• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1995년도 추계학술대회논문집
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• pp.69-75
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• 1995

The deformation behavior of stainless steel-clad aluminum sheet metals under uniaxial tension has been investigated. The differences in mechanical properties such as elastic modulus, flow stress and plastic strain ratio, of component layers of the composite sheet gave rise to warping of the tensile specimens. The warping has been analyzed by FEM and the total force and momentum equilibria. The analyzed radii of curvature of the warped specimens were smaller than the measured data possibly due to elastic recovery during unloading. The differences in mechanical properties may also give rise to transverse stresses in the component layers. The transverse stresses have been analyzed on the assumption of isostrain and by the FEM in which the warping has been taken into account. The transverse stresses calculated by the FEM were lower than those by the isostrain hypothesis due to stress relaxation by the warping and turned out to be negligible compared with the longitudinal stresses. Consequently, the flow stresses of the composite sheets follow the rule of mixtures.

• 대한기계학회논문집A
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• 제24권9호
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• pp.2292-2301
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• 2000

We propose an accurate and efficient estimation method of transverse shear stresses for analysis and design of laminated composite structures by 4-node quadrilateral degenerated shell elements. To get proper distributions of transverse shear stresses in each layer, we use 3-dimensional equilibrium equations instead of constitutive equations with shear correction factors which vary diversely according to the shapes of shell sections. Three dimensional equilibrium equations are integrated through the thickness direction with complete polynomial membrane stress fields, which are recovered by REP (Recovery by Equilibrium in Patches) recovery method. The 4-node quadrilateral degenerated shell element used in this paper has drilling degrees of freedom and shear stresses derived from assumed strain fields that are set up at natural coordinate systems. The numerical results demonstrate that the proposed estimation method attains reasonable accuracy and efficiency compared with other methods and FE analysis using 4-node degenerated shell elements.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1999년도 춘계 학술발표회 논문집 Proceedings of EESK Conference-Spring
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• pp.239-246
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• 1999

recently there have been many destructive seismic events in Kobe Japan in 1995 and in Northridge California USA in 1994. etc. The Korean Bridge Design Standard Specifications adopted the seismic design requirements in 1992. Comparing the earthquake magnitude in Korea with those in the west coast of the USA it may be said that the current seismic design requirements of the Korean Bridge Design Standard Specifications provides too conservation design results especially for transverse reinforcement details and amount in reinforced concrete columns. This fact usually makes construction problems in concrete casting due to transverse reinforcement congestion. And the effective stiffness Ieff depends on the axial load P(Ag{{{{ {f }_{ck } }}) and the longitudinal reinforcement ratio Ast/Ag and it is conservative to use the effective stiffness Ieff than the gross section moment Ig. Seismic design for transverse reinforcement content of concrete column is considered of extreme-fiber compression strain R-factor axial load and stiffness etc.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.345-348
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• 2004

In this paper it is to establish a comprehensive model for predicting damping in sandwich Laminated composites on the basis of strain energy method. In this model, the effect of transverse shear on the material damping has been considered with in-plane stresses. Results showed that the viscoelastic core thickness in the sandwich beam and the Length of a beam have a high impact on the material damping. The transverse shear appears to be highly influenced by the damping behavior in $0^0$ laminated sandwiched composites. However, it is Little influenced by that in $90^0$ laminated sandwiched composites.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2000년도 춘계 학술발표회 논문집 Proceedings of EESK Conference-Spring
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• pp.202-212
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• 2000

This study investigates the ductility capacity of slender-wide reinforced concrete walls under predominant flexural moment loading. The experimental work for this study aims to provide design guidelines for bar detailing in critical regions under compressive stress in particular in case of slender-wide RC walls. According to the experimental observation the Bernoulli hypothesis of linear strain distribution is no longer valid and the ultimate compressive strain of concrete is significantly reduced, It is postulated that the nonlinear strain distribution causes the concentrated compressive stressed region and hence the premature crushing failure at the toe of walls. The reduced ultimate strain and nonlinear strain distribution need transverse reinforcement for confinement and more realistic models for the strength and displacement estimation of slender-wide RC wall.

