Numerical simulation and analysis of mechanized suppression process of seedbed with whole plastic film mulching on double ridges

In order to achieve the construction standard of high mechanized performance of the seedbed with whole plastic-film mulching on double ridges,in this study,the forms of suppression failure were analyzed,and the key factors influencing the suppression performance were determined based on the structure of the seedbed suppression device and its working principles.The discrete element method was adopted for numerical simulation on the suppression process of the seedbed with whole plastic film mulching on double ridges;the parameters during the interaction between the suppression device and seedbed soil were extracted and analyzed,such as contact area,sinkage and horizontal traction resistance trend of press wheels on big ridges and furrows of small ridge.Taking the suppression load on big ridges,suppression load on furrows of small ridge,and advancing velocity of the combined operation machine as the independent variables,qualified rate of suppression as the response value,a mathematical model between the test factors and qualified rate of suppression was established,to explore the influence sequence of the factors on suppression qualified rate.The optimal working parameters of the suppression device were finally obtained:the suppression load on big ridges was 40 N,suppression load on furrows of small ridge was 69.8 N and the machine advancing velocity was 0.98 m/s,and the achieved mean value of suppression qualified rate was 92.6%.Field verification test showed that the mean value of suppression qualified rate was 90.3%,a mere difference of 2.3%compared with the simulation result.The actual operation of the sample machine was basically consistent with the simulation process and could reveal the mechanized suppression operation mechanism of the seedbed with whole plastic film mulching on double ridges,indicating that the established DEM model and its parameter setting were relatively accurate and reasonable.

Mechanism analysis and performance improvement of mechanized ridge forming of whole plastic film mulched double ridges

In order to achieve high-performance and mechanization construction standard of whole plastic mulched double ridge seedbed,and to meet its forming process and corresponding agronomic requirements of the mechanized double ridge seedbed,the key working parameters such as the speed of rotary blade group,the thickness of upturned sod and the power consumption of rotary blade group under different parameters were analyzed based on related working performance in ridge forming.Also,the test factors and their range of values were finally determined in this study.Discrete element method(DEM)simulation was applied in the numerical simulation of the mechanized ridge forming process of whole plastic mulched double ridges,and the ridge forming effect and digging resistance variation characteristics of different types of shovels were compared.Taking the forward speed of the combined machine,the penetration angle of the arc-shaped shovel and the depth of rotary tillage as independent variables,and the qualified rate of seedbed tillage as the response value,the mathematical model between the test factors and the qualified rate of the seedbed tillage was established,to explore the influence sequence of the factors on the qualified rate of seedbed tillage,and obtained the following optimal working parameters of the ridge forming device:the advancing velocity of the combined machine of 0.50 m/s,penetration angle of the arc-shaped shovel of 31°,rotary tillage depth of 140 mm,and average qualified rate 95.20%of seedbed tillage in corresponding simulation verification test.Field test showed that the average qualified rate of seedbed tillage in ridge forming device was 93.60%,which was close to that of the simulation results.The actual working condition of the sample machine was basically in line with the simulation process and could relatively precisely reflect the mechanized ridge forming mechanism of whole plastic double ridges.The results showed that the established DEM model and its parameter setting were relatively accurate and reasonable.