• International Journal of Railway
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• v.6 no.4
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• pp.160-168
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• 2013

A spiral lattice girder-reinforced Bi-block sleeper which has enhanced durability against increasingly growing impact force and vibration by wheel load and improved structural performance while train runs at 350km/h high speed is hereby proposed. The section of a spiral lattice girder has stable and superior structural performance thanks to its confinement effect. To compare and analyze the structural performance of spiral lattice girder-reinforced bi-block sleeper, strain and stress distribution were evaluated after applying same load condition as existing triangular lattice girder-reinforced biblock sleeper, and to compare the structural performance of triangular lattice girder and spiral lattice girder, structural analysis of lattice girder was performed separately. As a result, a spiral lattice girder proved to have had superior structural characteristics to bi-block sleeper, and furthermore as a result of evaluating the fastener interface and constructibility with shape-improved lattice girder, no interference with existing railroad structure was found and in terms of cost efficiency, a spiral lattice girder appeared to be superior to existing lattice girder.

• International Journal of Aeronautical and Space Sciences
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• v.18 no.3
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• pp.450-466
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• 2017

This paper defines the modified effective membrane stiffness, bending stiffness considering the directionally dependent mechanical properties and mode shape function of a composite lattice rectangular plate, which is assumed to be a Kirchhoff-Love plate. It subsequently presents an approximate method of conducting a buckling analysis of the composite lattice rectangular plate with various boundary conditions under uniform compression using the Ritz method. This method considers the coupled buckling mode as well as the global and local buckling modes. The validity of the present method is verified by comparing the results of the finite element analysis. In addition, this paper performs a parametric analysis to investigate the effects of the design parameters on the critical load and buckling mode shape of the composite lattice rectangular plate based on the present method. The results allow a database to be obtained on the buckling characteristics of composite lattice rectangular plates. Consequently, it is concluded that the present method which facilitates the calculation of the critical load and buckling mode shape according to the design parameters as well as the parametric analysis are very useful not only because of their structural design but also because of the buckling analysis of composite lattice structures.

• 한국전산유체공학회:학술대회논문집
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• 2008.03a
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• pp.186-196
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• 2008

The dependence of the rheological properties of blood on shape, aggregation, and deformability of red blood cells (RBCs) has been investigated using hybrid systems by coupling fluid with solid models. We present a simple approach for simulating blood as a multi-component fluid, in which RBCs are modeled as droplets of acquired biconcave shape. We used lattice Boltzmann method (LBM) due to its excellent numerical stability as a simulation tool. The model enables us to control the droplet static shape by imposing non-isotropic surface tension force on the interface between the two components. The use of the proposed non-isotropic surface tension method is justified by the Norris hypothesis. This hypothesis states that the shape of the RBC is due to a non-uniform interfacial surface tension force acting on the RBC periphery. This force is caused by the unbalanced distribution of the lipid molecules on the surface of the RBC. We also used the same concept to investigate the dynamic shape change of the RBC while flowing through the microvasculature, and to explore the physics of the Fahraeus, and the Fahraeus-Lindqvist effects.

• 한국전산유체공학회:학술대회논문집
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• 2008.10a
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• pp.186-196
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• 2008

The dependence of the rheological properties of blood on shape, aggregation, and deformability of red blood cells (RBCs) has been investigated using hybrid systems by coupling fluid with solid models. We present a simple approach for simulating blood as a multi-component fluid, in which RBCs are modeled as droplets of acquired biconcave shape. We used lattice Boltzmann method (LBM) due to its excellent numerical stability as a simulation tool. The model enables us to control the droplet static shape by imposing non-isotropic surface tension force on the interface between the two components. The use of the proposed non-isotropic surface tension method is justified by the Norris hypothesis. This hypothesis states that the shape of the RBC is due to a non-uniform interfacial surface tension force acting on the RBC periphery. This force is caused by the unbalanced distribution of the lipid molecules on the surface of the RBC. We also used the same concept to investigate the dynamic shape change of the RBC while flowing through the microvasculature, and to explore the physics of the Fahraeus, and the Fahraeus-Lindqvist effects.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.1103-1104
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• 2012

