玉米根茬剪切力学性能试验与分析

为提高免耕播种机破茬刀的工作性能,需要分析剪切速度、切刀刃型及剪切方式对根茬剪切性能的影响规律,采用微机控制电子万能试验机对玉米根茬进行上述三因素随机区组剪切性能试验。结果表明:剪切方式对最大剪切力的影响最大,其次是剪切速度;切刀刃型对最大剪切力的影响较小;最大剪切力随着剪切速度的增大而减小;同一刃型切刀在相同剪切速度下,横切时最大剪切力最大,劈切时最大剪切力最小;同一剪切方式在相同剪切速度下,直刃切刀的最大剪切力最大,凸圆刃切刀的最大剪切力最小;不同剪切方式,切茬过程的负荷-变形曲线不同。

Experiment and Analysis of Shear Mechanical Property of Corn Stubbles

In order to improve the performance of stubble-cutting disc on no-tillage planter, it is needed to analyze the effect of shear speed, the cutting edge type and the shear mode on shear properties of stubbles. Using computer controlled electronic universal test machine, shear properties of corn stubbles were experimentally studied for randomized combination of above-mentioned three factors. Results indicate that the shear mode has the largest effect on maximum shear force, next is shear speed, while the cutting edge type has smallest effect. The maximum shear force decreases with the increase of shear speed. At the same shear speed, for the same cutting edge type, the crosscut provides the largest maximum shear force, and the chopping provides the smallest one. At the same shear speed, for the same shear mode and, the straight edge has the largest maximum shear force, while the convex edge provides the smallest one. Load-deformation curve in stubble cutting process is dependent on shear mode.