Dynamics Simulation And Experimental Investigation Of Earth Auger Bit-soil Based On EDEM

China has a vast territory and complex topography.The mountainous and hilly south of China is dominated by the forestry and fruit industry.Afforestation and fruit tree planting play an important role in driving the economic development in the south and promoting the construction of an environment friendly society in China.At present,the domestic forest and fruit industry afforestation planting,fruit tree transplantation mainly artificial,great labor intensity,low operational efficiency;The development lagged behind of portable pit digging machinery is the bottleneck problem that restricts the rapid development of China’s fruit and forestry industry.In this paper,the scientific study approach of integrating theory with practice is used to conduct an in-depth study on the technical problems of the mountain operation of portable pit digger.According to the working process and functional requirements of the pit digger,a portable pit digger bit was designed,and the dynamic simulation analysis of the bit-soil mod el was carried out based on discrete element method.The main research c ontents and results are as follows:1)according to the hilly area research results at home and abroad,found the portable digging machines in the actual operation process will be frequent "drill jump" phenomenon(The bit rebounds at the moment when the blade is in rigid contact with gravel and root cap),in order to overcome this problem,the cone-shaped spiral earth digging machine bit is designed,When the earth auger drilling opportunity comes to the rocks and roots in the soil,Change the instantaneous upward impact force to gradually to both sides of the torque force,the pit wall reaction force to prevent the earth auger drilling out of the tree pit,protect the operator and the safety of the machine.2)According to the pure cutting principle,a mathematical model of cutting blade resistance to soil entry is established and the optimal value range of cutting tool spiral Angle and angle of inclination edge is obtained by using Matlab programming to optimize the algorithm;The force analysis of earth auger drilling bit’s resistance is carried out and the data analysis provides data support for the design of cutting tools.3)soil model is established by discrete element simulation software EDEM,use three-dimension drawing software drawing earth auger bit model,through the study EDEM under different rotational speed and feed rate of earth auger torque dynamic mechanics parameters and its influencing factors(drill rotation speed,drill feed speed,soil environment)and the relationship between the structural parameters of working parts.Optimize and design the bit parameters to get the bit with good performance.4)Taking typical rocky mountain soil in hilly and mountainous areas as test samples,soil bin test was carried out to measure the rotary torque of earth auger drilling bit at different rotational speed and feed rate.The rotary torque of the earth auger drilling bit in the working process was collected by the dynamic torque sensor to verify the reliability of the relevant parameters of the optimized earth auger drilling bit.