• Title, Summary, Keyword: nonlinear behaviour

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Performance analysis of a detailed FE modelling strategy to simulate the behaviour of masonry-infilled RC frames under cyclic loading

  • Mohamed, Hossameldeen M.;Romao, Xavier
    • Earthquakes and Structures
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    • v.14 no.6
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    • pp.551-565
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    • 2018
  • Experimental testing is considered the most realistic approach to obtain a detailed representation of the nonlinear behaviour of masonry-infilled reinforced concrete (RC) structures. Among other applications, these tests can be used to calibrate the properties of numerical models such as simplified macro-models (e.g., strut-type models) representing the masonry infill behaviour. Since the significant cost of experimental tests limits their widespread use, alternative approaches need to be established to obtain adequate data to validate the referred simplified models. The proposed paper introduces a detailed finite element modelling strategy that can be used as an alternative to experimental tests to represent the behaviour of masonry-infilled RC frames under earthquake loading. Several examples of RC infilled frames with different infill configurations and properties subjected to cyclic loading are analysed using the proposed modelling approach. The comparison between numerical and experimental results shows that the numerical models capture the overall nonlinear behaviour of the physical specimens with adequate accuracy, predicting their monotonic stiffness, strength and several failure mechanisms.

Improved nonlinear modelling approach of simply supported PC slab under free blast load using RHT model

  • Rashad, Mohamed;Yang, T.Y.
    • Computers and Concrete
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    • v.23 no.2
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    • pp.121-131
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    • 2019
  • Due to the heterogeneity nature of the concrete, it is difficult to simulate the hyperdynamic behaviour and crack trajectory of concrete material when subjected to explosion loads. In this paper, a 3D nonlinear numerical study was conducted to simulate the hyperdynamic behaviour of concrete under various loading conditions using Riedel-Hiermaier-Thoma (RHT) model. Detailed calibration was conducted to identify the optimal parameters for the RHT model on the material level. For the component level, the calibrated RHT parameters were used to simulate the failure behaviour of plain concrete (PC) slab under free air blast load. The response was compared with an available experimental result. The results show the proposed numerical model can accurately simulate the crack trajectory and the failure mode of the PC slab under free air blast load.

The soil effect on the seismic behaviour of reinforced concrete buildings

  • Yon, Burak;Calayir, Yusuf
    • Earthquakes and Structures
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    • v.8 no.1
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    • pp.133-152
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    • 2015
  • This paper investigates the soil effect on seismic behaviour of reinforced concrete (RC) buildings by using the spread plastic hinge model which includes material and geometric nonlinearity of the structural members. Therefore, typical reinforced concrete frame buildings are selected and nonlinear dynamic time history analyses and pushover analyses are performed. Three earthquake acceleration records are selected for nonlinear dynamic time history analyses. These records are adjusted to be compatible with the design spectrum defined in Turkish Seismic Code. Interstory drifts and damages of selected buildings are compared according to local soil classes. Also, capacity curves of these buildings are compared with maximum responses obtained from nonlinear dynamic time history analyses. The results show that, soil class influences the seismic behaviour of reinforced concrete buildings, significantly.

Assessing 3D seismic damage performance of a CFR dam considering various reservoir heights

  • Karalar, Memduh;Cavusli, Murat
    • Earthquakes and Structures
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    • v.16 no.2
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    • pp.221-234
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    • 2019
  • Today, many important concrete face rockfill dams (CFRDs) have been built on the world, and some of these important structures are located on the strong seismic regions. In this reason, examination and monitoring of these water construction's seismic behaviour is very important for the safety and future of these dams. In this study, the nonlinear seismic behaviour of Ilısu CFR dam which was built in Turkey in 2017, is investigated for various reservoir water heights taking into account 1995 Kobe near-fault and far-fault ground motions. Three dimensional (3D) finite difference model of the dam is created using the FLAC3D software that is based on the finite difference method. The most suitable mesh range for the 3D model is chosen to achieve the realistic numerical results. Mohr-Coulomb nonlinear material model is used for the rockfill materials and foundation in the seismic analyses. Moreover, Drucker-Prager nonlinear material model is considered for the concrete slab to represent the nonlinearity of the concrete. The dam body, foundation and concrete slab constantly interact during the lifetime of the CFRDs. Therefore, the special interface elements are defined between the dam body-concrete slab and dam body-foundation due to represent the interaction condition in the 3D model. Free field boundary condition that was used rarely for the nonlinear seismic analyses, is considered for the lateral boundaries of the model. In addition, quiet artificial boundary condition that is special boundary condition for the rigid foundation in the earthquake analyses, is used for the bottom of the foundation. The hysteric damping coefficients are separately calculated for all of the materials. These special damping values is defined to the FLAC3D software using the special fish functions to capture the effects of the variation of the modulus and damping ratio with the dynamic shear-strain magnitude. Total 4 different reservoir water heights are taken into account in the seismic analyses. These water heights are empty reservoir, 50 m, 100 m and 130 m (full reservoir), respectively. In the nonlinear seismic analyses, near-fault and far-fault ground motions of 1995 Kobe earthquake are used. According to the numerical analyses, horizontal displacements, vertical displacements and principal stresses for 4 various reservoir water heights are evaluated in detail. Moreover, these results are compared for the near-fault and far-faults earthquakes. The nonlinear seismic analysis results indicate that as the reservoir height increases, the nonlinear seismic behaviour of the dam clearly changes. Each water height has different seismic effects on the earthquake behaviour of Ilısu CFR dam. In addition, it is obviously seen that near-fault earthquakes and far field earthquakes create different nonlinear seismic damages on the nonlinear earthquake behaviour of the dam.

