几种不同触土曲面耕作部件的力学性能仿真研究

Simulation Research on Mechanical Performances of Several Kinds of Cultivating Components with Different Soil-engaging Surfaces

优化耕作部件触土曲面形状,降低工作阻力,提高工作效率,始终是人们关注的问题。引入纵深比的概念,采用有限元法分析直线、抛物线、摆线、圆弧、仿生曲线(包含小家鼠、田鼠、蝼蛄、公鸡等爪趾触土面轮廓线)等分别作为触土曲面准线时,各种不同触土曲面耕作部件耕作力学性能的优劣。研究结果表明,耕作部件触土曲面准线和纵深比是影响工作阻力的两个重要因素。在小纵深比(0<L/B<1.0)的情况下,弯曲型耕作部件与直线型耕作部件相比普遍具有较优的耕作力学性能。仿生优化设计有可能获得性能优异的耕作部件,但仿生曲线情况复杂,设计过程中需特殊曲线特殊对待。抛物线式耕作部件在较宽纵深比范围内(0<L/B<1.5)都有可能获得较优的耕作力学特性。圆弧面耕作部件减阻性能略差。摆线适宜于设计具有较大纵深比(L/B≈1.2)的耕作部件触土曲面。研究对于土壤耕作部件的触土曲面减阻设计具有较重要的参考价值。

How to optimize the geometric shape of cultivating components to reduce the working resistance, thus enhancing working efficiency, is always paid much attention by humans beings. The mechanical properties and their discrepancies in different kinds of cultivating components with different soil-engaging surface directrix, after introducing the concept of longitudinal/depth （L/B） ratio, are analyzed and compared with finite element method. The directrix for each cultivating component’s soil-engaging surface is respectively composed of straight line, parabola, cycloid, circular arc and bionic curves including the soil-engaging surface contour line of the claw toes of house mouse, field mouse, mole cricket and cock. Results indicate that the soil-engaging surface directrix and longitudinal/depth ratio are two important factors to affect the working resistance. The curved cultivating components generally possess superior cultivating performance against the straight-line cultivating components with small L/B values （0L/B1.0）. Optimal mechanical performance of the curved cultivating components can be obtained by way of bionic optimization. However, the bionic curves used in the design of soil-engaging surface should be researched respectively for their complexity. A parabolic cultivating component, even in a broader range of longitudinal/depth ratio （0L/B1.5）, is possible to obtain good mechanical properties of cultivation. A cultivating component of circular soil-engaging surface is slightly poor in resistance reduction. A cycloid is suitable to the design of cultivating component’s soil-engaging surface with a bit big L/B value （L/B≈1.2）. The results of this research would have important reference values in the optimization design of cultivating component’s soil-engaging surface for reducing resistance.