Bao Yidong

Mesh Generation Based on Virtual Geometry

Finite element mesh generation algorithm often requires the ability to abstract and modify the topology of a boundary representation model. A method based on virtual geometry for mesh generation is proposed to modify the model topology without changing the geometry of the model. By this method, a tool is given to adjust the model topology for optimal meshing, while leaving the geometry or shape of the model, and the accuracy of the resulting mesh in representing the model, unchanged. Our practical examples show that the proposed method is effective and reliable for mesh generation in molding analysis field.

QuickForm Simulation System of Sheet Metal Forming with Trial‐and‐error Contact Algorithm

The QuickForm numerical simulation system has been self‐developed specially for sheet metal forming with complex geometries. In order to resolve the convergence problem of static implicit method due to the change of contact state, the uncoupling solution method of the non‐linear differential equations is used in QucikForm system. The bending effect and drawing effect during forming procedure are separated into two independent processes in QuickForm system. During bending effect solution, the contact state between the blank nodes and rigid tools should be determined by accurate contact algorithm. A trial‐and‐error contact algorithm is used in the bending effect calculation process of QuickForm system. The contact procedure is carried out before the solving of bending effect FEM equations, and the contact conditions are treated as the boundary conditions of FEM equations. Numerical simulation results of complex part demonstrate the higher efficiency and accuracy of this contact algorithm and the proposed sp...

Shape Modification by Beam Model in FEM

Abstract Shape modification and deformation play an important role in the filed of geometry modeling, computer graphics, conceptual design and so on. A novel physically based shape modification approach is presented in this article, with beam model in finite element method (FEM). By means of interactively creating a beam with circle cross section based on pre-defined local coordinate system, the primitive geometry model is embedded in the beam globally or locally. After imposing external loads, such as concentrated force or couple, on selected nodes, their displacement can be computed. Moreover, deflection, axial deformation and twist angle of beam model can also be interpolated using shape function matrix. As a result, object is modified as a part of beam. The proposed approach is linear, simple and fast, by which stretch, bending, taping and twist deformation can be accomplished. Finally, some experimental results are given to demonstrate that the presented method is potentially useful in geometry modeling and shape design.