Dynamic Mechanical Properties And Constitutive Model Of Dummy Skin Materials

Dummy skin materials are often used to replace human skin in many complex environments.In these service processes,it is inevitable to withstand the dynamic impact load.In order to make the dummy skin material can truly reflect the mechanical response of human skin when it subjected to dynamic impact loads.It is necessary to understand the dynamic mechanical properties of the dummy's skin and establish an accurate constitutive model.In this paper,the dummy skin material is subjected to quasi-static loading test,including low strain rate uniaxial compression test,compression relaxation test and compression creep test.The test results show that the dummy skin material has obvious hyperelastic and viscoelastic properties and has a certain strain rate sensitivity.According to the mechanical properties of the dummy skin material under quasi-static loading,the characterization for the mechanical behavior of the dummy skin material by common hyperelastic model and viscoelastic model is investigated.It is found that these commonly used hyperelastic and viscoelastic models can describe well the mechanical behavior of the dummy skin material.But the model parameters under different strain rates are different,making the model not general,which is not conducive to application.To this end,this paper develops a modified form of ZWT model and rate-dependent visco-hyperelastic model.By comparing with the experimental results,both models can better describe the mechanical behavior of the dummy skin material under low strain rate.According to the mechanical properties of the dummy skin material,based on the principle of Hopkinson pressure bar?SHPB?test,a set of SHPB test platform suitable for testing its dynamic mechanical behavior was established.The stress-strain curves for strain rates of 1510s^-1,2260 s^-1 and 3000 s^-1 were obtained.The test results show that the ability of the skin material to resist deformation under high strain rate is significantly higher than that under low strain rate resistance to deformation.And there are obvious nonlinear characteristics and strain rate correlation.In order to obtain the constitutive model of the dummy skin material under high strain rate,the ZWT model and the visco-hyperelastic model were used to characterize the mechanical behavior.Among them,the original ZWT model can describe the mechanical behavior of the dummy skin material under high strain rate loading more accurately,but the corresponding model parameters are different under each strain rate,making the model not general,and it needs to be modified.In the development of the visco-hyperelastic model,a relaxation test was used to determine the order of the relaxation function for the viscoelastic part.The modified ZWT model and the visco-hyperelastic model can realize the mechanical behavior characterization of the dummy skin material under high strain rate loading,which can provide corresponding model and data support for the application of dummy skin material under dynamic impact load.