Research On The Stress Fluctuation Behavior Of Soil In The Working Process Of Bulldozing Plates

The research of soil resistance and stress fluctuation variations in the working process of bulldozing plates has important implication on the study of the design of resistance-decreasing and energy-saving for bulldozing plate.According to the curvature profile of soil surface, 5 kinds of bulldozing plate including(arc, parabolic, bionic line, cycloid and involute have been designed which have typical directrix line form. And based on the differential geometry theory of curving surface, soil-engaging surfaces for bulldozing plates were evaluated. The result shows that: the change of curvature, the first base quantity and the second base quantity of soil-engaging surfaces for bulldozing plates which have different directrix line form are different. And when bulldozing plate’s directrix line forms are same, but the cutting angle are different, the first base quantity and the second base quantity of soil-engaging surfaces for bulldozing plates are in the same basic trend, there are differences in the extremes.Establishing a finite element model of bulldozing plate-soil contact system by the finite element software ANSYS/LS-DYNA, and analyzing soil stress fluctuations around the bulldozing plates under different directrix forms and cutting angle. The result shows that: The stress fluctuation forms of soil units around the bulldozing plates in the vertical section are similar. The stress field shows a“∞”region located in front of the soil-engaging surface for the bulldozing plates. The left half of the“∞”region is a compacting stress field, and the right half is a stretching stress field. A compacting stress field is located in bottom of the soil-engaging surface for the bulldozing plates. In the range of 50°~60° in cutting angle, the mechanical properties of bionic bulldozing plate is the most optimal. In this study with five kinds of directrix line forms, when the cutting angle is 50°, the average mechanical properties of each bulldozing plate is best.In this study, the corresponding bulldozing plates are designed and produced. The test was carried out in the soil bin to investigate the soil resistance of bulldozing plates in different directrix line forms and cutting angle, and the result is compared with this obtained by the finite element analysis. The result shows that: the change trend of bulldozing plates’ working resistance measured by soil bin test is in good according with the numerical simulations of the stress fluctuations. Although there is a predictive error between soil bin test and finite element analysis, they have the same mutative tendency. The cutting process of soil by bulldozing plates can be simulated very well by using FEM.Based on the tests of working resistance on bulldozing plates, Establishing a simplified soil testing system used for test the soil stress fluctuation behavior. Drawing some conclusions according to test bulldozing plates with different directrix line forms and cutting angle by analyzing the soil stress fluctuation behavior. The changes of cutting action and bulldozing role are caused by the changes of cutting angle, so that the soil bulldozing plate arches and vaulted volatility fluctuation frequency front-end changes. The soil surface of bulldozing plates with curvature which have multiple optimal points will make soil in the front of bulldozing plates vibrate and have excellent mechanical properties.According to finite element analysis and soil bin on the soil stress fluctuation, it shows that: the variation of directrix line forms and cutting angle is in link with the soil stress fluctuation behavior directly. The change of differential geometric parameters of soil-engaging surfaces is the radical cause. The study will benefit the energy-saving design of the bulldozing plate’s ideal surface under the guidance of exploring the stress fluctuation rule.