Development of Physiologically Based Injury Criteria for Behind Armor Blunt Trauma


Dr. Robert Salzar of the University of Virginia

US Army Aeromedical Laboratory
Medical College of Wisconsin
Wayne State University
The protective aspect of current body armor is assessed through the ability to stop the penetration of a high-speed projectile if backface deformation does not exceed 44mm.  The resulting back face deformation of body armor from a ballistic impact is assessed through various means with the primary measure being the deformation left in a clay substrate.  However, the criticality of these impacts should be assessed on the location-dependent risk of severe injury and not of only the depth of penetration into the body.  Understanding the region-specific risk of behind armor blunt trauma on morbidity and mortality will lead to the most optimized body armor design. 
Tests using a physiological model are being performed to determine the relationships between ballistic input parameters and organ damage for blunt behind armor trauma.  These tests are being performed across different areas of the thorax hypothesizing that these regions all have unique tolerance to blunt injuries.  The hypothesis, therefore, is that body armor design can be optimized for minimum weight if the probability for injury is known. 
The objectives of this study are to develop thoracoabdominal region-specific injury criteria resulting from energy/momentum transferred from the armor while successfully defeating ballistic threats. We are conducting tests with whole body PMHS that are representative of BABT events with back-face deformation inputs, gather biomechanical data, compare injuries to military epidemiology, and identify injury mechanisms. We are characterizing the acuteness of the injuries by conducting tests with PMHS and cadaver porcine and determining the biomechanical and physiological responses of live porcine specimens leading to functional incapacitation in matched-pair scenarios. Tests with different physiologic endpoints (time of euthanasia), candidate metrics (e.g., acceleration), injury severities, impact regions targeted to the heart, lungs, liver, ribcage, spine, and kidney are being conducted and analyzed for scaling from the animal to human and obtain region- and severity-specific injury response corridors via parametric statistical survival analysis with outcomes ranging from fatality to different levels of functional capacity, appropriate for military missions that include emerging threats. 
We anticipate a panel workshop or symposium session of five (5) to six (6) speakers comprised of members of the University-research consortium: 
  • Joe McEntire of the U.S. Army Aeromedical Laboratory, ( 
  • Dr. Narayan Yoganandan of the Medical College of Wisconsin ( 
  • Dr. Dale Bass of Wayne State University ( 
  • Dr. Robert Salzar of the University of Virginia ( 
  • Up to 2 more to be determined 
The intended audience are those interested in the design optimization of new body armor based on physiological injury which includes military, medical, industry, and academia persons.