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1

A study on RCFST column instability modes

Lu Zhengran, Guo Chao

Archives of Civil Engineering

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2022

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Vol. 68, nr 2

211--225

EN

In this work, the instability damage modes of yield state of a steel tube at the tension side of a rectangular steel tube-confined concrete (RCFST) column under eccentric compression were classified into two types based on the coupling effect of slenderness ratio (λ) and eccentricity ratio (γ). The two types include the unilateral compression yield failure mode with a smaller value of γ and tensile and compressive yield failure modes on both column sides with a larger value of γ. Further, the parametric analyses were performed by employing the finite element (FE) method and the analytical analysis to test 16 groups of RCFST columns by varying the γ value with different λ values. It was observed that the results of the analysis for the mechanical properties like the responses of load-strain (Ρ-ε) and RCFST column instability modes correlated well with the results obtained in the experiments. Furthermore, the proposed theoretical method could be used to investigate the roles of γ as a controller against the instability in RCFST columns when compared with λ.

2

Large amplitude free vibration analysis of tapered Timoshenko beams using coupled displacement field method

Rajesh K., Saheb K. M.

International Journal of Applied Mechanics and Engineering

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2018

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Vol. 23, no. 3

673--688

EN

Tapered beams are more efficient compared to uniform beams as they provide a better distribution of mass and strength and also meet special functional requirements in many engineering applications. In this paper, the linear and non-linear fundamental frequency parameter values of the tapered Timoshenko beams are evaluated by using the coupled displacement field (CDF) method and closed form expressions are derived in terms of frequency ratio as a function of slenderness ratio, taper ratio and maximum amplitude ratio for hinged-hinged and clamped-clamped beam boundary conditions. The effectiveness of the CDF method is brought out through the solution of the large amplitude free vibrations, in terms of fundamental frequency of tapered Timoshenko beams with axially immovable ends. The results obtained by the present CDF method are validated with the existing literature wherever possible.

3

Buckling stability assessment of plates under uniaxial compression

Riahi Farhad, Zirakian Tadeh, Ghaderi Vahed Mam, Arya Souran

Advances in Science and Technology. Research Journal

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2018

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Vol. 12, no 2

97--105

EN

Buckling of thin-walled and load-bearing elements of a structure can have devastating consequences. Hence, buckling checks are an integral part of strength analysis of structures. The buckling problem of thin rectangular plates subjected to in-plane compressive and/or shear loading is of great importance in building, bridge, aerospace, marine, and shipbuilding industries. When buckling occurs, thin plates undergo large out-of-plane deflections, which in turn results in the development of large bending stresses and eventually complete failure of the structure. This paper deals with the buckling stability assessment of uniaxially-compressed plates with different support conditions within the framework of classical plate theory. The main objective of this research is to explore some uncovered aspects of buckling stability of plates by considering the effects of support conditions, aspect ratio, and slenderness ratio, which will consequently result in efficient design of such thin-walled structures. To this end, in addition to validation of the numerical simulation, some case studies have been performed in order to gain a better understanding of different aspects of buckling stability of such thin-walled structures.

4

Large amplitude free vibration analysis of tapered timoshenko hinged-hinged beam using coupled displacement field method

Korabathina R., Koppanati M. S.

Vibrations in Physical Systems

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2017

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Vol. 28

art. no. 2017007

EN

Tapered beams are more efficient compared to uniform beams as they provide a better distribution of mass and strength and also meet special functional requirements in many engineering applications like architecture, aeronautical, civil, mechanical, automobile, nuclear and robotics. The authors proposed a new method called Coupled Displacement Field (CDF) method in which the displacement field such as total rotation is assumed such that the assumed displacement must satisfy the kinematic and force boundary condition of the beam. The lateral transverse displacement is derived from the coupling equation which is derived from the static equilibrium conditions of the beam. By the application of principle of minimum total potential energy for different beam boundary conditions, the fundamental frequency parameter value is calculated in terms of taper ratio and slenderness ratio for various maximum amplitude ratios of the tapered Timoshenko shear flexible hinged-hinged beam boundary condition.