143 - 2D FEA, It Is Simply Not Ok

Poster Board Number: 143
There are separate poster presentation times for odd and even posters.
Odd poster #s – first hour
Even poster #s – second hour

Abstract Body : Two dimensional (2D) finite element models (FEMs) of tetrapod mandibles are increasingly used in large scale evolutionary studies seeking to test hypotheses about form-function relationships in jaws. FEM is a powerful tool for testing form-function relationships in silico, replacing or extending results of in vivo experimentation. FEM requires simplification and assumptions, but this should not be at the expense of model accuracy: the model should accurately reflect the biology of the modeled system. In cases where the three-dimensional (3D) mechanics of a structure are important determinants of its performance, 2D modeling approaches produce inaccurate results: this is commonly the case for 2D FE modeling of tetrapod mandibles. Here we show that this is the case for 2D models of primate mandibles. We compared the stress regimes of our published 3D model of the chimpanzee mandible to a published 2D model of the chimpanzee mandible and identified several fundamental differences. We then performed a series of 2D and 3D FE modeling experiments that demonstrate how three key modeling parameters; (1) dimensionality, (2) symmetric geometry, and (3) constraints affect deformation and strain regimes of the models. Our results confirm that, in the case of the primate mandible (at least), 2D FEM fails to meet this minimum modeling requirement and should not be used to draw functional, ecological, or evolutionary conclusions. The widespread use of 2D FE modeling of tetrapod mandibles is ill advised as the results are likely to be inaccurate.