• Steel and Composite Structures
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• v.38 no.4
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• pp.381-397
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• 2021

Based on the spatial substructure hybrid simulation test (SHST) method, the seismic performance of a high-strength steel composite K-eccentrically braced frame (K-HSS-EBF) structure system is studied. First, on the basis of the existing pseudostatic experiments, a numerical model corresponding to the experimental model was established using OpenSees, which mainly simulated the shear effect of the shear links. A three-story and five-span spatial K-HSS-EBF was taken as the prototype, and SHST was performed with a half-scale SHST model. According to the test results, the validity of the SHST model was verified, and the main seismic performance indexes of the experimental substructure under different seismic waves were studied. The results show that the hybrid simulation results are basically consistent with the numerical simulation results of the global structure. The deformation of each story is mainly concentrated in the web of the shear link owing to shear deformation. The maximum interstory drifts of the model structure during Strength Level Earthquake (SLE) and Maximum Considered Earthquake (MCE) meet the demands of interstory limitations in the Chinese seismic design code of buildings. In conclusion, the seismic response characteristics of the K-HSS-EBFs are successfully simulated using the spatial SHST, which shows that the K-HSS-EBFs have good seismic performance.

• Wind and Structures
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• v.23 no.5
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• pp.421-447
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• 2016

Wind-induced and earthquake-induced excitations on tall structures can be effectively controlled by Tuned Liquid Damper (TLD). This work presents a numerical simulation procedure to study the performance of tuned liquid tank- structure system through ${\sigma}$-transformation based fluid-structure coupled solver. For this, a 'C' based computational code is developed. Structural equations are coupled with fluid equations in order to achieve the transfer of sloshing forces to structure for damping. Structural equations are solved by fourth order Runge-Kutta method while fluid equations are solved using finite difference based sigma transformed algorithm. Code is validated with previously published results. The minimum displacement of structure is observed when the resonance condition of the coupled system is satisfied through proper tuning of TLD. Since real-time excitations are random in nature, the performance study of TLD under random excitation is also carried out in which the Bretschneider spectrum is used to generate the random input wave.

• Journal of the Korea Institute of Military Science and Technology
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• v.18 no.4
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• pp.369-375
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• 2015

In this paper, transparent circuit analog radar absorbing structure with angular stability for stealth aircraft canopy was proposed and designed. To obtain wideband electromagnetic absorption, optical transparency and smaller thickness, we proposed the novel FSS(Frequency Selective Surface) for X-band and implemented the resistive FSS and PEC(Perfect Electric Conductor) plane using ITO(Indium Thin Oxide) coating with optical transmissivity of 90 %. Reflection loss characteristics for different incident angles of both TE(Transverse Electric) and TM(Transverse Magnetic) polarizations are presented through simulations. We then fabricated the proposed structure to verify the simulation results. The comparisons between the simulation and measured results show good agreements. The results also show that the proposed radar absorbing structure can provide better frequency stability for different incidence angles and polarizations as well as optical transparency. We can apply this proposed structure to the canopy of stealth aircraft and other stealth applications for visible transparency.

• Journal of the Korean Society of Visualization
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• v.18 no.3
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• pp.35-41
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• 2020

We conduct numerical simulations of the interaction of a deformable structure with two-phase compressible flow. The finite volume method (FVM) is used to simulate fluid phenomena including a shock wave, a gas bubble, and the deformation of free surface. The deformation of a floating structure is computed with the finite element method (FEM). The compressible two-phase volume of fluid (VOF) method is used for the generation and development of a cavitation bubble, and the immersed boundary method (IBM) is used to impose the effect of the structure on the fluid domain. The result of the simulation shows the generation of a shock wave, and the expansion of the bubble. Also, the deformation of the structure due to the hydrodynamic loading by the explosion is identified.

• Structural Monitoring and Maintenance
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• v.5 no.2
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• pp.297-311
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• 2018

Plate and shell structure is widely applied in engineering, i.e. building roofs, aircraft wings, ship platforms, and satellite solar arrays. Its vibration problem has become increasingly prominent due to the tendency of lightening, upsizing and flexibility. As a new smart material with great actuating force and toughness, macro-fiber composite (MFC) is composed of piezoelectric fiber and epoxy resin basal body, which can be directly pasted onto the surface of plate and shell and is suitable for vibration control. This paper deduces the actuation equation of MFC coupled plate in different boundary conditions, an equivalent finite element modeling method is proposed which uses MFC actuating force as the applied excitation, and on this basis the active control simulation and experiment of MFC over plate and shell structure vibration are accomplished. The results indicate that MFC is able to implement effective control over plate and shell structure vibration in multi-band range. The comparison between experiment and simulation proves that the actuation equation deduced herein, effective and practicable, can be applied into the simulation calculation of MFC vibration control over plate and shell structure.

