Behind Amor Blunt Trauma Lung and Liver Strains From Indenter Loading Via Finite Element Modeling.

To determine behind armor blunt trauma (BABT) injury criteria, experiments have been conducted by launching blunt projectiles at live swine at velocities up to 65 meters per second (m/s) using one type of indenter design. To ensure the generalizability of the developed injury criteria, additional tests with different indenter designs are needed. The objectives of this study were to evaluate the kinematics and injury parameters from two indenter designs using human body finite element modeling. The simulation matrix consisted of chord and cylindrical shape indenter designs with two different masses of 150 and 230 grams. They were used to impact the liver and lung regions at velocities of 30 and 60 m/s using a human body model. Rib and lung strains from lung impacts and rib strain and liver strain energy densities (SED) from liver impacts were used to evaluate the design variables of mass and shape. Both designs played a role in skeletal and organ injury parameters. Analysis revealed an increased susceptibility for skeletal and organ traumas with the high mass indenter during high velocity impacts. The cylindrical indenter may be protective for organ injuries due to the larger area of loading on the ribcage compared to the chord indenter. Results from the chord indenter may serve as a conservative estimate of injury criteria.