• Structural Engineering and Mechanics
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• v.64 no.3
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• pp.311-321
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• 2017

This paper presents the details of analytical studies carried out towards the prediction of flexural capacity and load-deflection behaviour of Laced Steel-Concrete Composite (LSCC) beams. Analytical expressions for flexural capacity of the beams are derived in accordance with the basic principles of conventional Reinforced Concrete (RC) beams, but incorporated with relevant modifications to account for the composite nature of the cross-section. The ultimate flexural capacity of the two LSCC beams predicted using the derived expressions is found to be approximately 20% lower than those obtained due to measurement from experiments. Further to these, two simple methods are also proposed on the basis of unit load method and equivalent steel beam method to determine the non-linear load-deflection response of the LSCC beams for monotonic loading. Upon validation of the proposed methods by comparing the predicted responses with those of experiments and finite element analysis, it is found that the methods are useful to find nonlinear response of such composite beams.

• Land and Housing Review
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• v.2 no.2
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• pp.189-194
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• 2011

To reinforce bearing capacity-changed section or different foundation in the same building, empirical or simple tools have been used. To solve this problem, we suggest the analytical solution that can evaluate and reinforce the stability of foundation. To estimate the effect of reinforcement by replacement in different foundation, soil stiffness evaluation method taking into account the influence factor with respect to depth beneath the foundation need to be applied. In this paper, graphs and relevant formulae are suggested to calculate equivalent soil reaction coefficient showing the effect of reinforcement by crushed stone and lean concrete replacement.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2004.11a
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• pp.183-187
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• 2004

To predict rolling performance for a barge-type FPSO, the evaluation of correct nonlinear roll damping is critical. The squall section of FPSO causes a fair amount of viscous damping effect. Free roll decoy tests were conducted to estimate nonlinear roll damping for a barge-typ FPSO of three different loading conditions. The roll motion RAO was deduced by model tests in the wave condition of wideband spectrum. In numerical calculation, the quadratic damping was considered as equivalent linear damping using the results of free roll decay test. Tested roll performance in JONSWAP wave spectrum was compared with numerical results. These two results show good agreement, in spite of proximity in peak wave period and roll natural period.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.6
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• pp.1500-1505
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• 2008

To evaluate the structural integrity of the nuclear seismic category IIA bellows seal 2" globe valve under the seismic service conditions the seismic analysis was performed in accordance with ASME, section III, ND-3500, 1989 edition. The finite element computer program, ANSYS, Version 10.0, is used to perform both a mode frequency analysis and an equivalent static seismic analysis of the valve assembly. The mode frequency analysis results show the fundamental natural frequency is greater than 33 Hz and does not exist in seismic range, thus justifying the use of the static analysis. The stresses resulted from various loadings and their combinations are within the allowable limits specified in the above mentioned ASME code. The results of the seismic evaluation fully satisfied the structural acceptance criteria of the ASME code. Accordingly the structural integrity on the globe valve was proved.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.12
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• pp.1782-1791
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• 2017

In this paper, an optimal design of hybrid magnetic levitation(Maglev) system using intelligent optimization algorithms is proposed. The proposed maglev system adopts hybrid suspension system with permanent-magnet(PM) and electro magnet(EM) to reduce the suspension power loss and the teaching-learning based optimization(TLBO) that can overcome the drawbacks of conventional intelligent optimization algorithm is used. To obtain the mathematical model of hybrid suspension system, the magnetic equivalent circuit including leakage fluxes are used. Also, design restrictions such as cross section areas of PM and EM, the maximum length of PM, magnetic force are considered to choose the optimal parameters by intelligent optimization algorithm. To meet desired suspension power and lower power loss, the multi object function is proposed. To verify the proposed object function and intelligent optimization algorithms, we analyze the performance using the mean value and standard error of 10 simulation results. The simulation results show that the proposed method is more effective than conventional optimization methods.

