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1

Finite beam element with 22 DOF for curved composite box girders considering torsion, distortion, and biaxial slip

Zhu Li, Wang Jia-Ji, Li Ming-Jie, Chen Chao, Wang Guang-Ming

Archives of Civil and Mechanical Engineering

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2020

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Vol. 20, no. 4

16--34

EN

Experimental and numerical study on the mechanical performance of curved steel–concrete composite box girders is reported in this research. First, this research establishes a theoretical model for curved composite girders with 11° of freedoms (DOFs) for each node. The DOFs include the longitudinal displacement, transverse displacement, deflection, torsion angle, warping angle, and interface biaxial slip between steel and concrete. Based on the virtual work theorem, the equilibrium function, the stiffness matrix, the node displacement matrix and the external load matrix are proposed for the curved composite girders using the FE spatial discretization. Second, the authors conduct an experimental program on three large-scale curved composite girders with various interface shear connectors and central angles. The comparison between the developed finite beam element, the elaborate FE model and the test results indicates the developed finite beam element has an adequate level of accuracy in predicting the deflection, the torsion angle and the axial strain distribution of test specimens. Third, based on the developed finite beam element model, the effect of initial curvature, number of diaphragms, and the interface connector stiffness on the curved composite girder is examined. The simulation results showed that the initial curvature significantly contributes to the displacement and stress of composite girders. Applying more diaphragms can notably reduce the distortion angle and distortion displacement. The interface shear connector stiffness has a significant influence on the curved composite girder. With the increasing shear connector stiffness, the displacement and stress of curved composite girders decrease notably. Based on the parametric analyses, it is recommended to limit the central angle of simply supported composite girder below 45°, to apply an adequate number of diaphragms, and to design curved composite girders as fully shear connection specimens.

2

Zastosowanie teorii belek w zastępczym modelu ustroju kratownicowego

Balcerowiak Sebastian, Czajkowski Jakub, Lorenc Wojciech, Sęk Radosław

Inżynieria i Budownictwo

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2019

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R. 75, nr 7-8

339--342

PL

Przedstawiono koncepcję zastępczego modelu ustroju kratownicowego wraz z objaśnieniem kluczowych kwestii uwzględniania sztywności postaciowej oraz skrętnej. Podjęto rozważania dotyczące numerycznego modelowania konstrukcji, uwzględniając zagadnienia praktyczne i naukowe.

EN

The concept of a bar model of the truss system is presented along with an explanation of the key issues of taking into account of the shear and torsional stiffness in the substitute model. A discussion was made on numerical modelling of structures considering both engineering and scientific issues.

3

Interlaminar cracking resistance of nonhomogeneous composite beams

Dadej K., Bieniaś J., Surowska B.

Composites Theory and Practice

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2017

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R. 17, nr 3

144--148

EN

This article is devoted to interlaminar cracking research on carbon multidirectional fibrous-epoxy composites. Composite beams with 0°/0° 0°/45° and 0°/90° interfaces were subjected to double cantilever beam tests whereby force-crack opening displacement curves were determined. Additionally, crack length observations were conducted in order to determine the crack resistance curves of multidirectional composites. On the basis of the performed tests, it was found that the critical strain energy release rate for crack initiation is size independent of the material configuration. On the other hand, the fiber orientation is crucial to the critical strain energy release rate for crack propagation.

PL

Artykuł dotyczy badań odporności na pękanie wielokierunkowych kompozytów epoksydowo-włóknistych na bazie włókien węglowych. Belki kompozytowe z interfejsami 0°/0° 0°/45° oraz 0°/90° zostały zbadane za pomocą metody Double Cantilever Beam, w których wyznaczono charakterystyki siła - wielkość rozwarcia szczeliny. Dodatkowo prowadzono obserwacje długości pęknięcia w celu wyznaczenia krzywych odporności na pękanie kompozytów wielokierunkowych. Na podstawie przeprowadzonych badań stwierdzono, że wartość krytycznego współczynnika uwalniania energii dla inicjacji pęknięcia jest wielkością niezależną od ukierunkowania włókien. Natomiast ułożenie włókien jest kluczowe w przypadku krytycznego współczynnika uwalniana energii dla propagacji pęknięcia.

