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This study was carried out to develop rain shelter which can make an appropriate size and environment for Chinese cabbage rainproof cultivation. Fifty three farms with chinese cabbage rainproof cultivation system have been investigated to set up width and height of rain shelter. Mostly the width of 6m was desired for rain shelter and the height of 1.6m for their eaves, so these values were chosen as the dimensions for rain shelter. After an analysis of their structural safety and installation costs by the specifications of the rafter pipe, Ø25.4×1.5t and 90cm have been set as the size of rafter that such size costs the least. This size is stable with 27m·s−1 of wind velocity and 17cm of snow depth. Therefore it is difficult to apply this dimension to area with higher climate load. In order to sort out such problem, the rain shelter has been designed to avoid damage on frame by opening plastic film to the ridge. Once greenhouse band is loosen by turning the manual switch at the both sides of rain shelter and open button of controller is pushed then switch motor rises up along the guide pipe and plastic film is opened to the ridge. Chinese cabbage can be damaged by insects if rain shelter is opened completely as revealed a field. To prevent this, farmers can install an insectproof net. Further, the greenhouse can be damaged by typhoon while growing Chinese cabbage therefore the effect of an insect-proof net on structural safety has been analyzed. And then structural safety has been analyzed through using flow-structure interaction method at the wind condition of 40m·s−1. And it assumed that wind applied perpendicular to side of the rain shelter which was covered by insect-proof net. The results indicated thatplastic film was directly affected by wind therefore high pressure occurred on the surface. But wind load on insect-proof net was smaller than on plastic film and pressure distribution was also uniform. The results of structural analysis by applying pressure data extracted from flow analysis indicated that the maximum stress occurred at the end of pipe which is the ground part and the value has been 54.6MPa. The allowable stress of pipe in the standard of structural safety must be 215MPa or more therefore structural safety of this rain shelter is satisfied.
본 연구에서는 배추 재배에 적합한 규격과 생육 환경을 조성해 줄 수 있는 비가림하우스를 개발하고자 하였다. 전국 53개 배추 비가림재배 농가를 대상으로 비가림하우스 구조실태 및 구조개선 희망사항을 조사하여 비가림하우스 폭과 높이를 설정하였다. 비가림하우스 규격은 농기계 작업의 용이성, 농가의 의견 등을 고려하여 폭6m, 처마높이 1.6m, 지붕높이 3.2m로 결정하였다. 서까래 규격별 구조안전성과 설치비를 분석한 후 설치비가 가장 적게 드는 Ø25.4×1.5t 파이프를 서까래로 하고 그 간격이 90cm인 모델을 기본 규격으로 결정하였다. 이 규격은 풍속 27m·s−1, 적설 17cm에 안전하기 때문에 이보다 기상하중이 큰 지역에는 적용하기가 곤란한데, 이를 해소하기 위해 피복재를 용마루까지 열어 골조 피해를 예방할 수 있는 구조로 설계하였다. 비가림하우스 양 측면에 있는 수동개폐기를 돌려 하우스밴드를 느슨하게 풀어주고 제어반에서 열림버튼을 누르면 개폐모터가 가이드 파이프를 따라 올라가면서 피복재가 용마루까지 개방된다. 피복재를 완전 개방할 경우 해충으로 인한 피해가 우려되므로 농가에서는 이를 막기 위해 방충망을 설치할수 있다. 배추를 재배하는 기간에 태풍이 지나갈 수 있기때문에 방충망이 구조안전에 미치는 영향을 분석하였다. 40m·s−1의 바람이 방충망으로 덮여있는 비가림하우스 측면에 수직으로 작용하는 조건에 대해 유동-구조 연성해석기법을 이용하여 구조안전성을 분석하였다. 유동해석 결과, 피복재 부분은 바람의 영향을 그대로 받기 때문에 피복재 표면에 압력이 크게 작용하였다. 방충망 부분에도 풍하중이 작용하였으나 피복재 부분보다는 압력이 작게 작용하고 분포가 균일하였다. 유동해석에서 도출된 압력데이터를 적용하여 구조해석한 결과, 최대응력은 파이프의 끝단 즉, 지면부분에서 나타났으며, 그 값은 54.6Mpa이었다. 구조안전 판단 기준인 파이프의 허용응력 215MPa 이내여서 구조적으로 안전한 것으로 판단되었다.
