Kunsan, South Korea
Kunsan, South Korea

Howon University is a university located in Gunsan, South Korea. Wikipedia.


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In this study, numerical analysis using the finite element was carried out for the behavior of steel plates and graphite/epoxy composite laminated plates by low-velocity impact. It verified the validity for the analysis result of the finite element program used in this study, the behavior of plate by weight and velocity changes was verified for each contact load. The composite laminated plate showed about two times more displacement difference than the steel plate by different impact loads. Therefore, it was investigated that the flexible characteristic of composite laminated plate had an effect on the impact absorption. © 2017 Elsevier Ltd


Park H.,Howon University
Key Engineering Materials | Year: 2015

Development of the Korean small scale aircraft(KC-100) has been carried out by KAI (Korea Aerospace Industry Ltd.) for the BASA(Bilateral Aviation Safety Agreement) program with FAA. The KC-100 aircraft adopted the environmental friendly whole composite structure concept due to low fuel consumption owing to its light weight. However the composite structure has a disadvantage. They are very weak against impact damage due to FOD (Foreign Object Damage). This study is to investigate the residual compressive strength of the carbon/epoxy fabric and UD (Unidirectional prepreg tape) laminate due to impact damages. This residual compressive strength test follows fully the ASTM standard test procedure. Experimental investigation results reveal the residual strengths and the damage mode and size of impact damage specimens. Through these tests, it is found that the residual strength of the impact damage specimens is greatly reduced in comparison to the undamaged specimens depending on increase of both the indentation depth and the impact energy. The size and shape of damage zone greatly affects the reduction of the compressive strength.


Park H.,Howon University
Key Engineering Materials | Year: 2016

In this study, structural design and analysis of the automobile bonnet is performed. The flax/vinyl ester composite material is applied for structural design. The Vacuum Assisted Resin Transfer Molding(VARTM) manufacturing method is adopted for manufacturing the flax fiber composite bonnet. A series of flax/vinyl ester composite panels are manufactured, and several kinds of specimens cut out from the panels are tested to obtain mechanical performance data. Based on this, preliminary structural design of the automobile bonnet is performed. Finally, this study is to investigate the residual compressive strength of the flax/vinyl ester laminate due to impact damages. Through investigation on compressive strength, design allowable of flax/vinyl ester laminate is determined by the experiment to address design criteria of the composite structure. © 2016 Trans Tech Publications, Switzerland.


Park H.,Howon University
Key Engineering Materials | Year: 2016

This study is to investigate the compressive strength of the carbon/epoxy thick laminate after damage. Through damage tolerance of thick laminate is not standardized test because specimens exceed typical specimen thickness described in the ASTM standard, design allowable of thick laminate shall be determined by the experiment to address design criteria of the structure and incorporate functional capability with damage level. In this study, it is performed the research on damage tolerance of thick laminate adopting aircraft structure. The damage tolerance of thick laminates such as no damage and impact damage is evaluated under compression loading. © (2016) Trans Tech Publications, Switzerland.


Kwon Y.-I.,Howon University
International Journal of Air-Conditioning and Refrigeration | Year: 2016

In the air distribution design of a small theater, either a downward or an upward displacement ventilation is applied generally. The cool air is supplied from openings distributed over the ceiling and extracted beneath the seats for the downward flow and supplied from beneath the seats and extracted from the ceiling for the upward flow system. By the change of air exchange rate (ACH) produced by two divergent ventilation systems inside theater, thermal comfort and ventilation effectiveness around the seats show a different phenomenon. Thereby, it can be seen that the selection of the ventilation system is a significant factor in energy saving. CFD calculations for this study were performed to investigate the effects of various parameters (ADPI and ACE) of air distribution system applied in order to save the cooling energy. This paper focuses mainly on the effect of the varied volume flow rate depending on the ventilation system. The ventilation performances of the downward displacement system are compared quantitatively with the upward displacement system using the concept of the LMA of fresh air. © 2016 World Scientific Publishing Company.


