 여러 형태의 방음벽 중, 반사형 방음패널의 경우 불투명 방음패널과 달리 시야를 가리지 않으므로 방음시설을 요구하는 거주자들에게 인기를 얻고 있다. 하지만 반사형 방음패널의 경우, 반사음에 의한 2차 피해를 유발시켜 피해를 줄일 수 있는 방음벽 개발의 필요성이 대두되고 있다. 이에 본 연구에서는 반사형 방음패널의 전면형상 및 기하학적 형태를 변화시켜 반사음의 전달을 최소화 시킬 수 있는 형상을 연구하였다. 일반형 반사형 방음패널과 형상별 방음패널의 반사소음 저감 효과를 비교 한 결과, 곡선형 방음패널이 1.5 dB의 소음저감 효과가 있었다. 또한, 반사음의 증가 또는 감소는 형상별 설계인자에 따라 변화하는 것을 알 수 있었다. 이러한 결과는 방음벽 전면 현상에 따른 반사소음의 저감 기술의 가능성을 보여주는 결과라고 판단된다.