• Journal of the Earthquake Engineering Society of Korea
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• v.16 no.6
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• pp.13-20
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• 2012

In this study, 5-story structures were designed in accordance with KBC2009 for inelastic time history analysis of RC IMRF. Bending moment-curvature relationship for beam and column was identified with fiber model and bending moment-rotation relationship for beam-column joint was calculated with simple and unified joint shear behavior model and moment equilibrium relationship for the joint. The hysteretic behavior was simulated with three-parameter model suggested in IDARC program. The analytical results showed that the inelastic shear behavior of the joint could be neglected in the structural design for seismic design category C but the structure of category D did not satisfy the criteria of FEMA 356 for collapse prevention performance level.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.7 s.172
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• pp.38-46
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• 2005

In laser machining such as drilling with $CO_2$ or Nd:YAG laser, and etching or ablation with Excimer laser, one of the most important parameters affecting the machining is known to be beam characteristics. In this paper a numerical study is performed to investigate the effects of beam parameters, especially in the process of excimer laser ablation of polymers. Results of different beam conditions reveal that if the ablated depth is small compared to beam size the simple photochemical etching model is suitable to predict the etched shape, and that the importance of precise alignment becomes large as beam quality factor becomes larger.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.113-115
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• 2002

The Monte Carlo simulation method is a numerical solution to a problem that models objects interacting with other objects or their environment based upon simple object-object or object-environment relationships. In spite of its great accuracy, It was turned away because of long calculation time to simulate a model. But, it is used to simulate a linear accelerator frequently with the advance of computer technology. To simulate linear accelerator in Monte Carlo simulations, there are many parameters needed to input to Monte Carlo code. These data can be supported by a linear accelerator manufacturer. Although the model of a linear accelerator is the same, a different characteristic property can be found. Thus, we performed a commissioning process of 6MV photon beam in Varian 2300C/D model with BEAM/EGS4 Monte Carlo code. The head geometry data were put into BEAM/EGS4 data. The mean energy and energy spread of the electron beam incident on the target were varied to match Monte Carlo simulations to measurements. TLDs (thermoluminescent dosimeter) and radiochromic films were employed to measure the absorbed dose in a water phantom. Beam profile was obtained in 40cm${\times}$40cm field size and Depth dose was in 10cm${\times}$10cm. At first, we compared the depth dose between measurements and Monte Carlo simulations varying the mean energy of an incident electron beam. Then, we compared the beam profile with adjusting the beam radius of the incident electron beam in Monte Carlo simulation. The results were found that the optimal mean energy was 6MV and beam radius of 0.1mm was well matched to measurements.

• 유체기계공업학회:학술대회논문집
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• 2004.12a
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• pp.98-103
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• 2004

This paper presents modeling and simulation of the bump foil bearings with consideration of the elastic behavior of the foil and gas compressibility. Heshmat had originally introduced the simple compliance model to estimate the EHL(elasto-hydrodynamic lubrication) performance. But this approach can not consider the deflection of top foil at the edge of bearing, so model is insufficient to analyze in case that the eccentricity ratio is greater than I. So the top foil is considered as a simple beam model supported by linear spring elements, and the bump foil deflection can be simple compliance model. The EHL calculations are performed for convention rigid type, classical foil type, variable pitch type and double bump type toil bearings. This paper presents that 2nd or 3rd generation bearings have excellent performance in every speeds.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.14 no.4
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• pp.11-16
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• 2006

The wind turbine rotor blade is faced with various aeroelastic problem as rotor blades become bigger and lighter by the use the composite material. The aeroelastic analysis of a wind turbine rotor blade requires its aerodynamic model and structural model. For effective aeroelastic analysis, it is required the simple and effective structural model of the blade. In the present study, we introduce the effective equivalent structural modeling of the blade for aeroelastic analysis. The equivalent beam model of the composite blade based on its 3D finite element model is established. The free vibration analysis shows that the equivalent beam model of the blade is equivalent to its 3D finite element model.

