Wilson and Taylor developed nonconfonning 4-node quadrilateral elements which satisfy the patch test for arbitrary element shapes and offer improved behavior in bending. Their detailed development has appeared in standard FEM text books. While these sources note that the extension to three dimensions is straightforward, the present authors have not found details of the corresponding three-dimensional hexahedral element readily available in the literature. The work in this paper was motivated by the need for an efficient 3-D element for simulation of the response of strapdown gyroscopes for which bending behavior is dominant. While 20-node hexahedral elements would suit this purpose, their additional computational demands are a disadvantage. Thus, the present authors have developed an 8-node, nonconfonning, hexahedral element for use in the in-house FEM program BAMAFEM intended for use in simulating gyroscope response. Details are included so that others can easily use such an element if desired. Modifications for the element to satisfy the patch test for arbitrary shapes are detailed. The behavior of the 8-node, nonconfonning hexahedral element is compared to that of a standard 8-node hexahedral element and also to that of a 20-node hexahedral element for a three-dimensional modal analysis. The ALGOR code is used for comparison.
展开▼
