小麦秸秆剪切力学性能的测试

为分析小麦茎秆在剪切过程中力的变化规律,以及不同加载速率对剪切强度和剪切功的影响,选择成熟期自然状态下风干的宜宾1号、矮抗58、周麦22和豫麦7号4个品种小麦茎秆的第2～4节间为研究对象,采用美国FTC公司生产的TMS-PRO型质构仪在茎秆节间中心进行横纹剪切试验,测定不同加载速率下不同品种不同节间的最大剪切力、剪切强度以及剪切功。结果表明:小麦茎秆在剪切过程中力的变化规律是先上升再减小,然后上升直至切断最后卸载的变化过程,4个品种小麦茎秆不同节间的硬度为37.3～191.0N,剪切强度为4.2～9.8MPa,剪切功为43.53～432.23mJ;同一小麦品种不同节间的剪切强度和剪切功均为第2节间最大,第3节间次之,第4节间最小。运用SPSS软件对不同加载速率对剪切强度和剪切功进行显著性检验,分析结果表明不同加载速率对剪切强度和剪切功均无显著影响。

Test of shear mechanical properties of wheat stalks

In order to analyze the variation of loading in the process of shear and whether different loading rates have an impact on shear strength and shear energy or not, four different species of wheat stalks in mature stage and dried under natural conditions were selected, which were Yibi No.1, Aikang 58, Zhoumai 22 and Yumai No.7, and the stems of their second, third and fourth internodes were chosen for study. The middle of each internode was tested for cross striations shear on the TMS PRO type Texure Analyzer produced by the U.S.FTC company. Through the shear testing, the biomechanical properties of the maximum loading, shear strength and shear energy were measured for various kinds of wheat stalks on different internodes with different speeding rates. The study result indicates that the variation of loading in the process of shear was that the loading increased at the beginning, then reduced because of its structural features, then added rapidly until to rupture. Meanwhile, the hardness, shear strength and shear energy on different internodes of the tested wheat stalks were respectively within the ranges of 37.3~191.0 N, 4.2~9.8 MPa,and 43.53~432.23 mJ. As for the shear strength and shear energy on different internodes of the same species of wheat stalks, those on the second internode is the largest, the fourth is the least. At last the significance test for shear strength and shear energy was run by applying SPSS, the result shows that different speeding rates have no significant impact on shear strength and shear power.