Research On The Working Performance Of Grader Blade Based On The Discrete Element Method

As one of the most important earthmoving construction machinery, grader is widelyused in the farming land and airport where there are large flat workplaces. The blade is themost important working device of grader. In view of the complexity of geotechnicalstructures, and inhomogeneity of stress, the blade is susceptible to wear and tear. So it isvery necessary to study on the blade force under different geological conditions. Blockmodeling is used to analyze the load distribution of the blade during the working process tobasically optimize the blade structure and then find the most reasonable parametercombination from the four factors of the blade cutting speed, cutting depth, blade radius,cutting angle using the method of orthogonal, which can be used to guide practical bladedesign. The main research contents of this paper include:1. Introduce the working device structure of the blade and the relevant parameters ofthe blade during the working process. Make preparation for selecting the level and factorsof orthogonal experimental design.2. Grader working medium model is established. The sand and stone are used as theworking medium of grader, and the model of the grain contact model was established by themode of Hertz-Mindlin and BPM under the environment of DEM. The method of directshear test is used to acquire macroscopic parameters of the sand model, and the method ofthe test of natural angle of slope is used to verify the accuracy of the model. The method ofuniaxial compression test is used to acquire microscopic parameters of BPM rock key.Using the above parameters to establish sand and rock model to prepare for the next step ofsimulation.3. The stress distribution of the blade is analyzed, which provides the basis for thestructural design of the blade. First the blade block model and sand medium model areestablished, then the simulation is executed in the DEM environment. Simulation resultsshow that: the stress on the upper part of the blade shows a parabolic distribution., the stresson the middle part of the blade shows basically at the same level., the bottom part of the blade is influenced by the soil cutting resistance on both sides, which results the stress ofboth sides are significantly higher than that of the middle. Therefore, in order to savematerial, the blade model is designed into the shape, whose middle part is higher than bothsides of the blade, a reinforcing plate is created on both sides of the blade, and the rib iscreated on the bottom of the blade..4. The influence of cutting resistance on grader blade is analyzed which is influencedby cutting speed, cutting depth, blade radius and cutting angle during the work. Afterfinishing the blade model and rock medium model, the influence of various factors on theworking resistance of the blade is acquired by the orthogonal test and the optimalgeometrical parameters and working parameters of the blade is acquired. The results showthat: the influence of various factors on the blade resistance is listed by the size of thecutting depth, cutting speed, blade radius, cutting angle. And the proportion of the fourfactors influencing is35.6%,29.8%,18.2%,16.4%. With the increase of speed and thecutting depth, the stress of the blade increased. When the cutting angle is about40degrees,the force is small. When the blade radius is413mm, the stress is minimum, which providesthe basis for the optimization of the blade.