• Economic and Environmental Geology
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• v.41 no.5
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• pp.509-516
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• 2008

For analyzing resources demand appropriately, corresponding demand data is essential. But it is hard to get the suitable data of each resource demand, because every resources has various type as refined and many kind of alloyed. That reason makes many analyses to employ the data of refined metals as the representative quantity. But those refined metals are factors for producing final goods so those in domestic market are not always meant for producing domestic end goods. Thus in this paper, the domestic demands of refined copper, lead and zinc are analyzed empirically with 'intensity of use' and foreign countries' income variable applied model for recovering the data availability.

• Journal of Korean Society of Steel Construction
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• v.13 no.5
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• pp.535-545
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• 2001

A refined method of analysis which is called the Advanced Analysis has been introduced This method is to consider the intial member imperfection residual stress and second-order effects so as to estimate the overall behavior of steel frame accurately Based on the refined plastic hinge method that is more suitable and practical in design practice. the program RPH-2DF is coded using the log model which represents the moment-rotation relationship of connection. The validity of this program is examined by frame test data. Finally to investigate the difference between behaviors of rigid and semi-rigid frame. the 10-story frame analysis results designed by MIDAS-GEN v4.2.2 are compared with the results by RPH-2DF.

• Structural Engineering and Mechanics
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• v.14 no.5
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• pp.575-593
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• 2002

Based on the Mindlin plate theory, a refined discrete 15-DOF triangular laminated composite plate finite element RDTMLC with the re-constitution of the shear strain is proposed. For constituting the element displacement function, the exact displacement function of the Timoshenko's laminated composite beam as the displacement on the element boundary is used to derive the element displacements. The proposed element can be used for the analysis of both moderately thick and thin laminated composite plate, and the convergence for the very thin situation can be ensured theoretically. Numerical examples presented show that the present model indeed possesses the properties of higher accuracy for anisotropic laminated composite plates and is free of locking even for extremely thin laminated plates.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2000.04a
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• pp.89-92
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• 2000

In this paper, an effective procedure is presented for the local recovery of displacements and stresses in multilayered composite panels, which incorporate the local refinement using mesh superposition. The mesh superposition method is used to refine the global coarse mesh by superimposing refined mesh to the localized zone of interest without transition zones. The finite element model used is a solid element based on the Hellinger-Reissner variational principle. The a posteriori computation of the through-the-thickness distributions of displacements and stresses is achieved using a predictor-corrector procedure. The procedure utilizes the superconvergent stresses and nodal displacements of the finite element patch. The element patch is generated by locally superimposing a refined local mesh to the coarse global mesh.

• Steel and Composite Structures
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• v.37 no.1
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• pp.37-49
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• 2020

In this paper, free vibration finite element analysis of axially moving laminated composite beams subjected to axial tension is studied. It is assumed that the beam has a constant axial velocity and is subject to uniform axial tension. The analysis is based on higher-order theories that have been presented by Carrera Unified Formulation (CUF). In the CUF technique, the three dimensional (3D) displacement fields are expressed as the approximation of the arbitrary order of the displacement unknowns over the cross-section. This higher-order expansion is considered in equivalent single layer (ESL) model. The governing equations of motion are obtained via Hamilton's principle. Finally, several numerical examples are presented and the effect of the ply-angle, travelling speed and axial tension on the natural frequencies and beam stability are demonstrated.

• Computers and Concrete
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• v.27 no.3
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• pp.269-282
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• 2021

A dynamic analytical solution for a simply supported, rectangular functionally graded plate with a porous middle layer under time-dependent load based on a refined third-order shear deformation theory with a cubic variation of in-plane displacements according to the thickness and linear/quadratic transverse displacement is presented. The solution achieved in the trigonometric series form and rests on the Green's function method. Two porosity types and their influence on material properties, and mechanical behavior are considered. The network of pores is assumed to be empty or filled with low-pressure air, and the material properties are calculated using the power-law distribution idealization. Numerical calculations have been carried out to demonstrate the accuracy of the kinematic model for the dynamic problem, the effect of porosity, thickness of porous layers, power-law index, and type of loading on the dynamic response of an imperfect functionally graded material plate.

• Coupled systems mechanics
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• v.9 no.6
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• pp.575-597
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• 2020

Equilibrium equations of a porous FG plate resting on Winkler-Pasternak foundations with various boundary conditions are derived using a new refined shear deformation theory. Different types of porosity distribution rate are considered. Governing equations are obtained including the plate-foundation interaction. This new model meets the nullity of the transverse shear stress at the upper and lower surfaces of the plate. The novel rule of mixture is proposed to describe and approximate material properties of the FG plates with different distribution case of porosity. The validity of this theory is studied by comparing some of the present results with other higher-order theories reported in the literature. Effects of variation of porosity distribution rate, boundary conditions, foundation parameter, power law index, plate aspect ratio, side-to-thickness ratio on the deflections and stresses are all discussed.

• Coupled systems mechanics
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• v.13 no.4
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• pp.337-357
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• 2024

This paper studies, the analysis of nonlinear thermal vibration of fluid-infiltrated FG nanobeam with voids. The effect of nonlinear thermal in a FG ceramic-metal nanobeam is determined using Murnaghan's model. Here the influence of fluids in the pores is investigated using the Skempton coefficient. Hamilton's principle is used to find the equation of motion of functionally graded nanobeam with the effect of refined higher-order state space strain gradient theory (SSSGT). Numerical solutions of the FG nanobeam are employed using Navier's solution. These solutions are validated against the impact of various parameters, including imperfection ratio, fluid viscosity, fluid velocity, amplitude, and piezoelectric strain, on the behavior of the fluid-infiltrated porous FG nanobeam.

• Proceedings of the Korea Concrete Institute Conference
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• 1992.10a
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• pp.111-118
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• 1992

The mechanical behaviors related to the strain rate effect and the tensile strength of high-strength concrete were investigated in this study. For this purpose, concrete cylinder specimens with 4 different compressive strengths from 232kg/$\textrm{cm}^2$ to 1113kgf/$\textrm{cm}^2$ were tested and analysed on the mechanical properties(stress-strain relationship, compressive, modulus of elasticity, strain at peak compressive stress). From this experimental and analytical study, it seems that the current prediction model(ACI) for modulus of rupture need to be refined. Therefore, more refined equations for evaluation tensile strength of concrete are proposed.

• Steel and Composite Structures
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• v.1 no.1
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• pp.111-130
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• 2001

This paper presents an effective, reliable and accurate method for prediction of structural behaviour of steel frames at elevated temperature. The refined plastic hinge method, which has been used successfully in the second-order elasto-plastic analysis of steel frames at ambient conditions, is adopted here to allow for time-independent fire effects. In contrast to the existing rigorous finite element programs, the present method uses the advanced analysis technique that provides a simple and reliable means for practical study of the behaviour of steel frames at elevated temperature by a limiting stress model. The present method is validated against other test and numerical results.