Experimental and finite element analysis of the generation mechanism of high impulse noise overpressure (caused by a recoilless weapon) at the bottom of the ear

Abstract

The intense impulse noise may damage the soldiers’ hearing organs during a weapon's firing. It is essential to find out the generation mechanism of the overpressure at the bottom of the ear. The experiments of measuring the overpressure at the bottom of the ear were conducted through a rotating human head model at a recoilless weapon firing platform. The results showed that the overpressure peak at the bottom of the ear decreases with the increasing incident angle. A simulation of the test condition was developed based on the plane shock wave method. The finite element model was verified reasonably compared to the test results. The Friedlander wave propagating to the ear canal was implemented at different incident angles. The generation of the overpressure at the bottom of the ear was analyzed. According to the pressure nephograms, the impulse noise stagnated at the bottom of the ear, so the overpressure was the total pressure of impulse noise. Two parts of impulse noise entered the canal successively due to the influence of the pinna. The overpressure and Mach number at the entrance of the ear canal both decreased with increasing incident angles, resulting in impulse noise superimposed at the bottom of the ear. Investigating the generation of overpressure at the bottom of the ear under varying incident angles may have important reference value for analyzing and preventing auditory organ damage caused by impulse noise.