玉米根土复合体剪切性能试验

Cutting Performance of Corn Root-soil Composite

以玉米品种沈农46自然状态的根土复合体为试验材料,在电子万能试验机和自制的试样周围压力系统上进行剪切力学性能试验。试验结果表明:含水率是影响极限剪切应力的最显著自然因素,极限剪切应力基本随着含水率增加而增大;距离根茎中心约20 mm的竖直剖面极限剪切应力最大,通过根茎中心的剖面次之,对于大于20 mm的其他剖面,距离根茎中心越远,极限剪切应力越小,结合垄作规格,破茬刀在距离垄台中心40 cm左右的剖面进行作业是合理的;在该剖面地表下20～60 mm位置,玉米须根最发达,抗剪切应力最大,约为5.20～7.15 MPa,是破茬装置功率损耗最大的工作段。

Taking natural root-soil composite of corn Shennong 46 as test material,cutting mechanical tests were carried out in the universal test machine and homemade pressure system around specimen.The results showed that moisture content was the key natural factor influencing ultimate shear stress,which increased with moisture content.The ultimate shear stress in vertical profile 20 mm away from root center was the largest,and the secondary was in vertical profile through root center.For vertical profiles more than 20 mm away from root center,the longer distance,the smaller ultimate shear stress.Combining with ridge-till specifications,reasonable cutting section for stubble-cutting disc was 40 cm away from ridge center.In the vertical section,the greatest shear stress existed at a depth of 20 ～ 60 mm from the surface of earth,was about 5.20 ～ 7.15 MPa.The maximum power was consumed in this depth range for rootstalk cutting mechanism.