Age–Related Perspectives on the Biomechanics of Traumatic Injury

Abstract: Finite element models have the potential to accurately represent the pediatric body, both from the anatomical and topological point of view. They can describe changes in size and shape as well as changes in the biomechanical properties. Starting from the PIPER human body model, whose baseline represents the anatomy of a 6 years old child, a family of five models between the age of 2 and 6 was created with the purpose of investigating how the body reacts to a traumatic impact. To create these models, a detailed knowledge of pediatric biomechanics was needed, so a deep literature research was performed to characterize all the human body tissues with age-related material properties. Then, an environment model was chosen to investigate how injuries are related to the age of the subject. Since car crashes are a leading cause of death among children, a car accident was simulated to reach the aim of the project. The anatomical and biomechanical scaling process, as well as the positioning of the child in the environment model, were performed with the PIPER tools, while simulations were run with Ls-Dyna. From the literature, age-dependent material properties were found for almost all the tissues of the human body, allowing the development of a detailed pediatric FE model. Then, biomechanical injury predictors, such as the brain strain, the skull acceleration, the chest displacement, the lung pressure and the Von Mises stress in the limbs, were extracted from the simulations to evaluate how injuries changes with the age. The head showed to be the body segment most affected by the age, with an increasing injury severity with the decreasing of the age. Moreover, it was observed that the probability of bone fractures increases for higher bone stiffness.