• Steel and Composite Structures
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• v.44 no.5
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• pp.619-632
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• 2022

There are numerous structural details (Longitudinal beam, web plate, U-ribs and I-ribs) in the top and bottom plates of steel box girders, which have significant influences on the longitudinal stress (normal stress) distribution. Clarifying the influence of these structural details on the normal stress distribution is important. In this paper, the ultra-wide steel box girder with large cantilevers of the Jinhai Bridge in China, which is the widest cable-stayed bridge in the world, has been analyzed. A 1:4.5 scale laboratory model of the steel box girder has been manufactured, and the influence of structural details on the normal stress distribution in the top and bottom plates for four different load cases has been analyzed in detail. Furthermore, a three-dimensional finite element model has been established to further investigate the influence regularity of structural details on the normal stress. The experimental and finite element analysis (FEA) results have shown that different structural details of the top and bottom plates have varying effects on the normal stress distribution. Notably, the U-ribs and I-ribs of the top and bottom plates introduce periodicity to the normal stress distribution. The period of the influence of U-ribs on the normal stress distribution is the sum of the single U-rib width and the U-rib spacing, and that of the influence of I-ribs on the normal stress distribution is equal to the spacing of the I-ribs. Furthermore, the same structural details but located at different positions, will have a different effect on the normal stress distribution.

• Smart Structures and Systems
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• v.15 no.5
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• pp.1345-1362
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• 2015

The present paper deals with the free vibration analysis of the functionally graded solid and annular circular plates with two functionally graded piezoelectric layers at top and bottom subjected to an electric field. Classical plate theory (CPT) is used for description of the all deformation components based on a symmetric distribution. All the mechanical and electrical properties except Poisson's ratio can vary continuously along the thickness direction of the plate. The properties of plate core can vary from metal at bottom to ceramic at top. The effect of non homogeneous index of functionally graded and functionally graded piezoelectric sections can be considered on the results of the system. $1^{st}$ and $2^{nd}$ modes of natural frequencies of the system have been evaluated for both solid and annular circular plates, individually.

• Ocean Systems Engineering
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• v.4 no.4
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• pp.263-278
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• 2014

The spudcan requires the suitable design considering the soil, platform, and environmental conditions. Its shape needs to be designed to secure sufficient reaction of soil so that it can prevent overturning accidents. Its shape also has to minimize the installation and extraction time. Even in the same soil condition, the reaction of soil may be different depending on the shape of spud can, mainly the slope of top and bottom plates. Therefore, in this study, the relation between the slope of plates and the reaction of soil with and without water jetting is analyzed to better understand their interactions and correlations. For the investigation, a wind turbine installation jack-up rig (WTIJ) is selected as the target platform and the Gulf of Mexico is considered as the target site. A multi layered (sand overlying two clays) soil profile is applied as the assumed soil condition and the soil-structure interaction (SSI) analysis is performed by using ANSYS to analyze the effect of the slope change of the bottom plate and water jetting on the reaction of soil. This kind of investigation and simulation is needed to develop optimal and smart spudcan with water-jetting control in the future.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.7
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• pp.877-884
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• 2001

A theoretical analysis is conducted on the Stokes flow in a narrow channel. A vertical fin is mounted on the bottom plate and the flow is induced by uniformly sliding top plate. The governing harmonic equation was solved in the transformed ζ-plane, which is obtained by applying conformal mappings to the physical plane. By using well-known transformation technique, closed-form expressions for velocity and skin frictional stress on the top and bottom plates were obtained.

• Structural Engineering and Mechanics
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• v.40 no.5
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• pp.665-688
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• 2011

This paper presents a theoretical analysis for the free vibration of rectangular tanks partially filled with an ideal liquid. Wet dynamic displacements of the tanks are approximated by combining the orthogonal polynomials satisfying the boundary conditions, since the rectangular tanks are composed of four rectangular plates. The classical boundary conditions of the tanks at the top and bottom ends are considered, such as clamped, simply supported, and clamped-free boundary conditions. As the facing rectangular plates are assumed to be geometrically and structurally identical, the vibration modes of the facing plates of the tanks can be divided into two categories: symmetric and antisymmetric modes with respect to the planes passing through the center of the tanks and perpendicular to the free liquid surface. The liquid displacement potentials satisfying the Laplace equation and liquid boundary conditions are derived, and the wet dynamic modal functions of a quarter of the tanks can be expanded by the finite Fourier transform for compatibility requirements along the contacting surfaces between the tanks and liquid. An eigenvalue problem is derived using the Rayleigh-Ritz method. Consequently, the wet natural frequencies of the rectangular tanks can be extracted. The proposed analytical method is verified by observing an excellent agreement with three-dimensional finite element analysis results. The effects of the liquid level and boundary condition at the top and bottom edges are investigated.

