AN IMPROVED METHOD FOR FINITE-ELEMENT MESH GENERATION OF GEOMETRICALLY COMPLEX STRUCTURES WITH APPLICATION TO THE SKULLBASE

An automated method has been developed to generate finite element mesh es of geometrically complex structures from CT images using solely hex ahedral elements. This technique improves upon previous voxel-based me sh reconstruction approaches by smoothing the irregular boundaries at model surfaces and material interfaces. Over a range of mesh densities , RMS error in surface Von Mises stress was higher in the unsmoothed c ircular ring models (0.11-0.24 MPa) than in the smoothed models (0.080 -0.15 MPa) at each mesh density. The element-to-element oscillation in surface element stress, as measured by the average second spatial der ivative of Von Mises stress along the outer surface of the ring, was h igher in the unsmoothed models (11.5-15.0 kPa mm(-2)) than in the smoo thed models (4.0-6.8 kPa mm(-2)). Similarly, in a human skullbase mode l, the element-to-element oscillation in surface Von Mises stress was higher in the unsmoothed model (5.52 kPa mm(-2)) than in the smoothed model (1.83 kPa mm(-2)). Using this technique, finite element models o f complex geometries can be rapidly reconstructed which produce less e rror at the surface than voxel-based models with discontinuous surface s. (C) 1997 Published by Elsevier Science Ltd.