Experimental study of the coupling parameters influencing the terminal effects of thoracic blunt ballistic impacts

• The impulse transmitted during the impact reflects the interaction with the thoracic wall.
• Ballistic impacts of three less-lethal projectiles were analyzed on the isolated swine thoracic wall.
• The thoracic wall is weakened after the first rib fracture.
• The impact severity is related to the projectile momentum which remains after the fracture.
• Experimental methods and results enable to relate the projectiles parameters to the thoracic wall response.

The objective of the study is to better understand how blunt projectile ballistic parameters and material properties influence the events leading to injuries. The present work focuses on lateral thoracic impacts and follows an experimental approach.The projectiles are made with a soft foam nose assembled with a rigid rear plastic part.The dynamic properties of the foams were first determined using the Split Hopkinson Pressure Bar (SHPB) system. The impact forces on a rigid wall were then measured to provide reference load data. Lastly, shots were made on isolated thoraxes of porcine cadavers to investigate the response in the vicinity of the impact (wall displacements, rib accelerations and strains, rib fractures). Results show that the severity of the response appears to be mainly correlated with the impulse and with the pre-impact momentum.