Simulation And Experimental Study On Cutting Process Of Silage Corn Harvesting Header

Silage corn is a green crop with high yield.It can be converted into green feed for poultry and livestock after being harvested,chopped and fermented.Compared with common corn,silage corn has higher nutritional value,higher yield per unit area and better fiber quality.With the increasing demand for high-quality green fodder in animal husbandry,the planting area of silage corn has increased rapidly under the promotion of the "grain to feed" pilot work of the Ministry of agriculture and rural areas.The harvesting time of silage corn is from the end of milky stage to the pre waxing stage.The best harvesting time is short.In order to achieve timely harvesting,it is necessary to ensure high harvesting efficiency,which also determines the necessity of mechanized harvesting of silage corn.One of the key technologies of silage harvester is header technology.Because of different planting techniques,there are some differences between domestic and foreign silage headers.The foreign silage header is a large width form,which is not suitable for domestic silage harvesting.Domestic research on header mainly focuses on feeding technology,transmission system and key cutting technology of header,but less on cutter technology.Therefore,this paper focuses on the cutter technology of silage machine,which provides a theoretical basis for the subsequent research on silage harvester technology.Based on the above,this paper mainly carried out the following research work:(1)In order to analyze the process of cutting corn straw with a disc cutter better,the mechanical properties of silage corn straw with 81.7% moisture content were studied in this paper.Through the shear test and tensile test of straw skin,the shear strength was 42 MPa,the tensile strength along the grain was 140 MPa,and the elastic modulus was 933 MPa.The static friction coefficient is 0.327 and the dynamic friction coefficient is 0.301.(2)In this paper,the operation theory of the disc cutter of the silage header is analyzed,and its motion equation,velocity equation and cutting distance equation were determined.Based on the analysis of the static and dynamic sliding cutting angle of the saw tooth,the changing law of the sliding cutting angle with the change of the working position of the saw tooth was obtained.This paper analyzed the force of the disc cutter in sawing operation,and determined the main force and reason.(3)In order to reduce the influence of the uncertain factors in the field harvest,and to accurately explore the cutting force,cutting power consumption and other parameters of the disc cutter when harvesting silage corn,a disc cutter test-bed for silage corn harvester was designed.The single factor test-bed tests were carried out for the forward speed of the header,the rotation speed of the disc cutter,the inclination angle of the disc cutter and the diameter of the straw,and the influence rule of the above factors on the cutting force was obtained.(4)With the help of computer simulation technology,the cutting model of cutting straw with disc cutter was established.The single factor simulation tests were carried out for four factors,namely the forward speed of header,the rotating speed of disc cutter,the inclination angle of disc cutter and the diameter of straw.The peak value of cutting force was selected as the test index,and the influence rules of each factor on cutting force in the simulation test were obtained.The accuracy of the established cutting model was verified by comparing the simulation single factor test results with the test-bed single factor test results.By using the validated cutting model,the single factor simulation tests were carried out on the factors of the saw tooth edge angle of the disc cutter,the shape of the cutting edge of the cutter,the skewness of the corn stalk,and the law of its influence on the cutting force was obtained.(5)In order to explore the interaction between the working parameters of the header on the harvest performance and determine the best working parameters of the header,four factors and five horizontal center combination tests were carried out with the help of the disc cutter test-bed,including the forward speed,the rotating speed of the disc cutter,the horizontal inclination of the disc cutter and the straw diameter.Regression equation fitting was carried out for the test results,and the significance of variance analysis was tested.Finally,the response surface was set up The optimum working conditions of silage corn header were obtained,that is,silage corn: the horizontal inclination of cutterhead is 9.77 °,the forward speed is 3.27 km/h,the rotating speed of cutterhead is 270.24 rpm,and the diameter of straw is 25.59 mm;yellow corn: the horizontal inclination of cutterhead is 8°,the forward speed is 3.00 km/h,the rotating speed of cutterhead is 240 rpm,and the diameter of straw is 24.00 mm.