Experimental study of the effect of an air shock wave on a human head simulator

BACKGROUND: To date, several methods have been developed to study the effect of air shock waves on biological objects and their simulators; however, existing approaches are largely limited to recording only a narrow range of parameters of air shock waves. This limitation significantly hinders reliable assessment of damage to biological objects and does not allow adequate determination of the effectiveness of reducing shock-wave exposure by personal armor protection. AIM: To develop and substantiate an experimental approach to assessing the protective properties of armored helmets against air shock wave exposure using a ballistic/biomechanical head simulator and a conical shock tube with a 14° apex angle to solve applied problems in the design of armored helmets. METHODS: A conical shock tube with a 14° apex angle was used to generate shock waves. A ballistic/biomechanical head simulator was used to record data during the interaction with the shock wave. The experiments evaluated the change in the shape of the air shock wave front, the maximum pressure, and the duration and impulse of the compression and rarefaction phases, depending on the type of helmet worn on the ballistic/biomechanical head simulator. RESULTS: The interaction of a shock wave with a ballistic/biomechanical head simulator causes a compression wave in the latter without a clear front, with a smooth increase in pressure. This phenomenon is related to the inertial characteristics of the elastic shell and the liquid contained within it. In a ballistic/biomechanical head simulator protected by an armored helmet, the duration of the compression phase increases, the level of excess pressure decreases, and the rate of pressure rise decreases. The degree of shock wave intensity reduction depends on the design features of both the helmet dome and the helmet liner. CONCLUSION: The data obtained during the experimental studies have significant practical value, as they allow improving the structure of personal armor protection equipment, in particular—armored helmets, to increase their protective characteristics and reduce the likelihood of injury from exposure to a shock wave.