Mechanical Properties Analysis And Optimal Design About The Structure Of Lateral-Move Sprinkler

At present,the development of sprinkler machines at domestic and foreign is mainly focused on large-scale central pivot sprinklers and translating sprinklers,both of which have the advantages of good water-saving effect,high degree of automation,and uniform irrigation effects,but the hundreds of meters determines that most of them worked at large-scale farms.In the northwestern region of China,the small-farm economy is still the dominant business model.Large-scale sprinklers are difficult to work in farmland less than 50 m in width.Therefore,light and small sprinklers that suitable for small farm's irrigation are urgently needed.The truss structure as the main support system of the sprinkler provides the necessary guarantee for the smooth operation of the sprinkler.Based on the large-scale sprinkler truss structure type,and combined with the actual demand for irrigation in northwestern areas,this paper designs a truss structure for a light and small-sized translational sprinkler to fulfil its economical requirements and the structural stability.The main research contents and research results are as follows:(1)In order to find out the rationality and deficiencies of the existing large-scale sprinkler truss structure construction,it is necessary to make a performance analysis of the force conditions of each pole.According to the survey of the mainstream irrigation machines in the market,two representative models were selected: the Volment Center pivot sprinkler and the vodar translation sprinkler.This chapter takes the single span structure of two sprinkler as the basic model,uses finite element ANSYS software to compare and analyze the displacement of each node and the stress of each member under different working conditions.With Davenport's spectrum,the influence of fluctuating wind loads was briefly discussed.The results show that the stability of the Volment sprinkler is better than the Vodar sprinkler.The truss structure(archbeam-stretch type steel)of the sprinkler has its rationality in structure,and the wind load has a great influence on the lateral stability of the structure.(2)According to the structure type of the truss structure of the Volment Center pivot sprinkler,combined with the actual land area in the northwest in china,a light and small translational sprinkler truss structure was preliminarily constructed.On this basis,the influence of the structural parameters(vector height ratio,height-to-span ratio and number of struts)on the structural performance of the complete machine was studied,and a reasonable truss structural dimension was finally determined.The results show that: considering the stability and economic efficiency of the truss,the height-to-height ratio of the model is recommended to be between 0.3~0.35,and the high-to-high ratio is recommended to be between 0.04~0.045.The number of struts is recommended to choose 5 groups(25 angle steel)is appropriate.(3)Based on the preliminary determination of the light and small sprinkler truss structure type,using the zero-order algorithm in the ANSYS software optimization module,the crosssectional dimensions of the sprinkler truss structure are determined by determining the design variables,state variables,objective function and optimization solution process.By optimizing the design,the truss structure of the light and small translating sprinkler that satisfied both stability and economy is finally obtained.The results show that the optimization effect of the truss structure size is obvious,and the light and small translational sprinkler truss structure can satisfy the requirements of lightness,stability and economy.