• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.945-948
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• 2017

A valve used in a high temperature and pressure condition for high-speed vehicle application was developed for fuel supply and cooling system. For weight reduction purpose, the size outline of valve was optimized based on its performance and operating environment. And the rigidity design was adopted by minimizing uses of sealing parts to prevent leakages. Also, A fluid analysis was performed to derive the optimized internal flow path design in consideration of minimized pressure drop. Finally, the valve performance was verified by installing the valve into the test equipment which enable to simulate endothermic fuel of high temperature in high-speed vehicle.

• Steel and Composite Structures
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• v.20 no.3
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• pp.545-569
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• 2016

Stiffeners have widely been used in lateral load resisting systems to improve the buckling stability of shear panels in steel frames. However, due to major differences between plate girders and steel plate shear walls (SPSWs), use of plate girder equations often leads to uneconomical and, in some cases, incorrect design of stiffeners. Hence, this paper uses finite element analysis (FEA) to describe the effect of the rigidity and arrangement of stiffeners on the buckling behavior of plates. The procedures consider transverse and/or longitudinal stiffeners in various practical configurations. Subsequently, curves and formulas for the design of stiffeners are presented. In addition, the influence of stiffeners on the inward forces subjected to the boundary elements and the tension field angle is investigated as well. The results indicate that the effective application of stiffeners in SPSW systems not only improves the structural behavior, such as stiffness, overall strength and energy absorption, but also leads to a reduction of the forces that are exerted on the boundary elements.

• Steel and Composite Structures
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• v.22 no.6
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• pp.1217-1238
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• 2016

Mega composite structure systems have been widely used in high rise buildings in China. Compared to other structures, this type of composite structure systems has a larger cross-section with less weight. Concrete filled steel tubular (CFST) laced column to box-beam connections are gaining popularity, in particular for the mega composite structure system in high rise buildings. To enable a better understanding of the destruction characteristics and aseismic performance of these connections, three different connection types of specimens including single-limb bracing, cross bracing and diaphragms for core area of connections were tested under low cyclic and reciprocating loading. Hysteresis curves and skeleton curves were obtained from cyclic loading tests under axial loading. Based on these tested curves, a new trilinear hysteretic restoring force model considering rigidity degradation is proposed for CFST laced column to box-beam connections in a mega composite structure system, including a trilinear skeleton model based on calculation, law of stiffness degradation and hysteresis rules. The trilinear hysteretic restoring force model is compared with the experimental results. The experimental data shows that the new hysteretic restoring force model tallies with the test curves well and can be referenced for elastic-plastic seismic analysis of CFST laced column to composite box-beam connection in a mega composite structure system.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.9
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• pp.946-957
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• 2012

The objective of this paper is to investigate into the development of a thin flat panel photo-bioreactor case with characteristics shapes. The thin flat panel photo-bioreactor case was designed to be manufactured from a plastic thermoforming process. A proper design with a relatively high rigidity was obtained through the structural analyses for different designs of the photo-bioreactor case. The thermoforming analyses were performed. From the results of the thermoforming analyses, a proper forming condition and the formability of the designed plastic photo-bioreactor case were estimated. The thermoforming moulds for the flat panel photobioreactor cases were manufactured. The thermoforming experiments were performed to examine the manufacturability of the designed flat panel photo-bioreactor cases. From the results of the thermoforming experiments, it was shown that thin flat panel photo-bioreactor cases with characteristic shapes can be manufactured from the designed thermoforming mould and process.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.9
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• pp.2179-2182
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• 2009

Recently, the development of new structural model in optical mechanical system is required to be started from the conceptual design with low cost, high performance and quality. In this point, a structural-topological shape of system concerned with conceptual design of mechanical structure has a great effect on performance of the system such as the structural rigidities and weight reduction. In this paper, the optimization design methodologies are presented in the design stages of large optical structure. First, using topology optimization, we obtain the optimal layout and the reinforcement of structure, and then carry out the detail designs using size optimization and multidisciplinary optimization technique. As an example, these methods were applied to the design of large mirror structure.

• Journal of the Korean Magnetic Resonance Society
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• v.20 no.3
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• pp.76-81
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• 2016

Copper is an elemental ion in living organisms. CopP from Helicobacter Pylori (HpCopP) is a copper(I)-binding protein and was suggested as regulator of copper metabolism in vivo. Previously, the metal binding property of HpCopP for Ag(I), Cu(I), and Cu(II) as well as the tertiary structure of HpCopP was shown. In this study, the dynamic profiles of HpCopP depending on metal binding were studied using ${^1H}-^{15}N$ steady-state NOE analysis. The heteroNOE experiment was performed for apo-CopP or metal-bound CopP. The obtained NOE values were analyzed and compared to figure out the effect of metals on the structural flexibility of HpCopP. As a result, Ag(I) and Cu(I) ions improved the rigidity of the structure while Cu(II) ion increased the flexibility of the structure, suggesting the oxidation of the CXXC motif decreases the structural stability of HpCopP.

