1. Doug Browne Jeff Markle Tyler Severance

2.  Subdural hemorrhaging occurs when the blood vessels that connect the dura to the brain rupture  This can happen when the brain moves relative to the dura, causing the connecting vessels to stretch and burst  Due to a higher density of CSF relative to brain tissue density  The maximum strain was found in research and verified in Vanderbilt cadaver lab during advisor guided dissection

3.  From cadaveric studies, the connecting blood vessels undergo permanent deformation at 20% strain and total rupture at 150% strain which occurs at accelerations between 4,500 and 10,000 rad/s 2

4.  Already proven that collisions in football often exceed dangerous levels of rotational acceleration  In all levels of football (high school, college and professional) top 1% of collisions reach critical levels of rotational acceleration  Collisions cannot be prevented without drastic change in the sport; however, helmet design can be modified

5.  The National Operating Committee on Standards for Athletic Equipment is the governing body that regulates standards for football helmets.  Helmets are only required to prevent against levels of translational acceleration that would cause skull fractures.

6.  Tests helmets for NOCSAE and does a lot of independent research on helmets.  Met with Technical Director David Halsted who shed light on many problems with designing a new, improved helmet

9.  Helmet it not well coupled to the head during a collision  Athletes can suffer brain injury even when head is not involved in the collision  Current helmets are effective at dampening blows to the head (difficult to improve upon), but this is a different issue than lowering overall angular acceleration

10.  After meeting with Dave Halsted, it became apparent that this problem is more complex than was initially predicted  He mathematically proved that changing cushion design would have minimal, if any, impact on helmet function

11.  After meeting with Mr. Halsted, it became apparent that this problem is more complex than we initially imagined.  Together, we identified three main issues our team could “tackle”  Helmet weight  Relatively large range of motion  Detection of potential brain injury

12.  Lightweight helmet that keeps the same levels of protection against linear acceleration as current models  Include in the helmet a device that indicates when dangerous levels of rotational acceleration have been reached.  Attempt to create a seat belt based design to prevent the head from reaching the peak levels during the collision

13.  The seat belt theory has potential, but a helmet alone won’t regulate the motion  Shoulder pads can be included to transform the system from just a head to the entire upper torso  Perhaps it will be possible to tether the helmet to the pads + = + ?

14.  Another issue that can be addressed is that a significant number of subdural hemorrhages are undetected (sources vary widely )  Possible to create a safety feature that would indicate when dangerous levels of acceleration have been reached  Apply accelerometers to the back of the helmet which could signal that a player should be removed from play and examined by a professional

15.  We are currently developing a prototype helmet that will be able to be tested using the equipment at the SIRC  Taking/modifying elements from different current helmets so we don’t have to manufacture many new parts  Attempting to procure a set of shoulder pads to use in our design  Via local high schools  Searching for suitable accelerometers to use as a potential indicator  Continuing to run ideas by Mr. Halstead to assess our progress  Planning a future trip to Knoxville for more testing

16.  If all goes as planned, we will have a working prototype that can be tested by the end of March  Further testing and modification can occur as needed for the rest of the semester

17.  Huang HM, Lee MC, Chiu WT, Chen CT, Lee SY: Three-dimensional finite element analysis for subdural hematoma. J Trauma 47: 538–544, 1999.  Depreitere B, Van Lierde C, Vander Sloten J, Van Audekercke R, Van Der Perre G, Plets C et al.: Mechanics of acute subdural hematomas resulting from BV rupture. Journal of Neurosurgery 104(6): 950-956, 2006.Journal of Neurosurgery  Löwenhielm P: Strain tolerance of the vv. cerebri sup. (BVs) calculated from head-on collision tests with cadavers. Z Rechtsmedizin 75:131–144, 1974.  Gennarelli TA, Thibault LE: Biomechanics of acute subdural hematoma. J Trauma 22:680–686, 1982.  Lee MC, Ueno K, Melvin JW: Finite element analysis of traumatic subdural hematoma, in Proceedings of the 31st Stapp Car Crash Conference. New York, NY, Society of Automotive Engineers, 1987, pp 67- 77.

18.  Lee MC, Haut RC: Insensitivity of tensile failure properties of human BVs to strain rate: implication in biomechanics of subdural hematoma. J Biomech 22(6-7): 537-42, 1989.  Forbes JA, Withrow TJ: Biomechanics of Subdural Hemorrhage in American Football. Vanderbilt University, 2010

19.  To learn more about Southern Impact Research Center, please visit:  http://www.youtube.com/watch?v=hwA-hiFu4Xw http://www.youtube.com/watch?v=hwA-hiFu4Xw  http://www.soimpact.com/ http://www.soimpact.com/