Analysis of the Structural Safety in a Non-heating Greenhouse with a Single Cover for Citrus Cultivation in Jeju

This study was carried out to evaluate the structural stability in a non-heating greenhouse with a single cover for Citrus cultivation which was built up in Jeju on the basis of the drawing designed by Jejudo Agricultural Research & Extension Services and also to make use of the data for developing a standardized non-heating greenhouse in Jeju. The analysis of a structural stability was conducted by using CFX-5.7 and ANSYS under the design condition of a maximum accumulated snow-depth of 19.1 cm as well as an instantaneous maximum wind velocity of $36.6\;m{\cdot}s^{-1}$ which was set up on the basis of meteorological statistics in Jeju. As a result, the maximum von-Mises stress applied on pipes under the wind velocity of $36.6\;m{\cdot}s^{-1}$ showed a value of $250\;N{\cdot}mm^{-2}$ which was greater than the allowable stress of the pipe with a value of $235.4\;N{\cdot}mm^{-2}$ (=$2,400\;kg{\cdot}cm^{-2}$) and also $53.8\;N{\cdot}mm^{-2}$ under the snow-depth of 19.1 cm, respectively. This result suggested that the greenhouse be unstable under the design condition of an instantaneous wind velocity of $36.6\;m{\cdot}s^{-1}$ so that it was necessary for the greenhouse to be reinforced to secure the structural stability.

제주지역 감귤재배용 단일피복 무가온하우스의 구조안전성 분석

길이 40m,폭 5.5m의 단일피복 구조의 8연동 무가온하우스 상단부에 설계적설심 19.1 cm의 눈이 쌓인다는 조건과 시설 측면으로 설계풍속 $36.6\;m{\cdot}s^{-1}$의 바람이 분다는 조건 그리고 참고자료로 활용하기 위해 적용한 최대적설심 37.8cm의 눈이 쌓인다는 조건과 순간최대풍속 $60.0\;m{\cdot}s^{-1}$의 강풍이 분다는 조건에서 유동 및 구조강도 해석을 수행하였다. 적설하중 조건에서는 설계적설심 19.1 cm와 최대적설심 37.8cm에서 파이프에 걸리는 최대응력이 각각 $53.8\;N{\cdot}mm^{-2}$과 $107\;N{\cdot}mm^{-2}$으로 재료의 허용응력 보다 작은 것으로 나타나 안전한 것으로 분석되었으나, 설계풍속 $36.6\;m{\cdot}s^{-1}$와 순간최대풍속 $60.0\;m{\cdot}s^{-1}$의 풍하중 조건에서는 파이프에 걸리는 최대응력이 각각 $250\;N{\cdot}mm^{-2}$과 $672\;N{\cdot}mm^{-2}$으로 재료의 허용응력을 모두 초과하여 플라스틱하우스가 불안전한 것으로 분석되었다.