不同收获期玉米秸秆剪切力学性能的研究简

目的]研究玉米秸秆的物理力学性能，可为研制低能耗、高效率的秸秆收获及加工设备提供不可或缺的基本技术参数，减少成本、缩短研发周期。方法]利用万能试验机，测试了不同收获期玉米秸秆的剪切力性能，并分析刀具的刃角、剪切速度、取样位置等因素对剪切力的影响。结果]各因素对试验指标（最大剪切力）的影响按大小次序是取样位置→收获期→刀刃角→剪切速度。刀刃角越小，剪切力越小，越省力；剪切力随着剪切速度的提高呈下降趋势；根部秸秆剪切力稍微大于中部，上部秸秆的剪切力明显小于其他2个部位。结论]随着玉米收获期的延迟，秸秆的纤维素和木质素含量增加，对应的剪切力增大，作为饲料适口性变差，所以应该在玉米成熟后尽早收获秸秆并进行加工处理。

S2udy on Shear!ng Force of Maize Stalk at Different Harvesting Time

Objective ] Study on mechanical properties of maize stalk can provide principal technical data for developing stalk harvesting and processing equipment of low-energy and high efficiency. Method] Shearing force of maize stalk at different harvest time was tested with uni- versal material machine, and influence of blade angle, cutting speed, sample position on shearing force were analyzed. Result] The results showed that influent order of the factors on test index（maximum sheafing force） was sample position→harvest time→blade angle→cutting speed. Shearing force decreased with decreasing of blade angle; decreased with improving of cutting speed; shearing force of root stalk was slightly larger than that of middle stalk, and shearing force of top stalk was obviously lesser than that of other positions. Conclusion] With de- laying of harvest time, lignin and cellulose content of stalk increased, corresponding sheafing force increased, feed palatability decreased, so maize stalk should be earlv harvested and nrocessed.