油菜茎秆径向压缩特性试验研究  

An Experimental Study of the Radial Compression Characteristics of Rape Stalks

作　　者：魏俊逸 宗望远[1,2] 詹广超 WEI Junyi;ZONG Wangyuan;ZHAN Guangchao(College of Engineering,Huazhong Agricultural University,Wuhan 430070,China;Key Laboratory of Agriculture Equipment in Mid-lower Yangtze river,Ministry of Agriculture and Rural Affairs,Wuhan 430070,China)

机构地区：[1]华中农业大学工学院,湖北武汉430070 [2]农业农村部长江中下游农业装备重点实验室,湖北武汉430070

出　　处：《江西农业大学学报》2021年第1期198-205,共8页Acta Agriculturae Universitatis Jiangxiensis

基　　金：国家自然科学基金项目(31671592)。

摘　　要：【目的】为了研究油菜茎秆在脱粒过程中的破碎机理,寻找减少油菜脱粒过程中茎秆破碎的控制策略。【方法】利用微机控制万能材料试验机对油菜茎秆进行径向全压缩和局部压缩试验。对油菜茎秆的径向弹性系数和力学特性进行了测量,对不同曲率半径压头对油菜茎秆局部压缩力学特性的影响进行了研究。【结果】试验结果表明,油菜茎秆径向压缩屈服之前有一个线弹性阶段,茎秆受力与形变表现出良好的线性关系,油菜茎秆径向截面弹性系数为kτ=(1.14±0.16)N/mm;油菜茎秆局部压缩试验中油菜中部主茎秆的屈服极限平均值为150.55 N;通过对油菜茎秆全压缩试验和局部压缩试验对比发现,全压缩试验中油菜茎秆直接被压溃,无明显屈服阶段,茎秆的破碎主要是由于所受载荷超过了茎秆纤维层之间的约束力,其裂痕方向与茎秆轴向平行;油菜茎秆局部压缩试验中,不同曲率半径的压头对茎秆径向压缩受力影响显著,茎秆在相同形变下,曲率半径越大,茎秆受力越大。【结论】建立了油菜茎秆径向压缩理论计算模型,对油菜茎秆所受径向压力的实测值与理论模型计算值对比,发现理论值与实际值的增长趋势一致,验证了该茎秆受力计算模型的可行性。[Objective]To study the breaking mechanism of rape stalks in the process of threshing and pro⁃pose control strategies to reduce it.[Method]A microcomputer-controlled universal material testing machine was used to apply compression loads on the stalks.The loads were applied in two ways:along the full length of the stalk and on part of the stalk.The radial elastic coefficients of rape stalks were measured,and the effects of different indenter curvature radii on the mechanical properties of partially compressed rape stalks were studied.[Result]The experimental results showed that there was a linear elastic stage before the radial compression yield of the rape stalk,and the stress and deformation of the stalk showed a good linear relationship,and the elastic coefficient of the radial section of the rape stalk was kτ=1.14±0.16(N/mm).In the local compression tests of rape stalk,the average yield limit of the main stalk in the middle of the rape plant was 150.55 N.Through the comparison of the full compression tests and partial compression tests of the rape stalks,it was found that the rape stalks were directly crushed in the full compression tests,and there was no obvious yield stage,and the stalk was mainly broken because the load exceeded the binding force between the fiber layers of the stalk,the crack direction was parallel to the axial direction of the stalk.In the partial compression tests,the indenter with different curvature radii had a significant effect on the radial compression force of the stalk.Under the same deformation of the stalk,the larger the curvature radius was,the greater the stress on the stalk was.[Conclusion]The theoretical calculation model of rape stalk radial compression was established.Comparing the measured values of radial pressures on rape stems with the calculated values of the theoretical model,it was found that the growth trend of theoretical values was consistent with the actual values,which verified the feasi⁃bility of the calculation model.

关 键 词：油菜茎秆 压缩 弹性系数 受力模型 

分 类 号：S225.99[农业科学—农业机械化工程]