• Structural Engineering and Mechanics
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• v.23 no.6
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• pp.635-649
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• 2006

The static and dynamic responses of guyed telecommunication towers can be determined by using two models, the space truss element model, and the equivalent beam-column element model. The equivalent beam-column analysis is based on the determination of the equivalent shear, torsion, and bending rigidities as well as the equivalent area of the guyed mast. In the literature, two methods are currently available to determine the equivalent properties of lattice structures, namely: the unit load method, and the energy approach. In this study, an equivalent beam-column analysis is introduced based on an equivalent thin plate approach for lattice structures. A finite-element modeling, using suitably modified ABAQUS software, is used to investigate the accuracy of utilizing the different proposed methods in determining the static and dynamic responses of a guyed tower of 364.5-meter high subjected to static and seismic loading conditions. The results from these analyses are compared to those obtained from a finite-element modeling of the actual structure using 3-D truss and beam elements. Good agreement is shown between the different proposed beam-column models, and the model of the actual structure. However, the proposed equivalent thin plate approach is simpler to apply than the other two approaches.

• Structural Engineering and Mechanics
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• v.64 no.2
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• pp.145-153
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• 2017

In this article, a novel simple higher-order shear deformation theory for bending and free vibration analysis of functionally graded (FG) beams is proposed. The beauty of this theory relies on its 2-unknowns displacement field as the Euler-Bernoulli beam theory, which is even less than the Timoshenko beam theory. A shear correction factor is, therefore, not needed. Equations of motion are obtained via Hamilton's principle. Analytical solutions for the bending and free vibration analysis are given for simply supported beams. Efficacy of the proposed model is shown through illustrative examples for bending and dynamic of FG beams. The numerical results obtained are compared with those of other higher-order shear deformation beam theory results. The results obtained are found to be accurate.

• Advances in materials Research
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• v.13 no.5
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• pp.335-353
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• 2024

In the present paper, a simple quasi-3D integral higher-order beam theory (HBT) is presented, in which both shear deformation and thickness stretching effects are included for mechanical analysis of advanced composite beams with simply supported boundary conditions, handling mainly bending, buckling, and free vibration problems. The kinematics is based on a novel displacement field which includes the undetermined integral terms and the parabolic function is used in terms of thickness coordinate to represent the effect of transverse shear deformation. The governing equilibrium equations are drawn from the dynamic version of the principle of virtual work; whereas the solution of the problem is obtained by assuming a Navier technique for simply supported advanced composite beams subjected to sinusoidally and uniformly distributed loads. The correctness of the present computational method is checked by comparing the obtained numerical results with quasi-3D solutions found in the literature and with those provided by other shear deformation beam theories. It can be confirmed that the proposed model, which does not involve any shear correction factor, is not only accurate but also simple and useful in solving the static and dynamic response of advanced composite beams.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1989.04a
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• pp.50-55
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• 1989

Piping systems are composed of pipes with various thickness, diameter and length. Accurate analysis of a piping system requires a complicated three dimensional finite element model and a computer system with large memory size, while simplified models result in system response prediction with deteriorated accuracy. An efficient analysis model for piping systems is proposed in this study. The proposed model is developed by introducing a joint model which accounts for the behavior of a pipe connection. Pipes are represented by beam elements and the effect of local deformation of pipe connections are replaced by joint element deformations. The proposed model which is as simple and efficient as a beam model can be used to obtain piping system response with accuracy close to that of a finite element model.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.04a
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• pp.325-330
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• 1995

Three types of model concrete with different mix ratios for 1/10 scale reinforced concrete model were made and tested to find the best solution for the simulation of mechanical characteristics of prototype concrete. Scaled reinforcing materials in diameter(D1.8) having similar con-figuration and mechanical properties with commercial deformed bars(D19) were prepared for 1/10 scale model tests of reinforced concrete structures. Two types of model test using D1.8 model reinforcing bars and model concrete, monotonic simple beam test and cyclic cantilever beam test, were performed to ensure and check the similitude of bond behavior between 1/10 scale model and prototype. The test results showed that the flexural behavior of 1/10 scale models can be simulated with accuracy enough for practical use in monotonic and cyclic loading test.