• Title, Summary, Keyword: Composite load

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Experimental tests on biaxially loaded concrete-encased composite columns

  • Tokgoz, Serkan;Dundar, Cengiz
    • Steel and Composite Structures
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    • v.8 no.5
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    • pp.423-438
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    • 2008
  • This paper reports an experimental investigation of the behaviour of concrete-encased composite columns subjected to short-term axial load and biaxial bending. In the study, six square and four L-shaped cross section of both short and slender composite column specimens were constructed and tested to examine the load-deflection behaviour and to obtain load carrying capacities. The main variables in the tests were considered as eccentricity of applied axial load, concrete compressive strength, cross section, and slenderness effect. A theoretical procedure considering the nonlinear behaviour of the materials is proposed for determination of the behaviour of eccentrically loaded short and slender composite columns. Two approaches are taken into account to describe the flexural rigidity (EI) used in the analysis of slender composite columns. Observed failure mode and experimental and theoretical load-deflection behaviour of the specimens are presented in the paper. The composite column specimens and also some composite columns available in the literature have been analysed and found to be in good agreement with the test results.

Development of Composite Load Models of Power Systems using On-line Measurement Data

  • Choi Byoung-Kon;Chiang Hsiao Dong;Li Yinhong;Chen Yung Tien;Huang Der Hua;Lauby Mark G.
    • Journal of Electrical Engineering and Technology
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    • v.1 no.2
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    • pp.161-169
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    • 2006
  • Load representation has a significant impact on power system analysis and control results. In this paper, composite load models are developed based on on-line measurement data from a practical power system. Three types of static-dynamic load models are derived: general ZIP-induction motor model, Exponential-induction motor model and Z-induction motor model. For the dynamic induction motor model, two different third-order induction motor models are studied. The performances in modeling real and reactive power behaviors by composite load models are compared with other dynamic load models in terms of relative mismatch error. In addition, numerical consideration of ill-conditioned parameters is addressed based on trajectory sensitivity. Numerical studies indicate that the developed composite load models can accurately capture the dynamic behaviors of loads during disturbance.

An experimental study on structural behaviour of the MMA double wide flanged GFRP pipe composite structures (II) (MMA 이중 플랜지를 갖는 GFRP 복합관 구조거동에 관한 실험 연구 (II))

  • Ji, Hyo-Seon;Mamdouh, El-Badry
    • Journal of the Korean Society for Advanced Composite Structures
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    • v.6 no.3
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    • pp.50-61
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    • 2015
  • This paper presents on the structural behavior of the the methyl methacrylate monomer (MMA) double wide flanged the glass fiber-reinforced polymer(GFRP) pipe composite structures for the manhole raise. The evaluation of structural performance on this composite structure was conducted by the axial load, fatigue load, and ultimate load test. The assessment indicates that the MMA double wide flanged GFRP pipe composite structures was confirmed safety, durability and reliability in result as expected. It was found that this composite structure was able to short working times to around 30-50% and construction costs to around 10-23% with compare other construction methods. Also, environmental pollution and civil complaints will be prevented because there will be no longer any noises, vibrations, dust, or construction wastes.

Buckling behavior of composite cylindrical shells with cutout considering geometric imperfection

  • Heidari-Rarani, M.;Kharratzadeh, M.
    • Steel and Composite Structures
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    • v.30 no.4
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    • pp.305-313
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    • 2019
  • Creating different cutout shapes in order to make doors and windows, reduce the structural weight or implement various mechanisms increases the likelihood of buckling in thin-walled structures. In this study, the effect of cutout shape and geometric imperfection (GI) is simultaneously investigated on the critical buckling load and knock-down factor (KDF) of composite cylindrical shells. The GI is modeled using single perturbation load approach (SPLA). First, in order to assess the finite element model, the critical buckling load of a composite shell without cutout obtained by SPLA is compared with the experimental results available in the literature. Then, the effect of different shapes of cutout such as circular, elliptic and square, and perturbation load imperfection (PLI) is investigated on the buckling behavior of cylindrical shells. Results show that the critical buckling load of a shell without cutout decreases by increasing the PLI, whereas increasing the PLI does not have a great impact on the critical buckling load in the presence of cutout imperfection. Increasing the cutout area reduces the effect of the PLI, which results in an increase in the KDF.

Measurement-based Estimation of the Composite Load Model Parameters

  • Kim, Byoung-Ho;Kim, Hong-Rae
    • Journal of Electrical Engineering and Technology
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    • v.7 no.6
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    • pp.845-851
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    • 2012
  • Power system loads have a significant impact on a system. Although it is difficult to precisely describe loads in a mathematical model, accurately modeling them is important for a system analysis. The traditional load modeling method is based on the load components of a bus. Recently, the load modeling method based on measurements from a system has been introduced and developed by researchers. The two major components of a load modeling problem are determining the mathematical model for the target system and estimating the parameters of the determined model. We use the composite load model, which has both static and dynamic load characteristics. The ZIP model and the induction motor model are used for the static and dynamic load models, respectively. In this work, we propose the measurement-based parameter estimation method for the composite load model. The test system and related measurements are obtained using transient security assessment tool(TSAT) simulation program and PSS/E. The parameter estimation is then verified using these measurements. Cases are tested and verified using the sample system and its related measurements.

