• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.959-963
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• 2006

A three-dimensional elastic blood vessel model with internal diameter variation is considered to investigate internal flow characteristics and effects of structural deformation. Also, computational analyses for both the rigid model and the fully-coupled FSI model have been conducted in order to compare the shear stress, pressure distribution, and flow velocity in detail. A 70% narrowing area of asymmetric blood vessel model was especially investigated to show the versatility of fluid-structure interaction phenomenon. The results reveal that effect of fluid-structure interaction is very important to accurately investigate the flow characteristics of the blood vessel.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1999.11a
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• pp.126-129
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• 1999

Natural ventilation is achieved by air exchanges through multiple openings due to natural pressure variations inside and outside the greenhouse. Wind is the primary driving force making natural ventilation systems very difficult to design properly because of variations in wind velocity and direction. The optimization of these systems for acceptable climate control requires a thorough knowledge of the airflow rates and patterns as related to weather conditions and greenhouse structural details. (omitted)

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.1
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• pp.122-129
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• 2004

Finite element analysis was performed to analyze structural safety of a new heavy-duty direct injection diesel engine. A half section of the in-line 6-cylinder engine was selected as a computational domain. A mapping method was used to project heat transfer coefficients from CFD results of engine coolant flow onto the FE model. The accurate setting of thermal boundary condition on the FE model was expected to result in improved prediction of temperature, cylinder bore distortion, and stresses. Characteristics of high cycle fatigue were investigated by assuming the engine was operated under the following five loading conditions repeatedly; assembly force, assembly force with thermal loading, alternating maximum gas pressure loading at each cylinder combined with assembly force and thermal loading. Distribution of fatigue safety factor was calculated by using it Haigh diagram in which the maximum and the minimum stresses were selected from the five loading cases.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.12 no.3
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• pp.417-426
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• 1999

The some papers which deal with the dynamic instability for shell-like structures under the step load have been published, but there are few papers which treat the essential phenomenon of the dynamic buckling using the phase plane for investigating occurrence of chaos. In nonlinear dynamics, examining the characteristics of attractor on the phase plane and investigating the dynamic buckling process are very important thing for understanding why unstable phenomena are sensitively originated by various initial conditions. In this study, the direct and the indirect snap-buckling of shallow arches considering geometrical nonlinearity are investigated numerically and compared with the static critical load.

• Computational Structural Engineering
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• v.10 no.4
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• pp.337-347
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• 1997

The dynamic responses of highway bridges are varying depending on the features of either traveling vehicles or bridges. In this study, the probabilistic characteristics of dynamic amplification factors of highway bridges due to traveling heavy vehicles have been examined through analytical simulation processes. The truck with tandem axle and tractor with semitrailer are selected as the representative heavy vehicles, which are modeled with three dimensional 7-DOF and 12-DOF models, respectively. The analytical results have been compared with the experimental results of dynamic loading tests and the validity of the analytical models has been examined. Parametric studies on the means and extreme values of amplification factors have been performed with various traffic conditions such as vehicle types, vehicle weights, surface profiles, number of loading vehicles, loading positions, etc.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.22 no.4
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• pp.331-334
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• 2009

In this paper, we present a surface relaxation model in atomistic calculations for thin nanofilms. This surface relaxation model is very simple model which have only two degrees of freedoms to determine the atomic positions of nanofilms. Whereas in conventional molecular statics simulations, the same number of degrees of freedoms at all atom positions are used as unknown variables. In order to prove the reliability of the presented model, we present the results of self-equilibrium strain calculations with the surface parameters obtained from this model.

• Computational Structural Engineering
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• v.7 no.4
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• pp.85-101
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• 1994

A family of variational principles governing the dynamics of laminated plate has been derived using a variationally consistent shear deformable discrete laminated plate theory with particular reference to finite element procedures. The theoretical basis for the derivation is Sandhu's generalized procedure for the variational formulation of linear coupled boundary value problem. As the bilinear mapping to write the operator matrix of the field equations in self-adjoint form, convolution product was employed. Boundary conditions, initial conditions and probable internal discontinuity were explicitly included in the governing functionals. Some interesting extensions and specializations of the general variational principle were presented, which can provide many different finite element formulations for the problem.

• International Journal of High-Rise Buildings
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• v.11 no.4
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• pp.287-300
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• 2022

Unconventional structures are getting more popular in recent days. Large-span roofs are used for many structures, such as airports, stadiums, and conventional halls. Identifying the pressure distribution and wind load acting on those structures is essential. This paper offers a collaborative study of computational fluid dynamics (CFD) simulations and wind tunnel tests for assessing wind pressure distribution for a building with a combined slender curved roof. The hybrid turbulence model, Improved Delayed Detached Eddy Simulation (IDDES), simulates the open terrain turbulent flow field. The wind-induced local pressure coefficients on complex roof structures and the turbulent flow field around the structure were thus calculated based upon open terrain wind flow simulated with the FLUENT software. Local pressure measurements were investigated in a boundary layer wind tunnel simultaneous to the simulation to determine the pressure coefficient distributions. The results predicted by CFD were found to be consistent with the wind tunnel test results. The comparative study validated that the recommended IDDES model and the vortex method associated with CFD simulation are suitable tools for structural engineers to evaluate wind effects on long-span complex roofs and plan irregular buildings during the design stage.

• Journal of Internet Computing and Services
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• v.17 no.6
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• pp.71-79
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• 2016

As computer technology continues to evolve, the Computational Sciences utilized in Physics, Chemistry, Materials Science, and Life Sciences have been attracting more attention. In Korea, to compensate for the drawbacks in Computational Science, students and researchers have been using the EDISON platform. The EDISON platform provides a web portal service for education and research and an environment for addressing complex issues involving five fields, e.g., Computational Fluid Dynamics (CFD), Nanophysics, Computational Chemistry, Structural Dynamics, and Computational Design. As the platform and user scale increase beyond service provision, the need for efficient operation of its currently running data management system is on the rise. In this study, we resolve the data synchronization issues between the existing EDISON platform and web portal. As the EDISON platform is integrated with the web portal, a file management service is implemented to integrate the management of user data and files, which ultimately improves the overall efficiency of file management.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.32 no.4
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• pp.205-213
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• 2019

In the Pohang Earthquake in 2017, considerable damage to non-structural elements, such as ceiling systems, exterior finishes, and curtain walls, was reported; thus, the seismic designs of non-structural elements are important. In this study, the modal characteristics of a ceiling system were investigated through the impact hammer test. The frequency and damping ratio according to the length of the hanger bolt were identified. In addition, collision experiments were conducted to obtain the impact duration for exactly considering the impact effects of the ceiling against a wall or other adjacent elements. Based on the identified dynamics and impact duration of the ceiling system, the seismic responses of the ceiling system were obtained numerically in case of collision. Numerical simulation results show that the impact load tends to increase with the clearance between the ceiling and adjacent elements, and is not correlated with the length of the hanger bolt.