Three-dimensional Mesh Generation Research Articles

Three-Dimensional finite element mesh generation using delaunay tesselation

A new method of three-dimensional finite element mesh generation is presented in this paper. The method is based on an extension of the Delaunay triangulation algorithm to three dimensions, Using the mesh generator, problems are defined by means of simple three-dimensional solid modeling commands. Mesh generation is performed automatically from the objects entered. Various two and three-dimensional Delaunay mesh generation algorithms are also compared and insights to robust mesh generation provided.

Computer modeling of the human left ventricle.

A computer graphical technique is described for reconstructing the three-dimensional geometry of the human left ventricle of the heart from biplane cineangiograms. The views used are right and left anterior oblique. The reconstructed shape is intended for three-dimensional mesh generation for finite element stress analysis, but may also be useful for clinical diagnostic purposes and for cavity volume calculation throughout the cardiac cycle.

A Solids Mesh Generator and Result Display Package

The paper describes a three-dimensional mesh generator aimed at complex solids, using a mini-computer in conjunction with interactive graphics. The principles of operation are: 1 – The solid is divided into subregions, each generated from key point coordinates. 2 – Interfacing of the subregions can easily be accomplished by the user. 3 – Numerical information may be obtained regarding any of the nodes or elements. 4 – The generator is attached to a standard Unified Data Base to enable interfacing with analysis packages. 5 – Different materials may be used and stored as part of the data base. 6 – Provisions are made for substructures and reduced substructures. 7 – Graphics display is based on minimizing screen information for best effectiveness. 8 – Software rotation and perspective including depth. 9 – It is possible to display arbitrary sections based on topological or geometrical considerations. 10 – Stresses and deflections may be displayed and screened.

Multiple Shot Analysis In Shot-peeningUsing Finite Elements

A computer program OB AID has been used to analyze complex target plate and allows for dynamic loading due to impinging single and multiple shot. Theoretical model using three dimensional isoparametric finite element has been presented, in which a provision is made for the surface hardening and cyclic impact loading caused by multiple shots. Theoretical model agrees reasonably well with other models. INTRODUCTION Shot peening is viewed as a process involving multiple and progressively repeated impact. The object is to include compressive residual stresses in the surface of the target. A general form of residual stress in a typical shot-peening operation is shown in Figure 1. The impact of spherical shots, which usually takes place at a high velocity 100 m/sec, also causes plastic deformation which results in changes in the mechanical properties in the surface material. An extensive work has been carried out by several authors [1-12] to model the process. An attempt to modelize the process, in viewing as process involving multiple repeated impact. When shots impinge upon a target of elastic/plastic material and the impact velocity is sufficiently high, the target material below each impact undergoes local plastic deformation and, upon rebound, the rest of the elastic material tends to push the plastically deformed zone resulting in compressively applying numerous impacts over the whole surface, the target acquires a shallow layer of superficial compressive residual stress below which it develops smaller equilibrating tensile stresses. This paper attempts to present theoretical model using three dimensional isoparametric finite element, as will be seen, it surprisingly agrees reasonably well with other model. [1,2] THREE-DIMENSIONAL FINITE ELEMENT MESH GENERATION The finite element mesh for the target plate is shown in Fig. 2. In order to produce accurate residual stresses, it has been decided to divide the thickness of the target steel plate into nine layers (in the Y-direction). The plate thickness below the Transactions on Engineering Sciences vol 2, © 1993 WIT Press, www.witpress.com, ISSN 1743-3533