Park H.,Howon University
Key Engineering Materials | Year: 2014

Recently, the development need of environmental and fuel efficient aircrafts has been emphasized as an eco-friendly requirement in response to high oil prices. Accordingly, it is necessary to develop the next-generation eco-friendly and high fuel efficiency engine technology to enhance the fuel efficiency and aerodynamic performance of aircrafts for the purpose of reducing carbon dioxide emission amount prior to collecting and dealing with air pollution substances being discharged. In this study, development of the turboprop propeller blade for turboprop engine including aerodynamic and structural design and analysis was performed. The proposed propeller will be used as a candidate propeller for a regional aircraft which has been developed in Korea. Because the propeller for the target aircraft must endure the high bending and twisting moment loads during the flight operation, the high stiffness and strength carbon/epoxy composite material is used as a major structure materials. As a design procedure for the present study, firstly the structural design load is estimated through the aerodynamic load case analysis, and then flanges of spars from major bending loads and the skin from shear loads are initially sized using both the netting rule and the rule of mixture. In order to investigate the structure safety and stability, the structure analysis is carried out by finite element analysis using commercial code, MSC. NASTRAN. In addition, because the propeller should be safe against the bird strike, the bird strike phenomenon is analyzed using a commercial code, ANSYS. © (2014) Trans Tech Publications.


Park H.,Howon University
MATEC Web of Conferences | Year: 2016

In this work, a structural design and analysis on automobile bonnet using natural flax fiber composite is performed. Through the structural analyses using commercial FEM software, it is confirmed that the designed automobile bonnet using natural composite is acceptable for structural safety. And also, the damage is a critical problem in composites during their service in structural applications. Therefore, study on self-healing concept of bonnet structure was performed. © 2016 Owned by the authors, published by EDP Sciences.


Park H.,Howon University
MATEC Web of Conferences | Year: 2016

This paper performed aerodynamic, structural design and analysis of the horizontal axis blade of low noise 1kW class small wind turbine system that can be operated at homes and designed to display excellent performances in low wind velocity regions such as Korea. In terms of the material applied, glass/epoxy that is both economical and excellent in its performance was applied. Structural test was conducted to verify whether the actual movement of the blade designed is consistent with the theoretical analysis result. In addition, structural safety review was performed through the structural analysis of a tower for installing the wind turbine system developed. © 2016 Owned by the authors, published by EDP Sciences.


In developed countries, expansion of communication technology has resulted in continual increase in the construction of data centers with high-density cooling loads. Throughout a year, IT equipment installed in a data center generates large and constant cooling load. As a result, data centers may be consuming an ever-growing amount of energy. The cooling system utilizing the energy of outside air is applied universally to reduce data center energy consumption. The application of the cooling system to the outdoor air cooling system of a data center considers that temperature efficiency and ventilation performance vary depending on the type of ventilation system. The displacement and mixed ventilation method can be applied generally to a data center. The efficiency of a ventilation system depends on inside temperature or contaminant concentrations in room and outlets. This study thus aims to evaluate the ventilation performance that varies according to type of ventilation system installed in the data center. Ventilation efficiency is assessed by applying the concept of total air age and considers the fresh air ratio and age of return air. Further, temperature efficiency gained by utilizing temperature difference is used to assess causes for changes in ventilation performance. © 2016, The Korean Society of Mechanical Engineers and Springer-Verlag Berlin Heidelberg.


Park H.,Howon University
Composites Part B: Engineering | Year: 2016

In this study, aerodynamic and structural design of the propeller blade for an advanced turboprop aircraft is performed. Both the vortex theory and the blade element theory are used for aerodynamic design and analysis of the propeller. The propeller must endure various critical loads such as aerodynamic bending, torsion and shear, centrifugal force, vibration, etc. in various flight operations. Therefore the high stiffness and strength carbon/epoxy skin-spar-foam core sandwich type structure is adopted for improvement of lightness. In structural design, the structural design load is selected through investigation of fluid-structure interaction analyses. From investigation of both aerodynamic and structural design results, it is found that the proposed blade has a good aerodynamic performance as well as an allowable structural safety. © 2016 Elsevier Ltd. All rights reserved.

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