Effect of Horizontal Plate Length on Cutting Resistance of Blade Under Different Cutting Depths in a Sandy Soil

Blade shape affects the cutting resistance of the blade, and it can be designed to reduce the cutting resistance. In this study, two types of blades (I-type blade and L-type blade) with an identical rectangle profile projection (width 300 mm, height 500 mm) were compared by experiment of soil cutting. The cutting rake angle of the blades is fixed at 90° to ignore the vertical cutting resistance, and then, we can only focus on the horizontal cutting resistance which can be regarded as the drought force. Thirty groups of soil cutting test were carried out in a soil bin filled with sandy soil in which the moisture content was neglected, and cutting depths considered were 30, 60, 90, 120 and 150 mm. The effects of the cutting depth and the horizontal plate length on the cutting resistance of the blades were studied. The results showed that the cutting resistance increases with the increase in the cutting depth, which present a curvilinear relationship for each blade. When the cutting depth is the same, cutting resistance decreases firstly then rises with the increase in the horizontal plate length. Therefore, it can be believed that the L-type blade must have an optimum shape for soil cutting. In 25 group comparisons between five L-type blades and the I-type, the L-type blades presented lower cutting resistance in 23 group tests. However, the optimal shape in the present study is that the L-type blade length is about 45 mm for different cutting depths, which can make guidance for us to design the shape of the blade.