Toshimitsu Fujisawa

A FEM-BASED MESHFREE METHOD WITH A PROBABILISTIC NODE GENERATION TECHNIQUE

In this paper, a FEM-based meshfree method with a probabilistic node generation technique is presented. In the proposed method, all computational procedures, from the mesh generation to the solution of a system of equations, can be performed seamlessly in parallel in terms of nodes. Local finite element mesh is generated robustly around each node, even for acute boundary shapes such as cracks. The algorithm and the data structure of finite element calculation are based on nodes, and parallel computing is realized by dividing a system of equations by the row of the global coefficient matrix. In addition, the node-based finite element method is accompanied by a probabilistic node generation technique, which generates good-natured points for nodes of finite element mesh. Furthermore, the probabilistic node generation technique can be performed in parallel environments. As a numerical example of the proposed method, we perform a compressible flow simulation containing strong shocks. Numerical simulations with frequent mesh refinement, which are required for such kind of analysis, can be effectively performed on parallel processors by using the proposed method.

Node-based parallel computing of three-dimensional incompressible flows using the free mesh method

The present report discusses node-based parallel computing of three-dimensional incompressible flows using a node-based finite element method named the free mesh method (FMM). The FMM has two advantages over the finite element method. One advantage of the FMM is that this method is quite suitable for massively parallel computing because all computational procedures, from the mesh generation to the solution of a system of equations, can be performed in parallel in terms of nodes. Another advantage of the FMM is that finite element mesh is not required as input data so that the analyst need only prepare data concerning the nodes in the analysis domain. The present method is implemented on distributed memory systems, such as a parallel supercomputer Hitachi SR8000. The performance of the proposed method is demonstrated by computing a lid-driven cavity problem. A numerical example is used to show that the FMM can achieve high parallel performance by a simple distribution operation of computational loads among multiprocessors.

VCCM Rule-Based Meshing Algorithm for an Automatic 3D Analysis of Crack Propagation of Mixed Mode

An analysis of crack propagation using FEM need to perform re-meshing for an updated shape of crack with each cycle. In an analysis of crack propagation of 3D mixed mode, the shape of crack seems to be complex. In addition, we must effectively calculate parameters of fracture mechanics and exactly forecast a direction of crack propagation.