Node-based dynamic adaptive grid with quadrilateral and hexahedral elements

A node-based data structure is developed for use in either two-dimensional (2-D) or three-dimensional (3-D) finite element method (FEM) problems. This grid uses quadrilateral (2-D) or hexahedral (3-D) elements and is dynamica lly adaptive according to the 1-irregular requirement for refinement-derefi nement. Implemented in C + +,the grid consists of node objects linked with pointers to neighboring node objects. The algorithm used to traverse the gr id starts at the first node of the grid and constructs each FEM element by following the links of the nodes. This algorithm uses a stack to maintain t he correct order of elements during the grid traversals. Because the elemen ts and their connectivity are not permanently stored, the computer storage requirements for the grid are reduced significantly in 3-D compared with an element-based approach. Although the node-based approach may increase the CPU-time and complexity to access an element, it reduces the complexity and time required to refine and derefine an element. This implementation is ap plicable to many FEM domains. (C) 1998 Published by Elsevier Science Ltd. A ll rights reserved.