• Journal of Korean Association for Spatial Structures
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• v.18 no.4
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• pp.113-121
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• 2018

U-flanged truss beam is composed of u-shaped upper steel flange, lower steel plate of 8mm or more thickness, and connecting lattice bars. Upper flange and lower plate are connected by the diagonal lattice bars welded on the upper and lower sides. In this study the structural experiments on the U-flanged truss beams with various shapes of upper flange were performed, and the flexural and shear capacities of U-flanged truss beam in the construction stage were evaluated. The principal test parameters were the shape of upper flange and the alignment space of diagonal lattice bars. In all the test specimens, the peak loads were determined by the buckling of lattice bar regardless of the upper flange shape. The test results have shown that the buckling of lattice bar is very important design factor and there is no need to reinforce the basic u-shaped upper flange. However, the early lattice buckling occurred in the truss beam with upper steel bars because of the insufficient strength and stiffness of upper chord, and the reinforcement in the upper chord is necessary. The formulae of Eurocode 3 (2005) have presented more exact evaluations of lattice buckling load than those of KBC 2016.

• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.90-93
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• 2009

The use of physics based deformation methods is continuously increasing in computer graphics area such as game and simulation. Many researchers have worked on this method. However, relatively few researchers have considered the development of the user interaction to the 3D objects. This research proposes a physics-based deformation technique using AR (Augmented Reality) environments to enhance user immersion and the effectiveness of the deformation. In the AR circumstances, the physics based deformation should be accomplished in realtime. In the proposed method, we combine RBF (Radial Basis Function) [1] and LSM (Lattice Shape Matching) [2, 3] and apply it to polygonal models for real-time user interaction. The dynamics of the LSM is also calculated to trace the movement of each lattice. Finally these algorithms are implemented in AR environments.

• Journal of Korean Association for Spatial Structures
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• v.23 no.4
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• pp.27-34
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• 2023

In this study, the seismic response characteristics of the three analysis model with or without TMD were investigated to find out the effective dome shape. The three analysis models are rib type, lattice type and geodesic type dome structure composed of space frame. The maximum vertical and horizontal displacements were evaluated at 1/4 point of the span by applying the resonance harmonic load and historical earthquake loads (El Centro, Kobe, Northridge earthquakes). The study of the effective TMD installation position for the dome structure shows that seismic response control was effective when eight TMDs were installed in all types of analysis model. The investigation of the efficiency of TMD according to dome shape presents that lattice dome and geodesic dome show excellent control performance, while rib dome shows different control performance depending on the historical seismic loads. Therefore, lattice and geodesic types are desirable for seismic response reduction using TMD compared to rib type.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.116-117
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• 2006

I-D ZnO nanostructures were fabricated by thermal evaporation method on Si(100), GaN and $Al_2O_3$ substrates without a catalyst at the reaction temperature of $700^{\circ}C$. Only pure Zn powder was used as a source material and Ar was used as a carrier gas. The shape and growth direction of synthesized ZnO nanostructures is determined by the crystal structure and the lattice mismatch between ZnO and substrates. The ZnO nanostructure on Si substrate were inclined regardless of their substrate orientation. The origin of ZnO/Si interface is highly lattice-mismatched and the surface of the Si substrate inevitably has the $SiO_2$ layer. The ZnO nanostructure on the $Al_2O_3$ substrate was synthesized into the rod shape and grown into particular direction. For the GaN substrate, however, ZnO nanostructure with the honeycomb-like shape was vertically grown, owing to the similar lattice parameter with GaN substrate.

• Journal of the Korea Concrete Institute
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• v.20 no.6
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• pp.705-712
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• 2008

This study carried out simulation for structural layout design for concrete structures by using the models of the ground structure method. The micro lattice truss is modeled as assemblage of a number of unit cells. The progress of analysis repeat to undergo finite element analysis to feed-back results of stress to the stiffness of each member. Through the repeated this analysis, truss model is represented to form the topological materials and the structural shape with the use of the local stress condition without mathematical optimum tools. It is successful to analyse the shape-layout problem as numerical samples on the lattice truss model.