• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.2
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• pp.111-123
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• 2006

In the design of bridges, exact evaluation of traffic loading is very important for the safety and maintenance of bridges. In general, traffic loading is represented by live load (including impact load) and fatigue load. For exact evaluation of traffic loading, it is important to get reliable and comprehensive truck data including the traffic and weight information. It requires the development of Bridge Weigh-In-Motion (BWIM), which measures the truck weights without stopping the traffic. Objectives of the study is (1) to develop the BWIM system, (2) to verified the system in bridges in Highways.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.321-326
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• 2007

The joined-wing is a new concept of the airplane wing. The fore-wing and the aft-wing arc joined together in the joined-wing. The range and loiter are longer than those of a conventional wing. The joined-wing can lead to increased aerodynamic performances and reduction of the structural weight. The structural behavior of the joined-wing has a high geometric nonlinearity according to the external loads. The gust loads are the most critical loading conditions in the structural design of the joined-wing. The nonlinear behavior should be considered in the optimization of the joined-wing. It is well known that conventional nonlinear response optimization is extremely expensive: therefore, the conventional method is almost impossible to use in large scale structures such as the joined-wing. In this research, geometric nonlinear response structural optimization is carried out using equivalent loads. Equivalent loads are the load sets which generate the same response field in linear analysis as that from nonlinear analysis. In the equivalent loads method, the external loads are transformed to the equivalent loads (EL) for linear static analysis, and linear response optimization is carried out based on the EL.

• Geomechanics and Engineering
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• v.30 no.3
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• pp.313-324
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• 2022

With the development of the economy, people's utilization of underground space are also improved, and a large number of cities have begun to build subways to relieve traffic pressure. The choice of subway station construction method is crucial. If an inappropriate construction method is selected, it will not only waste costs but also cause excessive deformation that may also threaten construction safety. In this paper, a subway station construction scheme selects model based on the AHP-fuzzy comprehensive evaluation. The rationality of the model is verified using numerical simulation and monitoring measurement data. Firstly, considering the economy and safety, a comprehensive evaluation system is established by selecting several indicators. Then, the analytic hierarchy process is used to determine the weight of the evaluation index, and the dimensionless membership in the fuzzy comprehensive evaluation method is used to evaluate the advantages and disadvantages of the construction method. Finally, the method is applied to Liaoyang east road station of Qingdao metro Line 2, and the results are verified by numerical simulation and monitoring measurement data. The results show that the model is scientific, practical and applicable.

• Proceeding of KASS Symposium
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• 2008.05a
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• pp.61-65
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• 2008

A 4-story reinforced concrete structure built above an underground parking garage shows some slab deflections, and the deflections of the concrete floor slabs are proposed to be alleviated by the application of light-weight topping material in conjunction with localized strengthening of the slabs. The application of light-weight concrete topping on the existing slab has been simulated and its performance to anticipated loads has been analyzed. The application of light-weight topping material imposes additional weight on the exiting floor slabs. This added weight on the existing slabs causes over-stressing of the slabs. This over-stressing can be alleviated by enhancing the load carrying capacity of the existing slabs. Additional load carrying capacity in the existing slabs can be developed by localized strengthening of the slabs utilizing techniques such as the application of fiber-reinforced composites on the bottom surface of the slabs, and application of fiber-reinforced composites adequately complements the capacity of the existing slabs to bear the additional load imposed by light-weight leveling material. Additional moments in the beam and columns induced by the application of the light-weight topping material were tabulated and compared with capacity. The moment D/C ratios of the beam and columns are well the range of acceptable limits, and the beam and columns are not overstressed by the application of the surcharge.

• Journal of the Korean Society of Propulsion Engineers
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• v.16 no.5
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• pp.81-88
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• 2012

Turbopump is a key component in liquid rocket engines, and reducing weight while maintaining structural safety is one of the major concerns of turbopump designers. To reduce the weight aluminium alloy castings instead of steel casings are introduced. The casting process is especially useful for enhancement of productivity and for reduction of product costs. But, since castings are used in space vehicle engines, reliability cannot be compromised. Therefore, proper design, production process and thorough investigation should be performed to ensure structural integrity. In this study inlet casings for a fuel pump were casted with A356.0-T6 alloy and using one of them a burst test was conducted to ensure structural integrity. Structural analysis is performed for simulation, and with multiple strain gages strains are measured and compared with predictions.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.16 no.2
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• pp.133-140
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• 2003