• Composites Research
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• v.33 no.6
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• pp.377-382
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• 2020

The free vibration characteristics of corrugated laminated composite plates with axial stiffeners is investigated using the Rayleigh-Ritz method. The plate is stiffened by beams with open cross-section area. The equivalent homogenization model is used for the corrugated laminated composite plates. This homogenization model is treated a corrugated plate as an orthotropic plate that has different material properties in two perpendicular directions. The motion of equivalent plate is represented on the basis of the first order shear deformation theory (FSDT) to account for the effect of rotary inertia and transverse shear deformation. Stiffeners are considered as discrete elements to predict the local vibration mode to be generated by the presence of stiffeners. To validate the proposed analytical approach, natural frequencies and vibration mode shapes from the analytical method are compared with those from the FEA by ANSYS.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.3
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• pp.201-207
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• 2004

This paper is a study on the recognition of continuous speech and uses a method of speech recognition using syntactic analysis and one-stage DMS/DP. In order to perform the speech recognition, first of all, we make DMS model by section division algorithm and let continuous speech data be recognized through One-stage DMS/DP method using syntactic analysis. Besides the speech recognition experiments of proposed method, we experiment the conventional one-stage DP method under the equivalent environment of data and conditions. From the recognition experiments, it is shown that Ole-stage DMS/DP using syntactic analysis is superior to conventional method.

• Computers and Concrete
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• v.2 no.3
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• pp.177-188
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• 2005

This paper presents a numerical model developed to evaluate the load-deflection and moment-curvature relationship for concrete beams strengthened externally with four different Fiber Reinforced Polymer (FRP) composite systems. The developed model considers the inelastic behavior of concrete section subjected to a combined axial force and bending moment. The model accounts for tensile strength of concrete as defined by the modulus of rupture of concrete. Based on the adopted material constitutive relations, the model evaluates the sectional curvature as a function of the applied axial load and bending moment. Deflections along the beam are evaluated using a finite difference technique taking into account support conditions. The developed numerical technique has been tested on a cantilever beam with a transverse load applied at its end. A study of the behavior of the beam with tension reinforcement compared to that with FRP areas giving an equivalent ultimate moment has been carried out. Moreover, cracking of the section in the tensile region at ultimate load has also been considered. The results indicated that beams reinforced with FRP systems possess more ductility than those reinforced with steel. This ductility, however, can be tuned by increasing the area of FRP or by combining different FRP layers.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.8
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• pp.997-1009
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• 1999

Silica particle formation and growth process including chemical reaction, coagulation and sintering was studied in a counterflow diffusion flame burner. The counterflow geometry provides a one dimensional flow field, along the stagnation point streamline, which greatly simplifies interpretation of the particle growth characteristics. $SiCl_4$ has been used as the source of silicon in hydrogen/oxygen/argon flames. The temperature profiles obtained by calculation showed a good agreement with experiment data. Using one and two dimensional sectional method, aerosol dynamics equation in a flame was solved, and these two results were compared. The two dimensional section method can consider sintering effect and growth of primary particle during synthesis, thus it showed evolution of morphology of non-spherical particles (aggregates) using surface fractal dimension. The effects of flame temperature and chemical loading on particle dynamics were studied. Geometric mean diameter based on surface area and total number concentration followed the trend of experiment results, especially, the change of diameters showed the sintering effect in high temperature environment.

• Structural Engineering and Mechanics
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• v.62 no.3
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• pp.273-279
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• 2017

A meso-scale model is proposed to study filament-wound composites with fiber undulations and crossovers. First, the crossover and undulation region is classified as the circumferential undulation and the helical undulation. Next, the two undulations are separately regarded as a series of sub-models to describe the meso-structure of undulations by using meso-parameters such as fiber orientation, fiber inclination angle, resin rich area, fiber volume fraction and bundle cross section. With the meso-structure model and the classic laminate theory, a method for calculating the stiffness of filament wound composites is eventually established. The effects of the fiber inclination angle, the fiber and resin volume fraction and the resin rich area on the stiffness are studied. The numerical results show that the elastic moduli for the circumferential undulation region decrease to a great extent as compared with that of the helical undulation region. Moreover, significant decrease in the elastic and shear moduli and increase in the Poisson's ratio are also found for the resin rich area. In addition, thickness and bundle section have evident effect on the equivalent stiffness of the fiber crossover and the undulation region.