土壤-耕具接触的有限元仿真分析

Simulation of soil-tillage tool interaction using finite element analysis

利用数值模拟结合正交试验设计方法,研究不同刀具楔角、耕作深度和土壤-耕具间摩擦因数对切削阻力的影响,及切削过程中土壤裂纹的扩展形态。模拟结果表明:当楔角一定时,随着耕深和摩擦因数的增加,裂纹长度随之增加且趋于平缓;当楔角和耕深不变,摩擦因数不同时,裂纹形态的扩展趋势不同;当楔角为20°,耕深为10cm,摩擦因数为0.45时切削力较小;而当楔角为25°,耕深为20cm,摩擦因数为0.70时切削阻力较大。楔角、耕深及土壤-耕具间摩擦因数都是影响耕作过程切削阻力大小的因素,而且因素间的交互影响不可忽视。不同因素水平下土壤切削过程产生的裂纹形态及切削力大小不同。

Cutting resistance is one of the major energy consumption factors in plough.By numerical simulation and orthogonal design,this paper studies the cutting resistance affected by different rake angle,plowing depth and the coefficient of friction between soil and farming tools.This paper also investigates the extended forms of soil cracks in soil cutting process.Simulation results show：When the rake angle was fixed,the crack length increased and flattens with the increase of the tillage depth and friction coefficient;when the coefficient friction changes,the forms of soil cracks vary with the fixed rake angle and tillage depth.The cutting resistance is smallest with the rake angle of 20°,tillage depth 10cm,and the friction coefficient of 0.45;while the cutting resistance is largest with the rake angle of 25°,tillage depth 20 cm,and the friction coefficient of 0.70.In conclusion,the rake angle,tillage depth,and the coefficient friction between soil and tools are major factors for the cutting resistance in soil cultivation and the interaction among these factors should not be ignored.The forms of soil cracks and the cutting resistance force are different in different factors and levels.