DEM Simulation And Experimental Study On Resistance Of The Sand Fixing Equipment Inserting Straws

Straw checkerboards is widely used in the desert environment remediation,which is an important engineering method in environment protection by inserting the plant stem such as wheat and haulm into sandy soil and laid checkered on the surface of the sand,so that the sand is fixed by increasing the surface roughness of the sand.Currently,some researcher have designed "sand-fixing vehicle" to realize insert straw checkerboards mechanized,but the selection of the blade working parameters mostly depend on experience.This paper aims to measure the vertical inserting resistance of the blade and sandy soil pressure by experiment and DEM simulation,then discuss the influence factors on inserting resistance of "sand-fixing vehicle",consequently,this study provide reliable basis for DEM research "sand-fixing vehicle".The main research contents and conclusions of this study are as follows:Firstly,an experiment system which can simply pressing insert straw is designed in this paper,and introduce the method of measuring parameters.The result show that the vertical steady state inserting resistance of the blade is hardly affected by inserting velocities,changed a little for different blade shapes,increased with the straw thickness;The sandy soil pressure below blade increased with the increase of inserting velocity and straw thickness,but it is almost the same for different blade shapes.Besides,the sandy soil pressure on the blade lateral show that the disturbed effect of blade on sandy soil in horizontal is more obvious than vertical.Secondly,this paper carry out the numerical model parameter calibration by experiment and DEM.The physical property of sand is calibrated by comparing the experiment result and simulation result of repose angle,the rotation parameter of straw rotate with inserting velocity is calibrated by comparing the experiment result and simulation result of straw behavior in simply pressing insert straw.Finally,this paper establishes the model of arc-blade rolling insert straws and carry out the DEM simulation.This paper assume the straw is a three-section rigid body,and all straws have the same movement which is a compound plane motion compounded by linear deceleration translation of the middle-section and linear deceleration rotation of the side-section.The simulation result shows as followings:the vertical steady state resistance of inserting straw is unaffected by the speed of blade in the interval from 4 cm/s to 10 cm/s;the vertical steady inserting resistance of the blade is proportional to laid density of straw;the steady state resistance in the vertical direction of the unit blade with a thickness from 2 mm to 6mm is in inverse proportion to the thickness of the blade.