Analysis And Standardization Of Structural Parameters Of Solar Greenhouse In Guanzhong Area

The technical level and comprehensive management level of facility agriculture are important factors determining agricultural modernization.As a large agricultural country,facility agriculture in China has made great progress in recent years.However,due to the late start of facility agriculture in China,there is still a big gap compared with some agricultural developed countries.As an important part of facility agriculture,solar greenhouse has played a great role in solving the major livelihood problem of people’s "vegetable basket",and has also brought considerable economic benefits to producers.Although China has successively issued a series of recommended documents on the construction standards,norms and regulations of solar greenhouse in recent years,farmers around the country still focus on experience in the construction of greenhouse,which has nothing to do with the provisions of the norms.As a result,these recommended norms have not been well implemented,resulting in uneven greenhouse construction parameters,and the problem of nonstandard greenhouse structure design standards has gradually become prominent.The main research object of this paper is the skeleton structure of solar greenhouse,among which the circular pipe truss structure without column and elliptical pipe single pipe structure are the most common in Guanzhong area.Through the research,we can finally achieve the standardized design of greenhouse structure under the condition of meeting the requirements of the most basic load code.The main conclusions of this paper are as follows:(1)In order to determine the basic building parameters suitable for solar greenhouse in Guanzhong area,the spatial structure layout of local greenhouse was investigated on the spot,and the building parameters of solar greenhouse in Guanzhong area were calculated,compared and summarized by using the basic principles of mathematics and geography.The results show that the front roof angle of the greenhouse is 28.36 °,the azimuth angle is 5 ° south by west,the front roof curve is cubic spline curve,and the rear roof elevation angle of 36 ° is the optimal building parameter.At the same time,in order to facilitate the calculation of the basic building parameters of the solar greenhouse,a parameter solver is developed based on the secondary development of MATLAB.The basic building parameters of the solar greenhouse can be obtained only by inputting the local latitude,solar declination angle and time angle,which is conducive to the calculation of the basic parameters of the solar greenhouse in different regions and improves the work efficiency.(2)After determining the optimal greenhouse building parameters,taking a structure and a member combination form in the greenhouse as an example,three different load combination conditions are applied to the structure by using Midas Gen finite element analysis software,and the most unfavorable load combination is determined by comparing the displacement and stress nephogram of the structure.Based on the national code,the stability and bearing capacity of the overall structure under the most unfavorable load combination are comprehensively analyzed.(3)The mathematical optimization model is established,the parameter approximation method is adopted,and then the transverse spacing of each skeleton of solar greenhouse under different structures and different rod combinations is adjusted and optimized based on MIDAS Gen finite element analysis software,and the maximum spacing and optimal rod combination form of each skeleton are calculated.The standardized structure system of solar greenhouse in Guanzhong area is designed,which not only provides convenience for greenhouse builders,but also provides a new idea for the modular development of solar greenhouse in other areas.