3种杂草切割阻力试验

Cutting weed with an improved test bench and measurement of cutting resistance

对PC–B型带传动试验台进行改进:将主电机的传动轮改成切割装置,安装试验台架及夹持装置,更换更精确的压力传感器,研制出杂草切割试验台,以蒿草、狗尾草和牛筋草为材料,通过切割试验,确定杂草直径、含水率、电机转速、削切角对切割阻力的影响。结果表明,杂草切割阻力与电机转速平方成反比,与杂草直径平方成正比,与削切角平方成反比;不同杂草含水率对切割阻力影响不同,蒿草与狗尾草切割阻力与含水率平方成反比,狗尾草反之。单因素试验中,蒿草直径3.5～4.5 mm,风干10 h,含水率33.54%时,最大切割阻力为11.06 N。以蒿草为材料的正交试验结果表明,直径、含水率、削切角和电机转速依次影响切割阻力。Spss软件分析表明,在风干含水率48.53%、削切角60°、直径最大组(3.5～4.5 mm)、电机转速为最低切断转速1.2倍时为最优组合。

PC-B type belt driving test bench was improved and modified into a test bench for cutting weed by modifying the driving wheel of the main motor into the cutting and the holding device and installing a pressure sensor which is more accurate than the original one. Humilis, Setaria and goose grass were cut to determine the influence of diameter and moisture content of weed, rotational speeds of motor and cutting angle on cutting resistance. The result suggests that cutting resistance was inversely proportional to the square of the rotational speed and the square of the cutting angle, and proportional to the square of the diameter of weed. Moisture content with different weeds showed different influence on cutting resistance. In contrast to goose grass, cutting resistances for Humilis and Setaria were inversely proportional to the moisture content. Single-factor test showed that a maximum strength of 11.06 N was achieved when the diameter of Humilis was 3.5-4.5 mm, and the moisture content of Humilis was 33.54% （achieved after 10 h drying）. Orthogonal test on Humilis showed the cutting resistance was mostly influence by the diameter of weed, followed by the moisture content of weed, the cutting angle and the rotational speed of the motor. Data analysis using Spss showed that the best cutting condition was moisture content of weed being 48.53%, diameter of weed being 3.5-4.5 mm, cutting angle being 60° and the motor rotational speed being 1.2 times larger than the lowest speed.