| With the research and development of the new protective material,the body armor is gradually developing to the aim of lightless and comfort.In operation of individual combat and public security maintenance,the soft body armor has been able to effectively prevent the direct damage of the pistol to the human body.But the impact kinetic energy of the pistol bullet still acts on the human body and causes the so-called impact sag,as a result,the human body will suffer the blunt trauma,which is similar to the damage caused by blunt.This critical blunt trauma may make the human visceral and skeletal under average,even leads to the death of human.At present,the research of blunt trauma is not comprehensive and thorough at home and abroad,most of these research are on blunt sags,and especially the study on the characteristics of the pressure wave in targets is not thorough.Therefore,it is necessary to carry out the corresponding experimental and numerical simulation research on human physiological response.In this paper,the preparation method of a new type of "gelatin-thorax" bionic dummy has been presented.The "gelatin-thorax" bionic dummy prepared can more truly simulate the mechanical response of the human skeleton and the viscera in various impact tests.The"gelatin-thorax" bionic dummy with internal embedded sensors was placed as the body upper trunk target for the test,the multi parameter synchronous test system was established with the high-speed photography,infrared synchronous trigger.This test of various pistol bullet impacting soft body armor covered "gelatin-thorax" upper trunk target was successfully carried out,obtained the internal pressure of the target and acceleration response law,and captured the whole blunt process.The test results showed that when the type 92 9mm lead core pistol bullet was used to shoot the heart of the "gelatin-thorax" upper trunk target,the peak pressure at the heart was 1.440MPa?1.610MPa;when the type 51 7.62mm lead core pistol bullet was used to shoot the heart of the "gelatin-thorax" upper trunk target,the peak pressure at the heart was 1.630MPa;when the 9mm Parabellum bullet was used to shoot the heart of the "gelatin-thorax" upper trunk target,the peak pressure at the heart was 0.590MPa.The test results also showed that the impact pressure wave would decay rapidly when it spread all around in the target.The greater the pressure was,the faster it decayed,the attenuation speed would gradually decrease during the attenuation process,and the target would absorb the energy of the pressure wave.Due to the foam plate's effect of wave absorption,the insertion of foam plate behind the soft body armor could effectively reduce the impact pressure of the blunt damage.In this paper,the numerical simulation of the 360m/s 9mm pistol bullet penetrating into armor covered the human body trunk target was carried out,and the damage situation of the body armor and pistol bullet obtained by the simulation is basically consistent with the damage situation of live-ammunition test.The calculation results show that the shear failure of the body armor happened at the initial stage of the penetration,and the body armor's obstruction on the bullet was poor.So the energy loss of the bullet was small and its speed dropped slowly;with the bullet's thick pier deformation,the tensile deformation happened on the weft-free fabric at the rear part of the body armor.So the impact kinetic energy of the bullet was effectively absorbed and its speed dropped rapidly;when the impact point was the heart,the maximum equivalent stress of the left lung was 0.231 MPa,the maximum equivalent stress of the right lung was 0.363MPa,the maximum equivalent stress of the heart was 0.056MPa.The experimental and numerical simulation carried out by this paper can provide theoretical and methodological support for the analysis and evaluation of blunt injuries,and scientific basis for the improvement of the power of light weapons and the protective performance of the soft body armor. |
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