• Steel and Composite Structures
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• 제19권3호
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• pp.635-659
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• 2015

In this study, natural frequency analysis of a large deflected cantilever laminated composite beam fixed at both ends, which forms the case of a pre-stressed curved beam, is investigated. The laminated beam is considered to have symmetric and asymmetric lay-ups and the effective flexural modulus of the beam is used in the analysis. In order to obtain the pre-stressed composite curved beam case, an external vertical concentrated load is applied at the free end of a cantilever laminated composite beam and then the loading point of the deflected beam is fixed. The non-linear deflection curve of the flexible beam undergoing large deflection is obtained by the Reversion Method. The curved laminated composite beam is modeled by using the Finite Element Method with a straight-beam element approach. The effects of orientation angle and vertical load on the natural frequency parameter for the first four modes are examined and the results obtained are given in graphics. It has been found that the effect of the load parameter, which forms the curved laminated beam, on the natural frequency parameter, almost disappears after a certain value of the load parameter. This certain value differs for each laminated curved beam and each vibration mode.

• 한국전산구조공학회논문집
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• 제20권2호
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• pp.207-216
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• 2007

본 논문에서는 볼트로 체결된 강재 조립 합성보의 휨거동에 대한 유한요소해석을 통하여 휨거동 특성을 분석하였다. 두개의 강재보가 볼트로 체결되어 횡하중을 받을 때 발생하는 볼트의 합성효과, 강판사이의 마찰특성을 고려하였다. 체결에 사용된 볼트의 갯수 및 마찰계수의 변화에 따른 변위, 휨응력 그리고 전단응력을 쉘 요소를 사용한 유한요소해석에 의해 계산하였다. 이런 결과들은 완전 비합성보, 부분 합성보와 완전 합성보의 해석치와 비교되었다. 해석결과 합성보의 거동은 강재의 마찰보다 볼트의 갯수로 표현되는 합성률에 크게 영향을 받았다. 합성률이 $50{\sim}60%$에 도달할 때 합성보의 거동은 완전 합성보와 유사함을 보였다.

• Steel and Composite Structures
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• 제46권4호
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• pp.539-551
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• 2023

In order to study the fire resistance of castellated composite beams with ortho-hexagonal holes and different beam-end restraints, temperature rise tests with constant load were conducted on full-scale castellated composite beams with ortho-hexagonal holes and hinge or rigid joint constraints to investigate the temperature distribution, displacement changes and failure patterns of castellated composite beams with two different beam-end constraints during the whole course of fire. The results show that (1) During the fire, the axial pressure and horizontal expansion deformation generated in the rigid joint constrained composite beam were larger than those in the hinge joint constrained castellated composite beam, and their maximum horizontal expansion displacements were 30.2 mm and 17.8 mm, respectively. (2) After the fire, the cracks on the slab surface of the castellated composite beam with rigid joint constraint were more complicated than hinge restraint, and the failure more serious; the lower flange and web at the ends of the castellated steal beams with hinge and rigid joint constraint produced serious local buckling, and the angles of the ortho-hexagonal holes at the support cracked; the welds at both ends of the castellated composite beam with rigid joint constraint cracked. (3) Based on the simplified calculation method of solid-web composite beam, considering the effect of holes on the web, this paper calculated the axial force and displacement of the beam-end constrained castellated composite beams under fire. The calculation results agreed well with the test results.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 1999년도 추계학술발표대회 논문집
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• pp.5-14
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• 1999

Free vibration characteristics of a cantilevered laminated composite beam with multiple non-propagating transverse open cracks are investigated. In the present analysis a special ply-angle distribution referred to as asymmetric stiffness configuration inducing the elastic coupling between chord-wise bending and extension is considered. The multiple open cracks are modelled as equivalent rotational springs whose spring constants are calculated based on the fracture mechanics of composite material structures. Governing equations of a composite beam with open cracks are derived via Hamilton's Principle and Timoshenko beam theory encompassing transverse shear and rotary inertia effect is adopted. The effects of various parameters such as the ply angle, fiber volume fraction, crack numbers, crack positions and crack depthes on the free vibration characteristics of the beam with multiple cracks are highlighted. The numerical results show that the existence of the multiple cracks in an anisotropic composite beam affects the free vibration characteristics in a more complex fashion compared with the beam with a single crack.

