• International Journal of Aeronautical and Space Sciences
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• 제18권3호
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• pp.450-466
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• 2017

This paper defines the modified effective membrane stiffness, bending stiffness considering the directionally dependent mechanical properties and mode shape function of a composite lattice rectangular plate, which is assumed to be a Kirchhoff-Love plate. It subsequently presents an approximate method of conducting a buckling analysis of the composite lattice rectangular plate with various boundary conditions under uniform compression using the Ritz method. This method considers the coupled buckling mode as well as the global and local buckling modes. The validity of the present method is verified by comparing the results of the finite element analysis. In addition, this paper performs a parametric analysis to investigate the effects of the design parameters on the critical load and buckling mode shape of the composite lattice rectangular plate based on the present method. The results allow a database to be obtained on the buckling characteristics of composite lattice rectangular plates. Consequently, it is concluded that the present method which facilitates the calculation of the critical load and buckling mode shape according to the design parameters as well as the parametric analysis are very useful not only because of their structural design but also because of the buckling analysis of composite lattice structures.

• Steel and Composite Structures
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• 제52권1호
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• pp.89-107
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• 2024

This article focuses on the static and dynamic analysis and optimization of an anisogrid lattice plate subjected to axial compressive load with simply supported boundary conditions. The lattice plate includes diagonal and transverse ribs and is modeled as an orthotropic plate with effective stiffness properties. The study employs the first-order shear deformation theory and the Ritz method with a Legendre approximation function. In the realm of optimization, the Non-dominated Sorting Genetic Algorithm-II is utilized as an evolutionary multi-objective algorithm to optimize. The research findings are validated through finite element analysis. Notably, this study addresses the less-explored areas of optimizing the geometric parameters of the plate by maximizing the buckling load and natural frequency while minimizing mass. Furthermore, this study attempts to fill the gap related to the analysis of the post-buckling behavior of lattice plates, which has been conspicuously overlooked in previous research. This has been accomplished by conducting nonlinear analyses and scrutinizing post-buckling diagrams of this type of lattice structure. The efficacy of the continuous methods for analyzing the natural frequency, buckling, and post-buckling of these lattice plates demonstrates that while a degree of accuracy is compromised, it provides a significant amount of computational efficiency.

• 대한기계학회논문집
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• 제16권6호
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• pp.1021-1029
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• 1992

본 연구에서는 거대한 평판형 격자구조물에 대한 등가 연속체모델을 유도하기 위한 보다 간편하고 합리적인 방법을 개발하고, 예제해석을 통해 새로이 개발된 방법 의 타당성을 보이는데 있다.

• 콘크리트학회논문집
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• 제17권2호
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• pp.191-200
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• 2005

무량판 구조의 슬래브-기둥 접합부는 취성적인 전단유형으로 파괴되며, 이는 전 구조물의 붕괴를 유발할 수 있다. 본 연구에서는 새로운 전단보강방법으로서 래티스 철근을 이용한 전단보강방법을 개발하였다. 실험연구를 실시하여 래티스 전단보강 실험체와 무보강 실험체의 접합부 전단강도 및 연성도를 비교하였다. 실험결과 래티스 철근으로 전단보강한 실험체는 전단보강하지 않은 실험체에 비해 평균적으로 강도면에서 1.37배, 연성도면에서 9.16배 증가하였다. 이는 래티스 철근이 무량판 구조의 전단보강재로서 전단강도와 연성도 측면에서 매우 효과적인 보강방법임을 입증하고 있으며, 현재 미국에서 접합부 전단보강재로 널리 사용되고 있는 스터드레일 전단보강보다 연성능력이 훨씬 우수한 것으로 나타났다. 또한 실험결과에 근거하여 래티스전단보강의 강도평가방법을 개발하였다.

• Steel and Composite Structures
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• 제19권5호
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• pp.1321-1331
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• 2015

A square steel sandwich plate with lattice corrugated core is explored for damping improvement. A range of damping materials are filled inside the openings provided by the corrugated core, or are applied on the surfaces of the facesheets. The dynamic properties such as natural frequency and damping factor are experimentally measured for the sandwich plate with each filling solution. The relative performance of each insertion is compared in terms of damping capacity and added mass.

