• The Journal of the Acoustical Society of Korea
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• v.10 no.2
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• pp.68-77
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• 1991

• The Journal of the Acoustical Society of Korea
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• v.10 no.3
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• pp.51-58
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• 1991

• Journal of the Korean Society for Aviation and Aeronautics
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• v.20 no.3
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• pp.44-50
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• 2012

The noise reduction is important one of considerations in the process of a civil aircraft development program. External noise sources are classified into an air-born source and a structure-born source. Among these noise sources, the most affected noise source into a cabin is the air-born noise source from an engine or propeller. The external noise is transmitted into the cabin through the fuselage structure of airplane which are composed of an fuselage structure, an interior trim panel and an acoustic insulation layer between an fuselage structure and an interior trim panel. Therefore, appropriate fuselage structure and acoustic insulation layer is very important to reduce the internal noise level. In this paper, the vibro-acoustic coupled analysis of the cabin noise of the 80~90 seats regional turboprop aircraft is carried out to validate the acoustic analysis method using Direct BEM and FEM. The sound pressure level onto the fuselage skin is acquired by fan-source noise analysis using BEM, and which sound pressure is used as acoustic noise source in vibro-acoustic noise analysis for cabin noise analysis using FEM.

• Journal of the Korean Society of Clothing and Textiles
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• v.22 no.5
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• pp.565-574
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• 1998

The purpose of the study was to determine the effect of air velocity on the thermal resistance of wool ensembles. Three suits for men with different weaving structure and density were made with the same design and size for the study. In addition, Y-shirt, underwear, and socks were prepared for constructing the ensembles. Thermal insulation of air layer and 3 ensembles were measured by using thermal manikin in environmental chamber controlled at 2$0^{\circ}C$ and 65% RH with various air velocity. The results were as follows: 1. Thermal resistance of air layer was 0.079 m2.$^{\circ}C$/W with no air velocity(less than 0.2m/sec). 2. Thermal resistance of air layer decreased with increasing the air velocity rapidly. When the air velocity was 0.25 and 2.89 m/sec, the decreasing rate was 15% and 61%, respectively compared with no air velocity. 3. While there was little difference among the effective thermal insulation of 3 ensembles having different weaving structure and density with no air velocity, there was sharp difference among them when the air velocity increased. That is, the decreasing rate of effective thermal insulation of the ensemble which has higher air permeability was higher. 4. The decreasing rates of the effective thermal resistances of plain, twill and satin ensemble were 61, 54, and 49%, respectively when the air velocity was 2.89 m/sec which was a maximum air velocity in this study.

• Journal of Korean Association for Spatial Structures
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• v.23 no.3
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• pp.35-43
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• 2023

This study aims to evaluate the structural safety of a structural thermal barrier, installed inside the structure of a building and performed the role of a load-bearing element and an insulation simultaneously, contributing to the realization of net-zero buildings. To ensure the reliability of the analysis model, the analysis results derived from LS-DYNA were compared with the experimental results. Based on the results shown through the flexural experiment, the reliability of the thermal cross-section insulation structure model for slabs was validated. In addition, the effect of the UHPC block on the load support performance and its contribution to vertical deflection was verified.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.1
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• pp.79-87
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• 2018

The purpose of this study was to analyze factors influencing insulation performance of inorganic Autoclaved Lightweight Concrete(ALC) sandwich wall panels with the application of shear connectors. To analyze the effect of shear connectors on the thermal performance of sandwich wall panels, heat transfer analysis was conducted by using the three-dimensional heat transfer simulation software. Four types of shear connector such as Pin, Clip, Grid, and Truss were selected for insulation performance analysis. Thermal bridge coefficient was calculated by varying typical panel thickness and shear connector thickness and materials such as steel, aluminum, and stainless steel. The results showed that Grid and Truss type widely distributed along the section of sandwich wall panel had a great influence on the thermal bridge coefficient by changing the influence factors. Based on the results of thermal and structural performance analysis, effective heat transmission coefficient of the sandwich wall panel satisfying the passive house insulation criteria was calculated. As a result, it was found that heat transmission coefficient was increased from $0.132W/m^2{\cdot}K$ to $0.141{\sim}0.306W/m^2{\cdot}K$ depending on the shear connector types and materials. In the majority of cases, the passive house insulation criteria was not satisfied after using shear connectors. The results of this study were likely to vary according to how influence factors were set, but it is important to apply the methods that reduce the thermal bridge when there would be a possibility of greatly affecting the insulation performance.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1994.05a
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• pp.46-49
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• 1994

In order to investigate possibility of CV cable diagnosis technique, residual insulation characteristics of .long - term serviced 0.6 kV CV Cable are examined by DC leakage current residual voltage tensile strength, cross1inking density and AC & impulse breakdown. Also effect of cable structure and water tree are reported

• Journal of the Korean Institute of Gas
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• v.17 no.2
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• pp.85-89
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• 2013

The purpose of the development of KC-1 LNG cargo containment system is reduction in royalty and increase in competitiveness of shipbuilding industry. An assessment of structure safety for LNG cargo containment system under sloshing load due to ship motion has become an important design element. The ideal way is to implement fully interaction of the fluid domain and the cargo containment system. However the irregular sloshing pressure were idealized in the form of a triangular wave for safety assessment because the fluid- structure interaction analysis is taken the extensive computation time and difficult to ensure the accuracy of the results. In this study, the sloshing load was assumed to be a triangular wave with a maximum pressure of 10 bar during 15/1000 seconds. In the analytic results, the basic insulation panel of KC-1 LNG cargo containment system was assessed to be structurally safe for sloshing load.

• Journal of the Korean Institute of Gas
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• v.8 no.4 s.25
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• pp.1-7
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• 2004

In this paper, the FE analysis has been presented for the leakage safety of the membrane LNG storage tank based on the thermal resistance effects between the insulation panel and prestressed concrete structure. The FEM calculated results show that the leakage safety of plywood and polyurethane materials does not guarantee any more due to a strength failure of the insulation structure. But the PC structure of outer tank may delay leaked LNG of 10 days even though the inner tank and insulation structure are simultaneously failed. This means that the membrane LNG storage tank may be safe because of the stiffness of the outer tank.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.513-517
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• 2004

This study aims to evaluate factors of floor structure influencing to the floor impact sound. For this reasons, we measured the vibration of floor and the floor impact sound in moment flame structure. The main results from this study are that slab area and thickness are critical factors of the floor impact sound and aspect ratio slab is not verified in flor impact sound.