- Baek, C.H. 2008. Development of greenhouse models against weather disaster for oriental melon cultivation in Seong-ju region. Ph.D Thesis, Kyungpook Nat'l Univ.: p. 35-58 (in Korean).
- Japan Greenhouse Horticulture Association. 2005. Handbook of protected horticulture. 5th ed. Horticulture Information Center, Tokyo, Japan. p. 38-50 (in Japanese).
- Kim, M.K. and S.W. Nam. 1995. Experimental studies on the structural safety of pipe-house. J. Bio-Env. 4(1):17-24 (in Korean).
- Korea Agro-Fisheries & Food Trade Corp. homepage(http://www.kamis.co.kr). 2014.
- Lee, S.G. 1995. Structural design of plastic greenhouses for prevention of meteorological disaster. Kyungpook National University: p. 1-33 (in Korean).
- Lee, S.G., et al. 1995. Greenhouse construction standards. Agriculture and Fisheries Development Corporation. p. 20-60 (in Korean).
- Lee, S.G., H.W. Lee, J.W. Lee, and C.S. Gwak. 2006. A study method for structural safety improvement of greenhouse by structural analysis, Proceedings of the 2006 Annual Conference. KSAE:21 (in Korean).
- Lee, S.G., J.W. Lee, and H.W. Lee. 2004. Analysis of wind speed and snow depth of single-span plastic greenhouse by growing crop, Proceedings of the 2004 Annual Conference. KSAE:40 (in Korean).
- Ministry for Agriculture, Food and Rural Affairs(MAFRA). 2014. The status of the greenhouse and production records for vegetable crops in 2013. p. 11 (in Korean).
- Park, C.W., S.G. Lee, J.W. Lee, and H.W. Lee. 2005. Optimum design of greenhouse structures using continuous and discrete optimum algorithms. Proceedings of the 2005 Annual Conference. KSAE:33 (in Korean).
- Yu, I.H., E.H. Lee, M.W. Cho, H.R. Ryu, and D.G. Moon. 2013. Development of single-span plastic greenhouses for hot pepper rainproof cultivation. Protected Horticulture and Plant Factory. 22(4):371-377 (in Korean).10.12791/KSBEC.2013.22.4.371
- Yu, I.H., E.H. Lee, M.W. Cho, H.R. Ryu, and Y.C. Kim. 2012. Development of multi-span plastic greenhouse for tomato cultivation. J. Bio-Env. Con. 21(4):428-436 (in Korean).10.12791/KSBEC.2012.21.4.428
- Yu, I.H., H.J. Jeong, M.W. Cho, H.R. Ryu, and D.H. Goo. 2009a. Design of singlespan plastic greenhouse for straw-berry bench-cultivation. Proceedings of Korean Society for Bio-Env. Con., 2009 Autumn Conference 18(2):280 (in Korean).
- Yu, I.H., H.Y. You, Y.C. Um, M.W. Cho, and J.K. Kwon. 2009b. Structural design of plastic greenhouse for paprika cultivation. Proceedings of Korean Society for Bio-Environment Control, 2009 Spring Conference 18(1):196-200 (in Korean).
- Yum, S.H., K.J. Kwon, S.H. Sung, and Y.D. Choi. 2007a. The installation effect and optimal pipe sizes of an anti-wind net by computational analysis. J. Biosystems Eng. 32(6):430-439 (in Korean).10.5307/JBE.2007.32.6.430
- Yum, S.H., N.K. Yun, K.W. Kim, S.H. Lee, Y.H. Cho, S.J. Park, and M.K. Park. 2007b. The optimum specification of pipes in rain-sheltering greenhouse with roof vents for largegrain grapevine cultivation. J. Bio-Env. Con. 16(4):275-283 (in Korean).
- Yun, N.K., S.H. Lee, K.W. Kim, S.H. Yum, and I.B. Lee. 2007. Analysis on natural ventilation of single span greenhouse with insect screen. Proceedings of Korean Society for Bio-Environment Control, 2007 Spring Conference 16(1):123-126 (in Korean).
- Publisher :The Korean Society for Bio-Environment Control
- Publisher(Ko) :(사)한국생물환경조절학회
- Journal Title :Protected Horticulture and Plant Factory
- Journal Title(Ko) :시설원예ㆍ식물공장
- Volume : 23
- No :4
- Pages :293-302
- DOI :https://doi.org/10.12791/KSBEC.2014.23.4.293
Journal of Bio-Environment Control