• Computers and Concrete
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• 제12권4호
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• pp.537-552
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• 2013

Computation of flexural ductility of reinforced concrete beam sections has been proposed by taking into account strain rate sensitive constitutive behavior of concrete and steel, confinement of core concrete and degradation of cover concrete during load reversal under earthquake loading. The estimate of flexural ductility of reinforced concrete rectangular sections has been made for a wide range of tension and compression steel ratios for confined and unconfined concrete at a strain rate varying from $3.3{\times}10^{-5}$ to 1.0/sec encountered during normal and earthquake loading. The parametric studies indicated that flexural ductility factor decreases at increasing strain rates. Percentage decrease is more for a richer mix concrete with the similar reinforcement. The confinement effect has marked influence on flexural ductility and increase in ductility is more than twice for confined concrete (0.6 percent volumetric ratio of transverse steel) compared to unconfined concrete. The provisions in various codes for achieving ductility in moment resisting frames have been discussed.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.89-92
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• 2006

In order to achieve target ductility the stress-strain relation of confined concrete is indispensible. In this study the specimens with different transverse reinforcement ratios were tested. The test results were compared with empirical equations and the characteristics of confinement effect were investigated.

• Journal of Magnetics
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• 제5권1호
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• pp.1-3
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• 2000

We have theoretically investigated changes in reflection coefficients induced by misfit strain located near the interface between an iron-yttrium garnet magnetic film and a nonmagnetic gadolinium-gallium garnet substrate in a transverse magneto-optical configuration.

• Computers and Concrete
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• 제8권1호
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• pp.23-41
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• 2011

The behaviour of concrete confined by transverse reinforcement is a classical topic. Numerous studies have been conducted to establish the stress-strain relationships for concrete under various confining reinforcement arrangements. Many empirical and semi-empirical formulas exist. Simplified analytical models have also been proposed to evaluate the increase in the strength and ductility of confined concrete. However, relatively few studies have been conducted to utilise advanced computational models for a realistic simulation of the behaviour of concrete confined by transverse reinforcement. As a matter of fact, high fidelity simulations using the latest numerical solvers in conjunction with advanced material constitutive models can be a powerful means to investigating the mechanisms underlying the confining effects of different reinforcement schemes. This paper presents a study on the use of high fidelity finite element models for the investigation of the behaviour of concrete confined by stirrups, as well as the interpretation of the numerical results. The development of the models is described in detail, and the essential modelling considerations are discussed. The models are then validated by simulating representative experimental studies on short columns with different confining reinforcement schemes. The development and distribution of the confining stress and the subsequent increase in the axial strength are examined. The models are shown to be capable of reproducing the behaviour of the confined concrete realistically, paving a way for systematic parametric studies and investigation into complicated confinement, load combination, and dynamic loading situations.

• Journal of Advanced Marine Engineering and Technology
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• 제7권1호
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• pp.49-63
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• 1983

Coupled transverse shaft vibrations have become the target of great concern in high powered ships such as container ships. Due to increasing ship's dimensions and high propulsive power, resonance frequencies of the propeller shaft system tend to decrease and can appear in some cases within the operating speed range of engine. In this connection, the coupled free transverse vibrations of shaft system in two planes are theoretically investigated. This shaft system carries a number of discs and is flexibly supported by a number of bearing stiffness are considered for the calculation. Transfer matrix method is applied to calculate the shaft responses in both planes. A digital computer program is developed to calculate the shaft responses of the coupled transverse vibrations in two planes. An experimental model shaft system is made. It is composed of a disc, shafts, ball bearings thrust bearings and flexible bearing supports. The shaft system is excited by an electrical magnet, and shaft vibration responses in two planes are measured with the strain gage system. From these measurements, the natural frequencies of the shaft system in both planes are found out. The developed program is also used to calculate the shaft vibration responses of experimental model shaft system. From the results of these calculations, the natural frequencies of shaft system in two planes are derived. Theoretical predictions of model shaft natural frequencies show good agreements with its esperimental measurements.