Improved Modeling Of Non-spherical Patricles And Conveyors Work Process Analysis Software Development

Granular or bulk materials are belonging to a category of widely-used substances, so theresearch on this material is of great significance. This particulate matter has fixed shape andvolume, and also has discreteness and flowability, so conventional solid research methods arenot suitable for the particulate material.Discrete element method which is based on Newton’s second law is proposed by Cundall,it provides a new way of thinking for particle motion research. After years of hard study, theresearch group has achieved great results in the discrete element theory and simulation. Theresearch group has developed a simulation software using discrete element method whichintegrates design, calculation, simulation demonstration and performance analysis together,and has accumulated a wealth of experience. Objects of software emulation has progressivelydeveloped from the simple particles and agricultural machinery to irregular particles andcomplex machinery.The method of particle simulation that originally used by research group was based onPro/E graphics, and human-computer interaction is manually used to adjust the size and thenumber of spheres in order to complete the combination sphere modeling of non-sphericalparticles. Although this method can create a more complex shape of the particle model, theaccuracy between the model and the real object can’t be well guaranteed only via judging bynaked eyes and modeling. So the research group uses the three-dimensional scanner data fileas the input, and establishes an generation algorithm in which irregular particles are filled byspheres basing on vertices and triangular mesh surfaces. This method is more precise in fillingcomplex three-dimensional particles, but the number of filling spheres is so large whichmakes the computing efficiency very low, therefore, the combined particles cannot be used inscientific computing. Though the original program can reduce the number of filling spheres,since the optimization method is not very good, it will lose a lot of local information of theoutline feature of irregular particles when the number of spheres decreases.Basing on the serious research of the scanning file optimization method, this paperoptimizes the point-cloud-based and triangle-based modeling method by choosing moreappropriate point cloud simplification method depending on the precision of userrequirements. Meanwhile, the new module of automatic sphere-filling modeling for ellipsoidand hypersphere is added. This module requires user to input parameter equation of ellipsoidand hypersphere, then regular point cloud is firstly generated, and finally spherical particlesare generated basing on the filling thought of irregular particles. Also, depending on the user’schoice, the type of the particle can be determined(irregular particle, ellipsoid or hypersphere), then the same mass or density is entered. and the data such as axial length of the particles andthe information of constituent spheres will be stored in the database. The particles can be usedas the particle templates of discrete element calculation.Also a conveyor working process simulation software is developed in The paper. Firstconveyor simulation software needs are analyzed, and the system data flow diagram, use casediagrams and program design are demonstrated. multiple conveyor model extracted fromCAD software is used to set up the boundary model. According to the characteristics ofdifferent conveyor movements, correct movement is given to the boundary at different times.at the same time, a large number of particles are generated in the conveyor, which can verifywhether the conveyor work in the prescribed manner.Finally, the modules and functions are tested according to the method of software testing.The test results show that optimization modeling program for non-spherical particlesproposed in this paper can set up the model of non-spherical particles in the case ofcontrolling the number of spheres and ensuring the accuracy. Users can input parameterequation of ellipsoid and hypersphere, then the non-spherical particle modeling software canautomatically generate composition spheres. Conveyor working process simulation softwarecan simulate conveyor work processes according to CAD design drawings made dependingon user inputs and operate stably, which implements the function of conveyor simulation.