Accession Number : ADA520964


Title :   Rapid Quantification of Energy Absorption and Dissipation Metrics for PPE Padding Materials


Descriptive Note : Final technical rept. 22 Apr-22 Oct 2009


Corporate Author : TEXAS UNIV AT SAN ANTONIO


Personal Author(s) : Connolly, Thomas J ; Cruz, Gabriel


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a520964.pdf


Report Date : 22 Jan 2010


Pagination or Media Count : 26


Abstract : The use of energy-absorbing/dissipating materials in personnel helmets to reduce the effects of blast pressures can have unanticipated adverse effects. The presence and/or configuration of these materials can focus energy in such a way that it can cause unforeseen traumatic brain injuries. The purpose of this research is to develop a innovative modeling and simulation approach for rapidly quantifying metrics that characterize the energy absorption/dissipation capacity of candidate materials to be used in retrofitted helmets and other personnel protective equipment (PPE.) Metrics such as the saturation point of the material with respect to maximum blast loads, and the ratio of the total blast energy to the energy that is transmitted to the victim, are used to rate two candidate materials. Quantification of these metrics is accomplished using dynamic modeling and simulation technique, facilitated by impedance-based bond graphs. These models include novel elements whose constitutive laws are defined by fractional derivatives, which capture frequency-dependent viscoelastic and viscoinertial properties of energy absorbing/dissipating materials. Input forces caused by blast pressures, determined from computational fluid dynamics (CFD) analysis and simulation of common blast sources encountered in current conflicts, are used to generate the externally applied force inputs for material modeling simulations.


Descriptors :   *TRAUMATIC SHOCK , *HELMETS , *ENERGY ABSORBERS , *PROTECTIVE EQUIPMENT , BRAIN , MODELS , DYNAMICS , MATERIALS , ENERGY , RATES , DISSIPATION , COMPUTATIONAL FLUID DYNAMICS , PRESSURE , ADVERSE CONDITIONS , BLAST LOADS , CASUALTIES , WOUNDS AND INJURIES , PERSONNEL , BLAST , SYMPOSIA , RATIOS , METHODOLOGY , SIMULATION , SOURCES


Subject Categories : Safety Engineering
      Protective Equipment


Distribution Statement : APPROVED FOR PUBLIC RELEASE