Research Of Analysis Methods For Mechanical Components In Complex Structure And Movement Mode Based On DEM

In the field of design and manufacture, traditional design for mechanicalcomponents gets satisfactory results through repeating the process of design, test,revising the design, which is time-consuming and laborious, and it may not be able toreach the ideal target. While using the computer simulation technology to transfermechanical parts design to the computer simulation platform, not only can solvedisadvantages of traditional design method, but also make the design and manufacturefor mechanical parts got a certain scientific basis.However, because of a large presence of granular materials in industrial andagricultural production, such as crop seeds, fertilizer, drug particles, it can not getsatisfactory results of the simulation for mechanical parts when use traditionalcontinuum mechanics method (CMM) to analysis particles’ movement condition. Thediscrete element method (DEM) is proposed by Cundall in the nineteen seventies end,and has became a general method on researching particles’ dynamics problems. Thebasic idea is, granular materials are simplified into a certain shape and quality of theparticle set, then give each contacted particles, the particle and the boundary somecontact mechanical model and parameters inside the model. Therefore, it used toconsider the interaction between the particle-particle and the particle-boundary anddifferent physical properties between the particle and boundary. Discrete elementmethod can analysis different process by different contact mechanics model, so it hasbeen widely used in different study fields.It requires to establish DEM analysis model for mechanical components whentakes the analysis of DEM, in addition to the establishment of granular material model.But so far, the attention to the boundary modeling is still relatively small in discreteelement method. In this study, on the basis of the establishment of DEM analysismodel based on the Pro/E software, it going to research the establishment of theboundary model under UG environment. At the same time, the analysis method ofDEM for mechanical components in complex movement mode was probed.For basic graphics in CAD model, such as plane, sphere, cylinder and conesurface, they can express by elementary analytic function and build boundary model according to the graphic related geometry. But to the boundary model of complexmechanical parts structure, it cannot use analytic formula like basic graphics toestablish their boundary model. In the paper, complex curved surfaces are meshed bythe direct method based on the advancing front technique. And with the application ofUG/OPEN program-developing tools in UG software, the analysis model of DEM isestablished for complex mechanical parts structure.Except simple motion mode, such as translational, rotational and compositemotion of both, it often includes complex movement mode in industrial andagricultural production. The complex movement mode is essential in mechanicalproduction, but the simulation in complex movement mode is not the same as thesimple motion mode which can get the motion law directly by the generalmathematical method. Therefore, this paper uses the kinematics analysis method ofmulti-body system to build analysis model for complex movement mode mechanicalparts. The motion process data obtained through linear and nonlinear numericalcalculation method. And it combined with OpenGL graphic library to achieve thesimulation for mechanical parts in complex motion mode. Then the DEM calculationand simulation for mechanical components in complex movement mode was realizedaccording to the team’s research on DEM analysis technique.Based on the above theory, method and the research by the work group, the paperdeveloped the analysis software of DEM for mechanical parts in complex structurewith different CAD model according to the design demand and software designprocess. And designing computation and simulation function of DEM in complexmovement mode for mechanical components according to the kinematics ofmulti-body system analysis method. At the same time, the representational test case inprogramming process is given. Instance test for analysis model of DEM in complexboundary and complex motion is verified, which is further proof of the correctness,feasibility and effectiveness of the software.In summary, the DEM boundary modeling method proposed in the paper has itsuniversality, which can be convenient to establish analysis mode of DEM for differentcomplex mechanical parts. The designed calculation and simulation function of DEMin complex movement patterns in the software has obtained good effects, which areclose to actual results, and it ’s proved the method and development of the software isfeasible.