• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2013년도 추계 학술논문 발표대회
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• pp.46-47
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• 2013

In this research, it is investigated strength development by replacement ratio of mineral admixture contents, types of superplastisizer and strength improvement material contents based on industrial byproduct to expand use of low cement concrete for typical floor.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.548-553
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• 2008

Low Floor buses have no steps to get on or get off the main cabin to provide the old and the handicapped with easy access. The car body for the low floor bus was designed to consider Korean physical standard, passenger capacity (standee, seated, handicapped), arrangement of vehicle components, and bus law or regulations. It was designed as an one body, without any reinforcement armature, which has light-weight sandwich constructions with glass epoxy skins, aluminum honeycomb cores and inner-frames. In this paper, torsion rigidity of the designed car body was evaluated and compared with that of a car body with reinforcement armatures in the cabin. Finite element method verified that the designed car body without reinforcement armatures could satisfy requirements of torsion rigidity.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.269-274
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• 2004

The aims of this study were to Investigate the floor impact noise isolation performance of floating floor with isolation materials and propose the improvement direction of floor impact noise measurement method and evaluation classes using impact ball. Reduction of light-weight impact sound pressure level can be achieved by the finishing materials, such as vinyl finishing material and wooden flooring with isolation materials. Floor impact noise Isolation material which satisfy the properties of the floor impact noise isolation materials cause resonance in the low frequency band and worsen heavy-weight impact sound pressure level. Heavy-weight impact sound level can be reduced by using noise reduction flooring, ceiling and increase of slab thickness. Strong impact force in low frequency bang below 63Hz of bang machine is not similar to human impact source and causes some problem in evaluating heavy-weight impact noise but heavy-weight impact noise measurement and evolution using impact ball which is very similar to human impact is more reliable than bang machine. Correction value on the background noise and sensitivity of residents should be considered on the floor impact noise evaluation classes.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.1451-1452
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• 2010

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.1449-1450
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• 2010

• Structural Engineering and Mechanics
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• 제75권3호
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• pp.377-387
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• 2020

Modern long-span floor system typically possesses low damping and low natural frequency, presenting a potential vibration sensitivity problem induced by human activities. Field test and numerical analysis methods are available to study this kind of problems, but would be inconvenient for design engineers. This paper proposes a simplified method to determine the acceleration amplitudes of long-span floor system subjected to walking or running load, which can be carried out manually. To theoretically analyze the acceleration response, the floor system is simplified as an anisotropic rectangular plate and the mode decomposition method is used. To facilitate the calculation of acceleration amplitude a_P, a coefficient α_wmn or α_Rmn is introduced, with the former depending on the geometry and support condition of floor system and the latter on the contact duration t_R and natural frequency. The proposed simplified method is easy for practical use and gives safe structural designs.

• 한국기계기술학회지
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• 제13권3호
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• pp.93-98
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• 2011

To analyze and evaluate the performance of developing air to water multi heat pump, the heat pump was installed and tested at low energy house in Daejeon, korea. Heating capacity of heat pump is 16.5KW and cooling capacity is 14.0KW. Space heating/cooling, floor heating and hot water is available. The results performance evaluation of heat pump in lab test showed that the coefficient of performance (cop) was 3.75, and heating capacity was 16.0KW in ambient temperature $7^{\circ}C$. Also at ambient temperature $-15^{\circ}C$, the COP was 1.69. At a low energy house, floor heating is controled by a floor heating water temperature and a room temperature. The COP of heat pump is decreased with frequent on/off operation for controlling of floor heating water temperature.

• 대한기계학회논문집A
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• 제31권4호
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• pp.506-516
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• 2007

In this paper, a study on low-velocity impact response of four different sandwich panels for the hybrid bodyshell and floor structure application of the Korean low floor bus vehicle was done. Square samples of 100mm sides were subjected low-velocity impact loading using an instrumented testing machine at six energy levels. Impact parameters like maximum force, time to maximum force, deflection at maximum force and absorbed energy were evaluated and compared for four different types of sandwich panels. The impact damage size and depth of the permanent indentation were measured by 3-Dimensional Scanner. Failure modes were studied by sectioning the specimens and observed under optical microscope. The impact test results show that sandwich panel with composite laminate facesheet could not observe damage mode of a permanent visible indentation after impact and has a good impact damage resistance in comparison with sandwich panel with metal aluminum facesheet.

• 대한인간공학회지
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• 제30권5호
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• pp.659-669
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• 2011

Objective: The aim of this study is to suggest a package layout guideline for low-floor bus by interview with passengers and observations of their behavior. Background: Increasing attention has been introduced the low-floor bus to be more suitable for use by transportation handicapped. Complex issues are involved in providing comfortable services to all people. We are going to suggest package layout guidelines for more comfortable and suitable travel to all people. Method: The two times of survey and video observation sessions were conducted on low-floor buses in Seoul; (1) a finding of potential issues in the first session, (2) a confirming of issues from the last session. Results: The three of major issues were founded in this study; (1) difficulties in supporting body when standing, (2) difficulties in sitting on front wheel pan seat, (3) difficulties in passing through the aisle. Conclusion: There were clear differences between public and transportation handicapped in using some tools which are used for support body such as roof hand rails, side hand rails, and hand rail rings. Some of design problems were founded to improve from the perspective of ergonomics and universal design. Such differences and design guidelines have to be considered in bus design as well as commercial vehicle. Application: The proposed design guidelines can be used to development of low-floor bus and other public transportations.

• 한국자동차공학회논문집
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• 제15권6호
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• pp.50-61
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• 2007

The structural stiffness, strength and stability on the bodyshell and floor structures of the Korean Low Floor Bus composed of laminate, sandwich panels and metal reinforced frame were evaluated. The laminate composite panel and facesheet of sandwich panel were made of WR580/NF4000 glass fabric/epoxy laminate, while aluminum honeycomb or balsa was applied to the core materials of the sandwich panel. A finite element analysis was used to verify the basic design requirements of the bodyshell and the floor structure. The use of aluminum reinforced frame and honeycomb core was beneficial for weight saving and structural performance. The symmetry of the outer and inner facesheet thickness of sandwich panels did not affect the structural integrity. The structural strength of the panels was evaluated using Von-Mises criterion for metal structures and total laminate approach criterion for composite structures. All stress component of the bodyshell and floor structures were safely located below the failure stresses. The total laminate approach is recommended to predict the failure of hybrid sandwich composite structures at the stage of the basic design.