Test Study On Traction Of A Self-propelled Walking Brush Cutter And Its Influence On Sandlot

Brush is a type of biomass resources,and brush stumping is a major problem in Ke'erqing sandy area.The traction of brush cutter and its influence on sandplot is one of the difficulties.The feature of the soil in this area determines the suitable brush cutter which can not only provide traction but also can not destroy the vegetation which gows in the upper layer of soil.Main contents and conclusions are as follows by a vast amount of theoretical analyses and experimental researches:1.according to the requirements of brush stumping in this area such as the height after stumping,the ratio of splits and non-damage to the soil,and on the basis of structures of brush cutting equipments currently used in domestic,a self-propelled walking brush cutter was designed.A series of expriments were carried out with this machine.The results indicated that the stubble after cutting could be left under 8cm,working efficiency was 0.1 hm²h^-1,and the ratio of splits was 1.6%using this machine to cut brushes.2.Experiments were carried out to test the mechanical properties of soil.Data from soil compaction test shows that the upper layer of soil is more compact than the lower layer especially above 10cm,and its compaction data is bigger than the data from lower layer.Vegetation is subject to be destroyed by medium-sized vehicle after its passage.Thus,soil compaction is taken as an index to meature the influence of the brush cutter on sandlot in this paper.3.Experimental chasis of brush cutter and its testing system was designed.Wheel-sand dynamic interaction and the sinkage of tire was studied in the lab.Result showed traction increased with the increase of the mass of chasis,and traction increased with the decrease of tire speed.Besides,the mass of chasis has significant influence on the sinkage of tire;4.Traction of brush cutter was tested in two types of terrains in Ke'erqin.Soil compaction did not change after several times passing by brush cutter in the grass region which showed the brush cutter did not damage the surface of soil.The tractive performance was not well because of the low critical slip ratio;5.The critical slip ratio of the brush cutter was greater in the sand region on which tractive performance was better than that in the grass region.The traction was 392N in condition of 1176N vertical load.Meanwhile it damaged the surface of soil under high slip ratio which was greater than the critical slip ratio.6.Bekker's theory was applied to predict the traction of the brush cutter.and data showed the result predicted by Bekker's theory was in accordance with that from tested data.