成熟期青稞茎秆切割力的测试与分析

Test and analysis of cutting force of highland barley in mature stage

【目的】为给青稞联合收获机提供合理的设计依据,减少作业机收获时割台承受的切割阻力,降低青稞切割损失,【方法】选取收获前1、4、7 d的‘紫色昆仑17号’青稞茎秆为试验对象,以含水率、切割位置、滑切角度和切割速度为自变量,以切割力为响应值,依照Box-Behnken试验设计原理,采用四因素三水平响应面分析方法,建立了各因素与茎秆切割力之间的数学模型,并对各因素及其交互作用进行分析.【结果】单因素试验结果表明,在切割范围内(150~250 mm)含水率越低,切割位置离地面越高,所需切割力越小;在所选齿形刀的滑切角为25°时,切割力随着切割速度的增大而减小,同一切割速度下,随着切割位置离地高度的增大,切割力逐渐减小.多因素试验结果表明,含水率、切割位置、切割速度和滑切角度是影响青稞茎秆切割的主要因素,其中,含水率和切割位置对切割力影响最大,且影响切割力的因素由大到小依次是x1>x2>x3>x4,即含水率、切割位置、滑切角度、切割速度.【结论】试验结果符合预期,可为后续设计青稞收获机的切割机构提供可靠的理论参考.

【Objective】 In order to provide reasonable design basis for the highland barley harvester,to reduce the cutting resistance of the cutting table during the harvest,and to decrease the loss rate of barley harvest.【Method】 The stems of highland barley(cv.Purple Kunlun 17) of 1,4,7 days before harvest were selected as test material.The Box-Behnken experimental design with four factors and three levels was performed,the parameters such as water content,cutting position,slip angle and cutting speed were selected as independent variables,which would influence cutting force.The mathematical model was established.The effects of various parameters and their interactions were analyzed as well.【Result】 The results of single factor experiments showed that within the cutting range(150~250 mm),the lower the water content,the higher the cutting position,the smaller cutting force was required.When selected tooth knife slip cutting angle at 25°,the cutting force decreased with the increase of cutting speed.Under the same cutting speed cutting force,the cutting force reduced with the increase of height from the ground.The results of multi-factor experiments showed that the water content,cutting position,cutting speed and slip angle were the major factors affecting the cutting of highland barley.Among them,the water content and cutting position had the greatest influence on the cutting force,and the factors affecting the cutting force from big to small was x1>x2>x3>x4,that is,water content,cutting position,sliding cutting angle and cutting speed.【Conclusion】 The tests conform the expected design and the results can provide a reliable theoretical reference for the cutting mechanism of the subsequent design of the barley harvester.