Development of Location Specific Finite Element Head Model for the Study of Damage Progression in Head Impact Injury

Abstract

Background: Brain injuries are a primary health and a pecuniary issue all through the world. Numerical techniques like finite element (FE) methods may be used to investigate head injuries and optimize the safety, which can reduce the number of injuries. The FE head models were at first assessed for biofidelity by comparing with cadavers experiments. In any case, there are a few constraints in analyses as the body starts degrading after death. Human head FE models are mainly used for dynamic studies by creating scenarios of car crash, pedestrian & vehicle accidents in which different assumptions were considered. Objective: The aim of the research is the development of realistic FE head model to study damage progression in head impact injury under external loading, sensitivity of the head impact injury to the elastic modulus and homogenized brain modeling in response to quasistatic loading at different locations. Methodology: The FE model of the human head was used to study Von mises stress and displacement during location specific impact of the head. The human head FE model was divided into two models, one was simple and other was complex model. Both models consist of scalp, skull, spongiosa, cerebrospinal fluid (CSF), brain gray matter and white matter. These two models were then tested in three different cases with identical boundary conditions, forces and locations. Case I: Sensitivity of the injury to the elastic modulus of the brain layer by keeping all the other layers linear elastic with constant applied force to frontal region. Case II: Force Displacement Study i.e. by varying amount of force on homogenized brain model with frontal impact. Case III: Constant force was applied to homogenized brain model by varying locations of impact. Displacement and stress predicted from these models are then observed and analyzed. Results: Preliminary outcomes of these simulations show that the brain injury may occur under applied conditions for simple model and is sensitive to the complexity of geometry. The stress and displacement profiles showed lower values for the complex model than simple model. Both the models showed linear relationship between force and displacement. By varying location, the maximum stress varied and was found maximum when the force was applied from the lateral side. So it was found that lateral impacts are more injuriousix and prone towards brain injury. Thus a complex model is more accurate and showed no injury in all cases in given amount of force while the simple model showed injury in two cases with the same applied conditions