Feature-Based Modeling, Graded Meshing And Mid-Plane Extraction For Plastics Injection Mold CAE

In order to solve some key problems for using plastics injection mold CAE techniques, the research of feature-based modeling, graded meshing, and mid-plane model extraction are studied in this dissertation. These work have been programmed and integrated into a plastics injection mold CAE software, which makes the using of CAE software convenient and fast. The main results is following:(1) A method of feature-based mid-plane modeling is proposed by means of feature classification. This model includes the information about geometric modeling, meshing, and simulation, which put mid-plane model and FEM meshing into a body. It makes mid-plane modeling, meshing, and correction to the model more convenient and faster.(2) The Advancing Front Method is adopted to generate graded mesh on arbitrary plane using a new mesh size dynamically controlling method. The result triangles have higher quality and smooth transition to different sizes. If the mesh size at one point, one line segment, or one region is defined, the program will generate automatically. A triangulation is finished on a parametric field for a curved region, and a graded mesh can be generated for some ordinary ones.(3) A methods for generating uniform mesh and graded mesh is proposed on a parametric field for some curved regions. This method is efficient and the resultant triangles have good quality. Because the methods are suite for many curved regions, it can meet the requirement of FEM computation in ordinary occasions.(4) Based on a STL file of thin-wall part, which can be produced by almost each commercial CAD software, an algorithm is proposed for Mid-plane mesh model extraction. By this technique, a higher qualitative surface triangle mesh suited for FEM is attained after re-meshing. Not only the mesh can be used to two-domain flowing analysis, but also used to extract the mid-plane model for the mid-plane flowing simulation.(5) Based the surface mesh of a solid, a mid-plane model is extracted which is suited for plastic injection simulation. By this technique a solid model out of CAD software is directly used to flow analysis ,which makes it possible to integrate CAE with CAD.(6) A visualization method is proposed to display the mesh model and the simulation resultant data fields of plastics injection mold CAE, which include colorisograms, color nephogram and computer cartoon. These provide some valid tools to better understanding a great deal of data which comes from FEM computation.