Faithin Omaha eBook Collection

Download or read book Traumatic Brain Injury (TBI) Prediction in Pedestrian Collisions written by Kyle A. Ott and published by . This book was released on 2005 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Pedestrians account for roughly 12% of all motor vehicle related fatalities in the United States, which equates to approximately 4,700 deaths per year. Head injuries are the most common cause of death in these accidents. Current test procedures around the world involve launching a projectile headform into vehicle structures to assess aggressiveness toward pedestrians. The Head Injury Criterion (HIC) uses linear accelerations from a pedestrian headform to assess impact severity, which is in turn dictated by the head impact velocity and vehicle stiffness. Vehicle exterior contours or underhood structures often impart a rotational component to the headform upon impact as well as affecting the wrap around distance (WAD). In the past several years, evidence has indicated that these types of rotational accelerations influence injury. The objective of this study was to examine the relationships between vehicle characteristics and head injury using a combination of computer modeling, experimental testing, and accident data. Analytical tools could then be constructed based on these quantified relationships to facilitate pedestrian-safe vehicle design. A multi-body, finite element-based headform model has previously been developed to exhibit response characteristics consistent with the International Harmonization Research Activities (IHRA) adult and child pedestrian headforms. In the current study, a series of simulations with this model was conducted using a wide range of impact velocities and stiffness values, producing a distribution of HIC values. Experimental test data was used to determine where a sample of the U.S. fleet falls in the simulated HIC matrix. The second phase of this research involved the investigation of head injury mechanisms through case reconstruction. Full-scale pedestrian case reconstructions were done in MADYMO to acquire linear and angular accelerations of the pedestrian's head. These accelerations were then entered into the Simulated Injury Monitor (SIMon) algorithm to predict brain injury based on both translational and rotational acceleration. These predicted injuries were then compared to those documented in the case. The third phase of this study involved the relation of certain accident geometric parameters to injury using statistical software to analyze the Pedestrian Crash Data Study (PCDS) data and derive relations. This would help lead to an equation that would predict probability of brain injury based on certain geometric characteristics. Three different tools were developed from this study. The first tool is a HIC predictive algorithm that gave HIC as a function of head impact velocity and linear stiffness. The second tool is a reconstruction process through which both traumatic brain injury and skull fracture may be predicted. The third tool is a relation between WAD as a function of vehicle impact speed and top transition point normalized by pedestrian height as well as a set of probability curves of injury as a function of vehicle speed.