Research On Dynamic Tensile Properties Of Typical Wound Ballistic Target Materials

In the field of trauma ballistics,to study the injury effect of human body under impact load(bullet,blunt instrument,explosion shock wave,etc.),typical trauma ballistic target materials similar to human soft tissue are generally used for impact loading,such as skin,fat,muscle and other soft tissue materials of animals.The study of the dynamic mechanical properties of the trauma ballistic target material is helpful to better analyze the injury mechanism of the impact load on human body.Because of the softness and slippery of the soft biological materials,it is very difficult to test their dynamic mechanical properties,especially in dynamic tensile testing.In this paper,based on the experiment,a set of testing method of dynamic mechanical properties of biological soft materials based on the direct stretching SHTB experimental technology was proposed,and the dynamic tensile tests of the skin of pig chest and the muscle of pig hind leg were carried out with this method,and finally the dynamic mechanical properties of typical trauma ballistic target materials were obtained.In this paper,firstly,a SHTB experimental device for dynamic tensile test of biological soft materials was studied,that was,using hollow aluminum rod as transmission rod,and cooperating with semi conducting strain gauge technology to realize the measurement of weak signal in transmission rod;the effective tensile length of the sample was determined by the improved tubular clamp holding the sample.Then a data processing software of Hopkinson bar experiment was developed.The software adopted interactive graphic interface,which could complete the task of data processing conveniently and quickly.The dynamic tensile tests of pig skin and muscle were carried out with the improved SHTB experimental device,and the stressstrain curves of pig skin and muscle at high strain rate were obtained with the developed software.The experimental results show that the stress-strain curves of soft biomaterials have obvious nonlinear characteristics and strain rate sensitivity.At last,Ogden model and a Maxwell unit viscoelastic constitutive model were used to fit the experimental results,and the strain ratedependent constitutive model of pig skin and muscle was obtained.