• Steel and Composite Structures
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• v.6 no.3
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• pp.237-255
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• 2006

This paper presents a novel analytical formulation for the analysis of composite beams with partial shear interaction stiffened by a bolted longitudinal plate accounting for time effects, such as creep and shrinkage. The model is derived by means of the principle of virtual work using a displacement-based formulation. The particularity of this approach is that the partial interaction behaviour is assumed to exist between the top slab and the joist as well as between the joist and the bolted longitudinal stiffening plate, therefore leading to a three-layered structural representation. For this purpose, a novel finite element is derived and presented. Its accuracy is validated based on short-and long-term analyses for the particular cases of full shear interaction and partial shear interaction of two layers for which solutions in closed form are available in the literature. A parametric study is carried out considering different stiffening arrangements to investigate the influence on the short-and long-term behaviour of the composite beam of the shear connection stiffness between the concrete slab and the steel joist, the stiffness of the plate-to-beam connection, the properties of the longitudinal plate and the concrete properties. The values of the deflection obtained from the finite element simulations are compared against those calculated using the effective flexural rigidity in accordance with EC5 guidelines for the behaviour of elastic multi-layered beams with flexible connection and it is shown how the latter well predicts the structural response. The proposed numerical examples highlight the ease of use of the proposed approach in determining the effectiveness of different retrofitting solutions at service conditions.

• Bulletin of the Society of Naval Architects of Korea
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• v.13 no.3
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• pp.11-19
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• 1976

Grillages are abundant in ship structures and in many other types of structures such as bridges and building floors. Clarkson has shown that plated grillages can be satisfactorily analyzed as gridworks if an appropriate effective breadth is taken into account. Also, it has previously been pointed out, by Nielsen, that grillage calculations could be simplified by use of the Laplace transformation. In this paper, it is assumed that the torsional rigidity of the members and axial load are negligible, also that girders have the same scantling and spacing each other and so stiffeners do. Then the grillages composed of both-end-fixed girders and both-end-hinged stiffeners, which are subjected only to uniform normal loads are investigated. The calculus of variation is used to set up the differential equations and the Laplace transformation is applied to solve the differential equations. The program has been tested by FACOM 28 and the results show good agreements with those by the STRESS, which was developed in M.I.T.. The amount of the data input and computing time are much less than those of the STRESS. But this program has so much restrictions that it is urgent to extend the program to the grillage problems of arbitrary loading and boundary conditions.

• Journal of the Korean Institute of Educational Facilities
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• v.26 no.5
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• pp.25-36
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• 2019

School gymnasium is a multi-purpose large space building for various events and physical education activities, and is a facility that requires an approach to the desirable structural design, besides mechanical problems of structure against loads. For the integrated structure design concerning the architectural features, the major considerations of gymnasium planning that are the internal and external shape of the gymnasium, the space scale with structure members, the structural efficiency by members weight reduction and openness of the gymnasium space will have to take into account in the structural planning. From this point of view, the several cases of the school gymnasium were investigated and the parametric analyses were performed to the models using the various structural system. The parameters were the composition elements of structure system that are profile of structure, rigidity of member, connection and anchorage and stability. At the result, It was presented that the profile of structure member was the most influential factor to structural efficiency and the effect of the form and space of gymnasium. Also the design informations of structure design having the various feature of form and space were presented for the initial gymnasium planning.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.10
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• pp.59-67
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• 2020

Polycarbonate thermoplastic composite materials are anisotropic and exhibit physical properties in the longitudinal direction. Therefore, the physical properties depend on the type and direction of reinforcements. The thermal conductivity, electrical conductivity, and resin impregnation can be controlled by adding carbon nanotubes to polycarbonate resin. However, the carbon fiber used as a reinforcing material is expensive, interfacial adhesion issues occur, and simulation values are different from actual values, making it difficult to perform mathematical analysis. However, carbon nanotubes have advantages such as light weight, rigidity, impact resistance, and reduced number of parts compared to metals. Due to these advantages, it has been applied to various products to reduce weight, improve corrosion resistance, and increase impact durability. As the content of carbon nanotubes or carbon fibers increases, the mechanical properties and antistatic and electromagnetic shielding performance improve. It is expected that the amount of carbon nanotubes or carbon fibers can be optimized and applied to various industrial products.