Simulation And Parameter Optimization Of Stubble Cutter Operation Process Based On Explicit Dynamics

Crop stubble returning is the most direct way of comprehensive utilization of stubble.The quality of maize stubble returning have a direct and strong impact on the seeding of next season,while the stubble roller is the key factor that directly affects the quality of maize stubble returning.The cutting efficiency of the existing stubble stubble roller is poor.This paper designed a double shaft stubble cleaner which can significantly improve the stubble breaking rate.By optimization of the blade structure parameters,to realize drag reduction and weight reduction.The structure size,cutters quantity and arrangement of the key components are determined by theoretical analysis.Its function are as follows:Firstly,rotating a stubble roller near ground with high rotation speed,cutting stubble and soil that is called first cutting.Secondly,the stubble from first cutting was sent to second cutter which is on the upper rear of the first cutter,the incompletely crushed stubble from the first cutter will be further crushed.Lastly,the stubble was spread evenly to the field,then the roller completely compress and smooth soil.This kind of machine with two times cutting can improve cutting efficiency and breaking rate,then can thoroughly utilize the fertilizer of soil.Stubble cutter work as an important executive component,its structure parameters and weight will seriously affect the power consumption.At present,most researchers optimize the structure of stubble cutter by static analysis,while the process of stubble cutter interact with soil and stubble is a dynamic process,so there is a big error between simulation and the fact.In order to simulate the operation process of stubble cleaner more really and effectively,using the explicit dynamics module of ANSYS,which is called LS-DYNA,to study the the interaction among stubble cutter,soil and stubble.By the analysis of the mechanical characteristics of the machine operation process,the feasibility of the design is verified.Set three structural parameters of the L type straight blade,bending angle,blade thickness and blade edge angle as the factors,set the mass of blade,the average cutting force as the goal,to build three factors quadratic function regressive mathematical model,analyze the influence of various structural parameters on the average cutting force and blade mass.The results shows that the importance order of factors that influence the average cutting is bent angle,blade thickness,blade edge angle.The influencing order for tool mass is bending edge angle,bent angle,blade thickness.Using multi-objective parameters optimization module in Design-Expert software,according to the mathematical model of the objective function,combing with boundary conditions of the test factors to solve this problem,it is found that bending angle is 117.3 degrees,the blade thickness is 0.56 mm,blade edge angle is10 degrees are the optimal structure for the blade.In order to verify the accuracy of the optimization of blade parameters and check the braking rate of the machine,the field test was hold.The results shows that the double shafts stubble cleaner has a higher stubble breaking rate in contrast to ordinary single shaft stubble cleaner,the optimized blade has drag reduction and weight reduction effect.All these studies can provide reference for the structural design and blade optimization.