• Steel and Composite Structures
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• 제21권3호
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• pp.679-688
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• 2016

Structural design of a composite beam is influenced by two main factors, strength and ductility. For the design to be effective for a composite beam, say an RC slab and a steel I beam, the shear strength of the composite beam and ductility have to carefully estimate with the help of displacements between the two members. In this investigation the shear strengths of steel-concrete composite beams was analyzed based on the respective variable parameters. The methodology used by ANFIS (Adaptive Neuro Fuzzy Inference System) has been adopted for this purpose. The detection of the predominant factors affecting the shear strength steel-concrete composite beam was achieved by use of ANFIS process for variable selection. The results show that concrete compression strength has the highest influence on the shear strength capacity of composite beam.

• Structural Engineering and Mechanics
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• 제67권4호
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• pp.337-346
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• 2018

The purpose of this study is to investigate thermal post-buckling analysis of a laminated composite beam subjected under uniform temperature rising with temperature dependent physical properties. The beam is pinned at both ends and immovable ends. Under temperature rising, thermal buckling and post-buckling phenomena occurs with immovable ends of the beam. In the nonlinear kinematic model of the post-buckling problem, total Lagrangian approach is used in conjunction with the Timoshenko beam theory. Also, material properties of the laminated composite beam are temperature dependent: that is the coefficients of the governing equations are not constant. In the solution of the nonlinear problem, incremental displacement-based finite element method is used with Newton-Raphson iteration method. The effects of the fibber orientation angles, the stacking sequence of laminates and temperature rising on the post-buckling deflections, configurations and critical buckling temperatures of the composite laminated beam are illustrated and discussed in the numerical results. Also, the differences between temperature dependent and independent physical properties are investigated for post-buckling responses of laminated composite beams.

• Structural Engineering and Mechanics
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• 제85권5호
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• pp.573-592
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• 2023

This paper presents a careful theoretical investigation into interfacial stresses in composite aluminum-slab reinforced concrete beam bonded by a prestressed hybrid carbon-glass composite material. The model is based on equilibrium and deformations compatibility requirements in and all parts of the strengthened beam, i.e., the aluminum beam, the slab reinforced concrete, the hybrid carbon-glass composite plate and the adhesive layer. The theoretical predictions are compared with other existing solutions. Numerical results from the present analysis are presented both to demonstrate the advantages of the present solution over existing ones and to illustrate the main characteristics of interfacial stress distributions. It is shown that the stresses at the interface are influenced by the material and geometry parameters of the composite beam. This research is helpful for the understanding on mechanical behaviour of the interface and design of the hybrid structures.

• Steel and Composite Structures
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• 제26권6호
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• pp.733-743
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• 2018

This paper presents post-buckling responses of a simply supported laminated composite beam subjected to a non-follower axially compression loads. In the nonlinear kinematic model of the laminated beam, total Lagrangian approach is used in conjunction with the Timoshenko beam theory. In the solution of the nonlinear problem, incremental displacement-based finite element method is used with Newton-Raphson iteration method. There is no restriction on the magnitudes of deflections and rotations in contradistinction to von-Karman strain displacement relations of the beam. The distinctive feature of this study is post-buckling analysis of Timoshenko Laminated beams full geometric non-linearity and by using finite element method. The effects of the fibber orientation angles and the stacking sequence of laminates on the post-buckling deflections, configurations and stresses of the composite laminated beam are illustrated and discussed in the numerical results. Numerical results show that the above-mentioned effects play a very important role on the post-buckling responses of the laminated composite beams.

• 국제강구조저널
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• 제18권5호
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• pp.1772-1783
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• 2018

Nowadays, the researches about composite structure system are being implemented in various fields, and many steel structures are designed based on that. In this study, the bending and seismic performance of the newly developed high-performance cold forming composite beam are evaluated by several experiments. As a result of the bending performance test, the bending moment of beam was increased stably depending on the depth and plate thickness of beam, and it is considered that the bending moment can be evaluated by the equation of a composite beam design. As a result of the seismic performance test, it was verified that sufficient seismic performance was obtained despite the increase of a negative moment rebar and depth of beam. In addition, the nominal bending moment has obtained the strength above the plastic bending moment, and also the plastic rotation angle has satisfied the requirement of composite intermediate moment frame.

• 한국강구조학회 논문집
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• 제16권2호통권69호
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• pp.225-233
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• 2004

일반적인 합성보는 콘크리트 슬래브와 H형강 철골보 사이에 작용하는 수평전단력을 쉬어 코넥터로 긴결하여 휨 내력 및 강성을 증가시킨 구조이다. 본 연구에서 제안한 TSC 구조는 H형강 대신 U형 철골을 사용하고 그 속에 콘크리트를 채운 새로운 형태의 합성보 시스템으로 실험을 통하여 구조특성을 평가 분석 하였다. 또한 실험결과를 통해 T형 합성보(이하 TSC 보라 칭함)의 구조설계 및 시공에 필요한 기초 자료를 제시하고자 한다.