4

Influence of a method of evaluation of the curvature of flexible vegetation elements on vertical distributions of flow velocities

Kubrak E., Kubrak J., Rowiński P.M.

Acta Geophysica

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2012

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Vol. 60, no. 4

1098-1119

EN

Methods of computing the deflections of flexible vegetation elements under the dynamic pressure of water were presented in the paper. Two methods, based on Euler–Bernoulli beam theory, were discussed, one designed for small deflections and the other, generalized one, also for larger deflections. The choice of the method for computations of deflections was discussed from the perspective of the computation of flow velocities above flexible vegetation. Computational results were compared with laboratory experiments and it was found that the simplified, computationally less expensive method may be used in many practical situations without deterioration of the results.

5

Resonance effects in Beroulli-Fuler beams under traveling load with variable speed

Bogacz R., Frischmuth K.

Logistyka

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2011

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nr 6

EN

Moving loads induce also in Euler-Bernoulli beams traveling waves. For a harmonic force moving at constant speed there exist analytical solutions with well known ranges of validity in the speed/frequency plane, divided by critical resonance curves. Recent applications to railway mechanics require the study of the variable speed case. Due to the lack of analytical solutions, numerical techniques have to be developed. As in the analytical approach, the crucial point is the discussion of the Sommerfeld condition in the case of infinite domains. In this paper, a semi-discretization of the equations is used together with an absorbing boundary condition. The method is verified on solutions to the classical case.

PL

Ruchome siły powodują propagację fal biegnących w belkach nawet w przypadku modelu Bernoulliego-Eulera. Gdy siła harmoniczna przemieszcza się ze stałą prędkością, istnieją rozwiązania analityczne. Znane są zakresy różnych postaci rozwiązań na płaszczyźnie prędkości i częstości, które rozdzielane są krzywymi rezonansowymi. Aktualne zastosowania w mechanice kolejowej wymagają analizy również przypadku zmiennej prędkości. Z braku rozwiązań analitycznych trzeba rozwijać techniki numeryczne. Ważnym punktem w przypadku belek nieograniczonych jest uwzględnienie warunków Sommerfelda. W artykule stosuje się metodę semi-dyskretyzacji z absorbującymi warunkami brzegowymi, która weryfikowana jest porównaniem z rozwiązaniami klasycznymi.

6

Histogram Thresholding using Beam Theory and Ambiguity Measures

Sen D., Pal S.K.

Fundamenta Informaticae

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2007

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Vol. 75, nr 1-4

483-504

EN

This paper presents a novel histogram thresholding technique based on the beam theory of solid mechanics and the minimization of ambiguity in information. First, a beam theory based histogram modification process is carried out. This beam theory based process considers a distance measure in order to modify the shape of the histogram. The ambiguity in the overall information given by the modified histogram is then minimized to obtain the threshold value. The ambiguity minimization is carried out using the theories of fuzzy and rough sets, where a new definition of rough entropy is presented. The applications of the proposed scheme in performing object and edge extraction in images are reported and compared with those of a few existing classical and ambiguity minimization based schemes for thresholding. Experimental results are given to demonstrate the effectiveness of the proposed method in terms of both qualitative and quantitative measures.

7

Linear and Non-Linear Dynamic Behaviour of an Axially Moving Viscoelastic Beam

Marynowski K.

Vibrations in Physical Systems

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2004

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Vol. 21

259--262

8

Modelling considerations for electrical motor stators

Couturier C., Lecointe J. P., Cassoret B.

Zeszyty Naukowe Katedry Mechaniki Stosowanej / Politechnika Śląska

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2002

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z. 19

17-23

9

A mathematical analysis of a smart-beam which is equipped with piezoelectric actuators

Destuynder P.

Control and Cybernetics

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1999

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Vol. 28, no 3

503-530

EN

First of all, a brief reminder on piezoelectric effect is given. Then it is applied to a beam equipped with such actuators. The influence of tile shape and location is discussed. A smart beam model is finally presented and analyzed. The controllability is carefully examined in the framework of the H.U.M. method of Lions (1988). Let us also underline that the asymptotic harmonic behaviour of the structure is videly used.