Refined Decoupled Stress Analysis for Thermo-piezoelectric Composite Plate (열-전기-기계 하중에서의 복합재 평판의 응력해석)

  • 오진호;조맹효
    • Proceedings of the Korean Society For Composite Materials Conference
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    • pp.46-49
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    • 2000
  • A decoupled thermo-~lezoelectric-mechanical model of composite laminates with surface bonded piezoelectric actuators, subjected to externally applied load, temperature change load, electric field load is developed. The governing differential equations are obtained by applying the principle of free energy and variational techniques. A higher order zigzag theory displacement field is employed to accurately capture the transverse shear and normal effects in laminated composite plates of arbitrary thickness.

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A Study on the Long-term Mechanical Properties Under Static and Cyclic State of Composite Insulators for Transmission Lines (송전용 고분자 애자의 정적 및 동적인 상태에서 장기 기계적 특성 연구)

  • Kim, S.Y.;Kim, Y.S.;Hong, J.Y.;Park, W.K.
    • Proceedings of the KIEE Conference
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    • pp.869-871
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    • 1998
  • The extensive use of composite insulators for transmission lines can ultimately be justified only on long-term qualification tests. The actual load working on the insulator in the field is not static load but cyclic load. So in this paper, we discussed an examination of aging degradation by mechanical performance of composite insulators under static tension load and cyclic tension load. and also described useful approaches for analyzing their long term performance so as to develop reliable composite insulators. The static and cyclic tension load-time test data were examined by Weibull distribution for their capability of presuming long term performance. It was found that cyclic tension loads were more severe than static tension loads. The results also indicate that it may be relevant for an user to select composite insulators on basis of their performance under cyclic tension loads than static tension loads.

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Multi-Objective Design Optimization of Composite Stiffened Panel Using Response Surface Methodology

  • Murugesan, Mohanraj;Kang, Beom-Soo;Lee, Kyunghoon
    • Composites Research
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    • v.28 no.5
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    • pp.297-310
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    • 2015
  • This study aims to develop efficient composite laminates for buckling load enhancement, interlaminar shear stress minimization, and weight reduction. This goal is achieved through cover-skin lay-ups around skins and stiffeners, which amplify bending stiffness and defer delamination by means of effective stress distribution. The design problem is formulated as multi-objective optimization that maximizes buckling load capability while minimizing both maximum out-of-plane shear stress and panel weight. For efficient optimization, response surface methodology is employed for buckling load, two out-of-plane shear stresses, and panel weight with respect to one ply thickness, six fiber orientations of a skin, and four stiffener heights. Numerical results show that skin-covered composite stiffened panels can be devised for maximum buckling load and minimum interlaminar shear stresses under compressive load. In addition, the effects of different material properties are investigated and compared. The obtained results reveal that the composite stiffened panel with Kevlar material is the most effective design.

Estimation of Dynamic Response of Advanced Composite Material Decks for Bridges Application under Various Vehicle Driving Velocities (복합재료 교량 바닥판의 주행속도에 따른 동적응답 평가)

  • 천경식;장석윤
    • Composites Research
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    • v.16 no.6
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    • pp.23-32
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    • 2003
  • Applications of advanced composite material in construction field are tending upwards and development of all composite material bridges is making progress rapidly in home and abroad due to their high strength to weight ratio. This paper formulated the dynamic responses of the laminated composite structures subjected to moving load and analyzed the various dynamic behaviors using the finite element method. The nondimensionalized natural frequencies of a simply supported square-laminated composite plate are considered for verifications. Mode superposition and Newmark direct integration method are applied for moving load analysis. For structural models, dynamic magnification factor calculated for various velocities of the moving load and displacements characteristics of laminated composite structures due to the moving load are investigated theoretically Numerical results are presented to study the effects of lamination scheme, stacking sequence, and fiber angle for laminated composite structures during moving load. The various results on moving load and lamination through numerical analysis will present an important basic data for development and grasp the behavior of all composite material bridges.

Partially encased composite columns using fiber reinforced concrete: experimental study

  • Pereira, Margot F.;De Nardin, Silvana;El. Debs, Ana L.H.C.
    • Steel and Composite Structures
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    • v.34 no.6
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    • pp.909-927
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    • 2020
  • This paper addresses the results of an experimental study involving 10 partially encased composite columns under concentric and eccentric compressive loads. Parameters such as slenderness ratio, ordinary reinforced concrete and fiber reinforced concrete, load eccentricity and bending axis were investigated. The specimens were tested to investigate the effects of replacing the ordinary reinforced concrete by fiber reinforced concrete on the load capacity and behavior of short and slender composite columns. Various characteristics such as load capacity, axial strains behavior, stiffness, strains on steel and concrete and failure mode are discussed. The main conclusions that may be drawn from all the test results is that the behavior and ultimate load are rather sensitive to the slenderness of the columns and to the eccentricity of loading, specially the bending axis. Experimental results also indicate that replacing the ordinary reinforced concrete by steel fiber reinforced concrete has no considerable effects on the load capacity and behavior of the short and slender columns and the proposed replacement presented very good results.