Research On FEM-Based Working Mechanism Of Transverse Knife On Helical Rotary Roller

Further research of soil cutting problem, in which some methods, such as the static of rigid body method, the dimension analytic method and the plastic limit balance method, were used to forecasting the cutting resistance and made certain progress, is one of important subjects in the recent three decades. However, due to the respective existent limitation and insufficiency of the methods, researchers were unable to obtain the complete quantitative analysis result. In recent years, the rapid development of computer technology as well as the development and utilization of finite element software, have made new progress to the research of soil cutting problem.This thesis based on the finite element simulation technology, mainly studied soil-cutting process of specific sticky soil. And tests were carried out to validate the result of dynamic numerical simulation. The main content includes:(1) Finite element analysis model of soil-cutting problem with transverse knife on helical rotary bury-stalk roller, after analyzing the characteristics of the cutting process, was established with elastic-plastic theory. Moreover, Lagrange incremental method was used to deal with the geometric non-linear problem of the soil-cutting process, and revised non-linear elastic-plastic Drucker-Prager model was utilized to simulate the soil-cutting process and get some parameters, such as stress distribution, cutting resistance and shear angle between soil and transverse knife.(2) The analysis results showed, when narrow transverse knife went completely into the soil, increased cutting speed and angle could make larger cutting resistance, between which the relationship were non-linear, while soil-cutting depth had little effect on the cutting resistance, and there was a linear relationship between cutting traction resistance and soil-cutting width.(3) Changes about equivalent stress and the three directions mechanical properties of the helical transverse knife were indicated in the three-dimensional simulation of soil-cutting process, provide the basis for optimal structural parameters of the helical transverse knife.(4) If the cutting speed was lower than 1m/s, the cutting angle, compared with cutting speed, had larger effect on the cutting resistance, as well as the soil-cutting depth had no obvious influence on the cutting resistance.(5) It was found that, by comparing the simulation and test, the result of shear angle was similar and the error between simulation resistance and test resistance was around 11%, as the analysis model was established under a certain assumption conditions. Therefore, the simulation results of cutting resistance are trustworthy, and it may provide support to further finite element method based research of soil dynamics problem.