The Research Of A Method For Representing Boundaries Of 3D DEM Based On The Software Of AutoCAD2007

This dissert has summarized and analyzed the inner and abroad research of the DEM and the modeling methods of the model, founding that it is important and difficult for the DEM boundary modeling researches and the exploiting of the commercial discrete element software which build the boundary discrete element models with complicated structures, different dimensions, and a variety of movement styles. So an idea of building the 3-Dimension (3-D) DEM analysis models from the 3-D CAD models of the mechanical components boundaries is given, which conquer the defects of the traditional 3-D discrete element software boundary models, such as the simple structure, fixed dimension, and disability of adding complicated movement styles. This method also achieves the integration of the AutoCAD software and the self-developed software of 3-D discrete element calculation analysis and simulation. An integral analysis design system of the general mechanical components integrates the structure dimension designs and the performance analysis evaluations. A great amount of 3-D discrete element computing and simulating experiments and programming demonstrations have been done to validate the feasibility and correctness of the idea.Based on the Visual LISP exploiting language, using the inner command of the AutoCAD to transfer the graphics boundary information dada and in the process of recognizing the model information of the 3-D mechanical models, this article presents a method called graphics recover to recognize the figures and pick up the boundary of the irregular graphics. According to this idea, the independent graphic element of the mechanical models is picked up randomly, with its type information recognized and the geometry parameters information achieved, and then, with the movement analysis model of the 3-D discrete element boundary, the predefined moving property and the material property information is added to the 3-D mechanical components; Then, the geometry information and movement and material property information of the 3-D mechanical components is picked up and stored in the outer data base; After that, the 3-D discrete element software will read the graphic element information including the geometry information, movement information and the material information, which is stored in the list of the data base, and build the computing examples of discrete element method for very graphic element; Finally, every examples is stored and is used in the 3-D DEM calculation and the simulation display of the computing results. With all the work above, a 3-D boundary DEM analysis model is built up, which include the topological geometry model, kinemics model and the material characteristic model of the 3-D boundary of the mechanical components.The advantages of building up a 3-D DEM analysis model from the 3-D CAD model of mechanical component boundary are:â‘ In the process of designing the mechanical components, the boundary DEM analysis model of different structure characters and dimension parameters and a variety of movement modes can be modeled by modifying the 3-D CAD models, and the structure analysis and performance evaluations are completed by doing the discrete element calculation simulation experiments, which can achieve the optimization and adjustment of the mechanical components structure scheme and dimension parameters;â‘¡In the DEM calculating simulating experiments of the 3-D CAD models of the mechanical components, the analysis of the working theory , the inventions of the new mechanical components with the help of the specialists experiences and the illumination rules and the integration of the designs and evaluations are the things that other existing commercial 3-D discrete element software can not achieved;â‘¢The 3-D discrete element calculating modules can be integrated to the AutoCAD software itself, enriching the functuons of the AutoCAD.