Modeling, experiment, and validation of a piglet head

Abstract

Introduction

Traumatic brain injury (TBI) is a prevalent type of disabling and fatal injury in infants/toddlers, which is usually caused by falls or traffic accidents. Considering that it is difficult to collect realistic material properties and validation data of child heads due to ethical reasons, experiments on the piglet heads and the finite element (FE) models are generally used as a substitute for the investigations of child TBI.

Methods

In this study, first, a high-quality FE model of a 4-week-old piglet head, including brain (cerebrum, cerebellum, brainstem), skull, soft tissue, cerebrospinal fluid, dura matter, pia matter and mandible, is developed. Then, test for the material properties of the piglet head and that for the global validation data are conducted. For the former, the mechanical properties of the brain, overlying soft tissue and skull of the 4-week-old piglet head are tested, and the constitutive models and corresponding parameters are further defined. For the latter, the quasi-static compression test and dynamic impact test (free-fall drop impact test, drop-hammer impact test) are performed on the piglet head. Finally, the piglet head FE model was validated against tests in terms of the contact force and intracranial pressure (ICP) under eight conditions (one for the compression condition, four for the free-fall impact condition, and three for the drop-hammer impact condition).

Results

The trends of simulated curves are consistent with the experimental results under all conditions. For the contact force, the average error of the peak values between simulations and tests is about 12.9 %, and the average error of time durations is about 6.8 %. For the ICP, the average errors of peak values and time durations between simulations and tests are about 8.9 % and 9.9 %.

Conclusions

The results show that the piglet head model has high bio-fidelity, which can be used to predict the head global response and the ICP, and further to assist the investigation of child TBI. The model provides another effective way to evaluate the modeling strategies and material constitute models suitable for child head FE model, and can better to understand the inducement and mechanism of child TBI under different external loading conditions.