Date of Award
School of Engineering
Dr. Brent Nowak
Dr. Blake Ashby
Dr. Wendy Reffeor
The continued development of modern-day vehicles has allowed innovators to shape their design to meet the consumer’s requirements. Vehicles have become faster and larger to accommodate more passengers and their belongings. The increased popularity of Light Trucks or Vans (LTVs) and Sports Utility Vehicles (SUVs) elevated their sales to approximately 50% of all vehicles sold in the United States by 1999 . These advancements have created a high-energy world, which poses a serious threat to the ever-growing population. Unprotected pedestrians come in all too frequent contact with these vehicles creating the potential for high-energy blunt force trauma. This thesis aims to prevent the deadly result of pedestrians suffering LTV impact from the rear through the design, analysis, development, and test of a protective wearable device. The metrics of evaluation of the impact scenario were average acceleration and spinal hyperextension.
This work employed analytical analysis, finite element analysis, and experimental testing methods to develop the device. Elements of the design and its association with advanced materials gave the proposed device novelty. Experimental testing was accomplished through a drop test series using a mock human model. Full height testing simulated a vehicular collision at 20 miles per hour. Data were collected through acceleration measurements and high-speed video analysis. Statistical analysis of the impacting event showed an appreciable decrease in acceleration and a significant reduction in dynamic hyperextension. The average acceleration during initial impact was decreased by 14% and hyperextension was reduced by 81%.
The resulting peak acceleration surpassed the NHTSA’s Thoracic Injury Criteria (TIC) criteria of 60 G’s but not the suggested Thoracic Trauma Index (TTI) level of 85 G’s  . These criteria are identified as exceeding the set level for a time interval longer than 3 ms. Reducing peak acceleration to within these limits was found in literature to reduce the probability of severe internal damage . The significant decrease in hyperextension reduced the deflection to an acceptable range of the human spine and would prevent the pedestrian’s head from impacting the hood of the vehicle. These results combined with an ergonomic functional design supports the proposed device as a feasible and capable protective measure against high-energy blunt force trauma.
Schaefer, Samuel B., "The Design, Analysis, Development, and Test of a High-Energy Trauma Prevention Safety Device" (2018). Masters Theses. 917.