Explicit incremental matrices for the postbuckling analysis of thin plates with small initial curvature

  • Jayachandran, S. Arul;Gopalakrishnan, S.;Narayanan, R.
    • Structural Engineering and Mechanics
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    • v.12 no.3
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    • pp.283-295
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    • 2001
  • The postbuckling behaviour of thin plates is an important phenomenon in the design of thin plated structures. In reality plates possess small imperfections and the behaviour of such imperfect plates is of great interest. To numerically study the postbuckling behaviour of imperfect plates explicit incremental or secant matrices have been presented in this paper. These matrices can be used in combination with any thin plate element. The secant matrices are shown to be very accurate in tracing the postbuckling behaviour of thin plates.

A Study on the Geometric Nonlinear Behaviour of Ship Plate by Energy Method (에너지법에 의한 선체판의 기하학적 비선형거동에 관한 연구)

  • Jae-Yong Ko
    • Journal of the Society of Naval Architects of Korea
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    • v.36 no.2
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    • pp.94-104
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    • 1999
  • Plate buckling is very important design criteria when the ship is composed of high tensile steel plates. In general, the plate element contributes to inplane stiffness against the action of inplane load. If the inplane stiffness of the plating decreases due to buckling including the secondary buckling, the flexural rigidity of the cross section of a ship's hull also decreases. In these cases, the precise estimation of plate's behaviour after buckling is necessary, and geometric nonlinear behaviour of isolated plates is required for structural system analysis. In this connection, the author investigated the geometric nonlinear behaviour of simply supported rectangular plates under uniaxial compression in the longitudinal direction in which the principle of minimum potential energy method is employed. Based on the energy method, elastic large deflection analysis of isolated palate is performed and simple expression are derived to discuss the bifurcation paint type buckling and limit point type buckling.

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A Study on the Analysis of Steel Bracing Behaviour Subjected to Cyclic loads (반복하중을 받는 강재 브레이싱의 거동에 관한 해석적 연구)

  • 구민세;김병석;김일곤
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.44-49
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    • 1989
  • The primary purpose of using bracings is to improve tile lateral rigidity of main structural system, i.e., columns and beams, by reinforcing them with much smaller members. Conventional design methods consider bracings as tension-only mambers, since difficulties arise in the analysis to consider the P - effects and post-buckling behaviour of the bracing members. This is particulary true for X-bracings. Recently, however, both analytical and experimental studies have been conducted to investigate the more precise and real behaviour of bracing members, especially for the nonlinear un plastic behaviour under cyclic loads. In this study, an analytical model is proposed to investigate the nonlinear behavior of steel bracing members subjected to cyclic loads. Results of tile analysis were compared with previous experimental results, and good agreements were obtained between these results.

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Numerical Simulation of Dynamic Behaviour of a Gauge-changeable Freight Wagon (궤간가변화차의 동특성 수치해석)

  • Jang Seung-Ho;Lee Il-Seung
    • Journal of the Korean Society for Railway
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    • v.9 no.4
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    • pp.461-466
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    • 2006
  • In order to transport cargo rapidly and safely from the trans-Korean railway to the trans-Siberian railway having a different gauge, a gauge-changeable freight wagon can be used. Because the wagon is expected to run in South Korea, North Korea and Russia, it should have good dynamic performance in these railways. In this paper, the dynamic characteristics of a gauge-changeable freight wagon was analyzed numerically using ADAMS/Rail in each condition of the railways having different gauges and rail profiles. The wagon makes use of load sensitive friction damping and has highly nonlinear behaviour, which is modeled in detail as the full nonlinear dynamic model. It is shown that the running behaviour of the wagon is sensitive to changes in the rail gauge and profiles, however the assessment quantities from the point of view of safety, track fatigue and running behaviour are less than the limit valves.

Nonlinear analysis and tests of steel-fiber concrete beams in torsion

  • Karayannis, Chris G.
    • Structural Engineering and Mechanics
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    • v.9 no.4
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    • pp.323-338
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    • 2000
  • An analytical approach for the prediction of the behaviour of steel-fiber reinforced concrete beams subjected to torsion is described. The analysis method employs a special stress-strain model with a non-linear post cracking branch for the material behaviour in tension. Predictions of this model for the behaviour of steel-fiber concrete in direct tension are also presented and compared with results from tests conducted for this reason. Further in this work, the validation of the proposed torsional analysis by providing comparisons between experimental curves and analytical predictions, is attempted. For this purpose a series of 10 steel-fiber concrete beams with various cross-sections and steel-fiber volume fractions tested in pure torsion, are reported here. Furthermore, experimental information compiled from works around the world are also used in an attempt to establish the validity of the described approach based on test results of a broad range of studies. From these comparisons it is demonstrated that the proposed analysis describes well the behaviour of steel-fiber concrete in pure torsion even in the case of elements with non-rectangular cross-sections.

Effects of confinement reinforcement and concrete strength on nonlinear behaviour of RC buildings

  • Yon, Burak;Calayir, Yusuf
    • Computers and Concrete
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    • v.14 no.3
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    • pp.279-297
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    • 2014
  • This paper investigates the effects of confinement reinforcement and concrete strength on nonlinear behaviour of reinforced concrete buildings (RC). For numerical application, an eleven-storey and four bays reinforced concrete frame building is selected. Nonlinear incremental static (pushover) analyses of the building are performed according to various concrete strengths and whether appropriate confinement reinforcement, which defined in Turkish seismic code, exists or not at structural elements. In nonlinear analysis, distributed plastic hinge model is used. As a result of analyses, capacity curves of the frame building and moment-rotation curves at lower end sections of ground floor columns are determined. These results are compared with each other according to concrete strength and whether appropriate confinement reinforcement exists or not, respectively. According to results, it is seen that confinement reinforcement is important factor for increasing of building capacity and decreasing of rotations at structural elements.