• Journal of the Korean Solar Energy Society
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• v.29 no.3
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• pp.59-65
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• 2009

In this paper, to find effective way of the production of the distilled water with solar radiation, 4 different boxes of condensation systems were compared. The bottom size of boxes are identical but the angles of top collecting plates are different. During the solar radiation, condensation did not occur and the condensation start when solar radiation was decreased. The maximum condensation reached when the temperatures of the top and bottom parts are equal. The condensation was continued until sunrise with gradually reduced amount. When top plate angle was $45^{\circ}$, condensation was highest compared with the other angles.

• Structural Engineering and Mechanics
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• v.23 no.2
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• pp.115-127
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• 2006

The axisymmetric free vibrations of transversely isotropic magnetoelectroelastic laminated circular plates are studied. Based on the three-dimensional governing equations of magnetoelectroelastic medium, the state space equations of laminated circular plates are obtained. By using the finite Hankel transform and rendering the free terms left by the transform in terms of the boundary quantities, the solutions of the state space equations are given for two kinds of boundary conditions. The frequency equations of the free vibration are derived using the propagator matrix method and the boundary conditions at top and bottom surfaces. By virtue of the inverse Hankel transform, the mode shapes are also determined. Since the solutions strictly satisfy the governing equations in the region and the boundary conditions at the edges, they are the three-dimensionally exact. Finally, the natural frequencies of such plates are tabulated and compared with those of the piezoelectric and elastic plates in the numerical example.

• Wind and Structures
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• v.23 no.6
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• pp.543-558
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• 2016

The response of functionally graded ceramic-metal plates is investigated using theoretical formulation, Navier's solutions, and a new displacement based on the high-order shear deformation theory are presented for static analysis of functionally graded plates. The theory accounts for a quadratic variation of the transverse shear strains across the thickness, and satisfies the zero traction boundary conditions on the top and bottom surfaces of the plate without using shear correction factors. The plates are assumed to have isotropic, two-constituent material distribution through the thickness, and the modulus of elasticity of the plate is assumed to vary according to a power-law distribution in terms of the volume fractions of the constituents. Numerical results of the new refined plate theory are presented to show the effect of the material distribution on the deflections, stresses and fundamental frequencies. It can be concluded that the proposed theory is accurate and simple in solving the static and free vibration behavior of functionally graded plates.

• Structural Engineering and Mechanics
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• v.62 no.3
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• pp.311-324
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• 2017

In this paper a new eight-unknown higher order shear deformation theory is proposed for functionally graded (FG) material plates. The theory based on full twelve-unknown higher order shear deformation theory, simultaneously satisfy zeros transverse stresses at top and bottom surface of FG plates. Equations of motion are derived from principle of virtual displacement. Exact closed-form solutions are obtained for simply supported rectangular FG plates under uniform loading. The accuracy of present numerical results has been verified by comparing it with generalized shear deformation theory. The effect of power law index of functionally graded material, side-to-thickness ratio, and aspect ratio on static behavior of FG plates is investigated.

• International Journal of Air-Conditioning and Refrigeration
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• v.17 no.4
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• pp.123-128
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• 2009

In this paper, effective ways to produce distilled water with solar radiation was investigated. Four different boxes of condensation systems were compared. The bottoms of the boxes were identical, but the angles of the top collecting plates were different. During the solar radiation, condensation did not occur. Condensation started when solar radiation was decreased. The maximum condensation was found when the temperatures of the top and bottom parts were equal. The condensation was continued until sunrise with gradually reduced rate. When the collecting plate angle was $45^{\circ}$, condensation was the highest compared with other angles.