• The Journal of Korean Association of Computer Education
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• v.11 no.1
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• pp.75-83
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• 2008

The prior data structure coursewares have been limited to using a simple screen structure with text, pictures or plain animation so that they have been failed to promote favorable interaction between learners and instructors, and unnecessarily charges the screen. In order to overcome these problems, this paper provides an applet-based simulation environment which enables learner to operate and control the data structure operation with their own data, therefore, the learners can actively and positively participate in a study with this courseware. The instructors can easily deliver the education contents to the learners by using web simulation suitable for IT education media. Also, the courseware can offer a class feedback and required data for students estimation by recording a log.

• Journal of Korean Institute of Industrial Engineers
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• v.11 no.1
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• pp.21-32
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• 1985

Presented in this paper is a procedure of developing graphical simulation software for planning robot welding processes. Welding is by far the highest application area for industrial robots, and it has been in great need of such a simulator in designing robot work cells, in justifying the economics of robot welding and in planning robotized welding operations. The model of a robot welding cell consists of four components: They are an welding structure which is a collection of plates to be welded, a positioner to hold the welding structure, a robot with a weld torch, and a set of welding lines (in case of arc welding). Welding structure is modeled by using the reference plane concept and is represented as boundary file which is widely used in solid modeling. Robot itself is modeled as a kinematic linkage system. Also included in the model are such technical constraints as weaving patterns and inclination allowances for each weld joint type. An interactive means is provided to input the welding structure and welding lines on a graphics terminal. Upon completion of input, the program displays the welding structure and welding lines and calculates the center of mass which is used in determining positioner configurations. For a given positioner and robot configuration, the welding line segments that can be covered by the robot are identified, enabling to calculate the robot weld ratio and cycle time. The program is written in FORTRAN for a VAX computer with a Tektronix 4114 graphic terminal.

• Journal of Korea Game Society
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• v.9 no.4
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• pp.97-106
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• 2009

In this paper, a realtime approach to the simulation of virtual paper with an adaptive mesh structure is proposed. The proposed method can be applied to arbitrary triangular mesh structures and efficiently produces wrinkles and creases on the paper surface with stable numerical integration and deformation-based mesh refinement. In order to plausibly represent the crumples on the paper object, we employed an adaptive mesh structure with breakable springs. Because the adaptive structure continuously inserts or removes vertices and edges to or from the mesh structure, the conservation of the mass and the momentum should be carefully taken into account for the plausible simulation of the virtual paper. The proposed method produced plausible animation of paper-like thin shell in realtime environments.

• Journal of Ocean Engineering and Technology
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• v.26 no.1
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• pp.17-26
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• 2012

A coupled analysis of a floating crane barge with a crane wire and hanging structure is carried out in thetime domain. The motion analysis of the crane barge is based on the floating multi-body dynamics, and thecrane wire is modeled as a simple spring tension. The hanging structure is assumed to be a rigid body with 3 degree-of-freedom translational motion. In this study, numerical simulations were conducted at three different stages. First, the developed code was validated by comparing the time-domain motion response of a crane barge with the frequency-domain results. Then, a coupled analysis of a crane barge and simple structure hanging by the crane wire was performed using the present scheme. The motion response and wire tension from the present calculations are compared with the results of OrcaFlex. The agreement between the two sets of results isfairly good. Last, lowering simulations in regular and irregular waves were conducted considering buoyancy changes in the hanging structure. The effects of the wave conditions, structure's weight, wire length, and lowering speed on the wire tension are considered.

• Journal of Ocean Engineering and Technology
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• v.27 no.1
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• pp.93-101
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• 2013

The incident bore impact loads acting on a tall structure is simulated using the refined Moving Particle Simulation (MPS) method. The particle method is more feasible and effective than conventional grid-based methods for the violent free-surface problems. In the present study, the simulation results for the temporal change of the hydrodynamic force on the structure and longitudinal velocity component around the structure are compared with the experiments (Radd and Bidoae, 2005). And the mitigation effects by installation of various obstacles in front of the main structure are investigated and discussed form the simulation results.