Meeting Abstract

12.4  Friday, Jan. 4  Finite element validation of an avian skull using ex vivo measurements CUFF, A.R.*; RAYFIELD, E.; University of Bristol, UK; University of Bristol, UK Andrew.Cuff@bristol.ac.uk

Finite element models (FEMs) have potential to describe the detailed biomechanics of musculoskeletal systems. Validation studies assist in deducing how models reflect reality, yet in avians this is particularly difficult due to thin bone, the presence of a keratinous rhamphotheca and the kinetic nature of skulls. In order to validate a FEM of a large avian skull, a computed tomography (CT) scanned ostrich (Struthio camelus) skull was dissected and an artificial tendon (carbon fiber loops embedded in resin) attached at the M. psuedotemporalis superficialis muscle site. Using a specialised rig, the artificial tendon had loads applied that were within limits ascertained from PCSA during dissection. The strains on the skull were measured ex vivo using strain gauges applied to 14 sites. Using the CT scans, the cortical bone, cancellous bone, sutures and rhamphotheca were segmented using Avizo 6.3. The surface generated was transferred into Hypermesh 10 to produce a series of models with increasingly fine mesh size (convergence testing). Using the converged mesh size, the model was loaded with identical boundary conditions to the ex vivo skull. Material properties from both the literature and nano-indentation studies on another ostrich skull were used. Results show that there are broad similarities between ex vivo measurements and models run with homogenous properties from either the literature or nano-indentation. The presence of sutures affects strains differently across the entire skull, whilst a rhamphotheca lowers strains. Principal strain alignments are also closely matched. By validating the method on avian skulls it allows more accurate parameterisation for future studies.