• 한국구조물진단유지관리공학회 논문집
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• 제27권1호
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• pp.95-102
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• 2023

본 연구에서는 다양한 래티스 단부 지점조건을 갖는 철선일체형 데크플레이트의 구조성능을 유한요소해석을 통하여 평가하였다. 해석결과, 래티스 단부에서 풋의 위치가 지점부 구조부재 위에 위치하는 경우가 그렇지 않은 경우에 비해 시스템 강성이 더 큰 것으로 나타났다. 또한 래티스 풋이 지점부에 위치하는 경우, 단부 직봉이 전체 데크플레이트 시스템의 강성과 강도에 미치는 영향은 무시할 정도로 작았다. 특히 래티스 풋의 길이가 40mm 보다 작지 않을 때에는 단부 직봉이 설치되지 않아도 무방한 것으로 평가되었다. 래티스 단부 지지형상이 데크플레이트 시스템의 최대 하중저항 성능에 미치는 영향은 크지 않은 것으로 조사되었고, 시스템의 파괴모드는 설계의도에 따라 데크플레이트 중앙에서 상부 주철근의 좌굴, 래티스 단부 좌굴, 또는 이들의 조합으로 나타났다.

• 한국공간구조학회논문집
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• 제20권2호
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• pp.31-38
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• 2020

U-flanged truss beam is composed of u-shaped upper steel flange, lower steel plate of 8mm or more thickness, and connecting lattice bars. Upper flange and lower plate are connected by the diagonal lattice bars welded on the upper and lower sides. In this study, the details of delayed buckling of lattice members were developed through reinforcement of the end section, in order to improve structural capacity of U-flanged Truss Steel Beam. To verify the effects of these details, the simple beam experiment was conducted. The maximum capacity of all the specimens were determined by the buckling of the lattice. The vertical reinforced details of the ends with steel plates, rather than the details reinforced with steel bars, are confirmed to be a valid method for enhancing the structural capacity of the U-flanged Truss beam. In addition, U-flanged Truss Steel Beam with reinforced endings with steel plates can exhibit sufficient capacity of the lattice buckling by the formulae according to Korean Building Code (KBC, 2016) and Eurocode 3.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 가을 학술발표회 논문집
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• pp.587-590
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• 2003

In flat-plate floors, slab-column connections are broken down with a brittle shear failure. And it can cause the collapse of the whole structures. Thus, the proper method of shear reinforcement in flat plate-column connections must be required. The objective of this study is to compare shear reinforcement specimens using lattice bars to no shear reinforcement specimens in view of shear strength and ductility of the flat plate-column connections. The test results have shown that shear reinforcement specimens varying $\rho$, $b_0$/d and $C_1$/$C_2$ increase in shear strength by 36.85% and in ductility by 9.16 for no shear reinforcement specimens on the average. This results confirm the effectiveness of this type of shear reinforcement in improving shear strength and ductility.

• 한국지반공학회지:지반
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• 제13권4호
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• pp.163-176
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• 1997

NATM 터널에서 강지보재로 이용되어지는 H형강은 그 동안 많은 단점이 지적되어 왔으며, 그 중 하나는 숏크리트 타설시 H형강 flange 배면에 발생하는 공동으로 인하여 숏크리트를 포함 한 초기지보재의 하중지지력 저감을 들 수 있다. 이와 같은 단점을 보완하기 위하여 유럽의 많은 나라에서는 H형강 지보재와 같은 plate girder 형태의 지보재에 비하여 많은 장점을 가진 fat twice girder(격자지보)라는 지보재를 개발하여 현장에 적용하고 있다. 터널 굴착시 격자지보를 초기 지보재로서 효율적으로 사용하기 위해서는 하중지지력에 대한 심도있는 연구가 필요하다. 따라서 본 연구에서는 격자지보의 하중지지력 평가 및 검증의 일환으로 격자지보에 대한 굴곡시험과 압축시험을 수행하였다. 그 결과 격자지보는 H형강 지보재에 비하여 우수한 하중지지력을 보유하는 것으로 나타났으며, 따라서 터널 시공시 지보재로서 효율적으로 적용할 수 있을 것으로 판단된다.

• 한국공간구조학회논문집
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• 제18권4호
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• pp.113-121
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• 2018

U-flanged truss beam is composed of u-shaped upper steel flange, lower steel plate of 8mm or more thickness, and connecting lattice bars. Upper flange and lower plate are connected by the diagonal lattice bars welded on the upper and lower sides. In this study the structural experiments on the U-flanged truss beams with various shapes of upper flange were performed, and the flexural and shear capacities of U-flanged truss beam in the construction stage were evaluated. The principal test parameters were the shape of upper flange and the alignment space of diagonal lattice bars. In all the test specimens, the peak loads were determined by the buckling of lattice bar regardless of the upper flange shape. The test results have shown that the buckling of lattice bar is very important design factor and there is no need to reinforce the basic u-shaped upper flange. However, the early lattice buckling occurred in the truss beam with upper steel bars because of the insufficient strength and stiffness of upper chord, and the reinforcement in the upper chord is necessary. The formulae of Eurocode 3 (2005) have presented more exact evaluations of lattice buckling load than those of KBC 2016.