Pii: S0965-9978(98)00069-6

A node-based data structure is developed for use in either two-dimensional (2-D) or three-dimensional (3-D) ®nite element method (FEM) problems. This grid uses quadrilateral (2-D) or hexahedral (3-D) elements and is dynamically adaptive according to the 1-irregular requirement for re®nement±dere®nement. Implemented in C 1 1 , the grid consists of node objects linked with pointers to neighboring node objects. The algorithm used to traverse the grid starts at the ®rst node of the grid and constructs each FEM element by following the links of the nodes. This algorithm uses a stack to maintain the correct order of elements during the grid traversals. Because the elements and their connectivity are not permanently stored, the computer storage requirements for the grid are reduced signi®cantly 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 re®ne and dere®ne an element. This implementation is applicable to many FEM domains. q 1998 Published by Elsevier Science Ltd. All rights reserved.