Shear Properties Of Discrete Element Research Of Wheat

Ranary of the unloading process is affected by the gravity of grain.Food particles and particle to particle interaction with the warehouse wall make the dynamic pressure is greater than the static pressure caused by the warehouse wall.The gravity is one of the main load of silo structure design.Commonly,we get parameters by indoor experiment to calculate the load.But,it is difficult to completely show the warehouse in different stages of mechanical characteristics through indoor test.Need to study with the help of numerical method.Based on wheat as the research object,this paper applied the PFC3 D numerical experiments to study the shear properties of food.We get the relationship between macro parameters and mesoscopic parameters of wheat through numerical test results and laboratory test data matching.Studied the strength parameters of the grain and the dilatancy property are analyzed from the Angle of mesoscopic.In this paper,the concrete research content is as follows:(1)According to the existing indoor triaxial test results of wheat,using PFC3 D bring fish language programming,preliminary selected need to mesoscopic numerical model is established and the parameters.Using the established numerical test sample,the mesoscopic parameters is studied.The relationship between the Angle of internal friction of wheat and friction coefficient of particles is calibrated.(2)This paper study the relationship between the secant modulus E50,the initial tangential modulus E and the particle stiffness.E50,E and the particle stiffness act as power function development.The secant modulus E50,initial tangential modulus E has a linear proportional relationship.E50,deviatoric stress peak value with the increasing of stiffness ratio act as a linear relationship.(3)According the relationship between macro-mesoscopic parameters established,match the results of numerical experiment and indoor triaxial test results.Results show that under the condition of the three different confining pressure,the results of numerical test and indoor triaxial test results of wheat is better.(4)On the basis of the numerical experiments of the existing research,the preparation of the numerical test samples of different porosity made.Then make them under different confining pressure respectively.Through the results,we get the Mohr-coulomb strength envelope,thereby ret c and?under different porosity condition.(5)This paper study the changing relationship between the porosity and confining pressure with the dilatancy Angle and poisson's ratio,the influence of the transformation point location.For shear dilatancy phenomena in the process analyzed from the perspective of mesoscopic.Also,explained the different between the results of numerical test and the indoor triaxial test results of wheat.