The sandwich plate has been widely used as an efficient structural member because it has high strength-to-weight and high stiffness-to-weight ratios. To properly design the aluminum extrusion plate , it is necessary to analyze structural behaviors of the extrusions, however, the aluminum extrusions have been rarely studied until now. In the optimization process through numerous iterative calculations, finite element analysis of the sandwich plate with hollow core section requires a considerable amount of computation time and cost. In this paper, the aluminum extrusion plate with truss-core is transformed into an equivalent homogeneous orthotropic plate with appropriate elastic constants. The procedure to evaluate accurate equivalent elastic constants is also established. Using these elastic constants, simple theoretical formulas of the stresses and deflection are proposed in case of the simply-supported orthotropic thick plate under uniform pressure. Through the comparison with the results by commercial FEM code(ANSYS), it is verified that the proposed simpified formula has a good efficiency and accuracy.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.1
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• pp.190-196
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• 2009

This study proposes a structural design method for the upper control arm installed at the rear side of a SUV. The weight of control arm can be reduced by applying the design and material technologies. In this research, the former includes optimization technology, and the latter the technologies for selecting aluminum as a steel-substitute material. Strength assessment is the most important design criterion in the structural design of a control arm. At the proto design stage of a new control arm, FE (finite element) analysis is often utilized to predict its strength. This study considers the static strength in the optimization process. The inertia relief method for FE analysis is utilized to simulate the static loading conditions. According to the classification of structural optimization, the structural design of a control arm is included in the category of shape optimization. In this study, the kriging interpolation method is adopted to obtain the minimum weight satisfying the strength constraint. Optimum designs are obtained by ANSYS WORKBENCH and the in-house program, EXCEL-kriging program. The optimum results determined from the in-house program are compared with those of ANSYS WORKBENCH.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.616-623
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• 2012

Turbopump is a key component in liquid rocket engines, and reducing weight while maintaining structural safety is one of the major concerns of turbopump designers. To reduce the weight aluminium alloy castings instead of steel casings are introduced. The casting process is especially useful for enhancement of productivity and for reduction of product costs. But, since castings are used in space vehicle engines, reliability cannot be compromised therefore proper design, production process and thorough investigation should be performed to ensure structural integrity. In this study inlet casings for a fuel pump are casted with A356.0-T6 alloy and using one of them a burst test is conducted to ensure structural integrity. Structural analysis is performed for simulation, and with multiple strain gages strains are measured and compared with predictions.

• Corrosion Science and Technology
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• v.22 no.3
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• pp.201-213
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• 2023

Corrosion management of an aircraft and its engine relies on rinsing and cleaning using tap water. Few studies have reported effects of tap water species on corrosion behaviors of structural materials. In this study, a series of experiments were conducted based on the design of experiment. Solutions with different levels of chloride and sulfate ions were prepared using a full factorial design. Two structural materials (aluminum alloy and steel) were used for an alternate immersion test. Weight loss was then measured. In addition, a silver specimen was utilized as a sensor for chloride deposition measurement. The silver specimen was examined using the electrochemical reduction method, XPS, and SEM-EDS. Surface analysis revealed that levels of chloride and sulfate ions were sufficient for the formation of silver chloride and silver surface. Statistical analysis of weight loss and chloride deposition rate showed significant differences in measured values. Concentration of chloride ions greatly affected corrosion behaviors of structural materials. Sulfate ion hindered the adsorption reaction. These results emphasize the importance of controlling ion concentration of tap water used for cleaning and rinsing an aircraft.

• Korean Journal of Human Ecology
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• v.20 no.5
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• pp.1025-1034
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• 2011

The purpose of this study was to examine the evaluation of fabric characteristics on the drapability, texture image and preference of blouse fabrics, and to analyze the effects of the texture image, objective and subjective drapability on the preference. As specimen, silk and polyester fabrics were collected. 52 female subjects evaluated 16 specimens with semantic differential scale of 18 fabric image and 20 sensibility. Data were analyzed through factor analysis, pearson correlational coefficient using spss win 12.0. For the evaluation, structural characteristics such as fiber contents, weave type, weight and thickness were analyzed. The results were as follows: The evaluation results of objective and subjective drapability showed differences. Sensory image factors of blouse fabrics were 'surface smoothness', 'elasticity', 'weight' and 'flexibility'. Sensibility image factors were 'elegance', 'classic', 'characteristic' and 'mannish'. 'Elegance', 'classic' and 'characteristic' of sensibility images showed high correlation with 'surface smoothness' and 'elasticity' of sensory image, also 'mannish' of sensibility image showed significant correlation with 'weight' of sensory image. The significant fabric characteristics affecting objective drapability were density, weight, thickness. The significant texture image factors affecting objective drapability were 'weight', 'flexibility' of sensory image and 'elegance' of sensibility image. On the other hand, the significant factors affecting subjective drapability were thickness of fabric characteristics and 'elegance', 'characteristic', 'mannish' of sensibility images. 'Elegance', 'characteristic' and 'classic' of sensibility image, 'elasticity' of sensory image and subjective drapability affected on the purchase preference.