Investigation of the dynamic compression behavior and energy absorption properties of PMI foam
Due to the low impedance characteristics of PMI foam materials,aluminum rods and semiconductor strain gauges were used to improve the loading and measurement methods for the split Hopkinson pressure bar(SHPB),and the effect of the length of strike bar on the experimental results was analyzed.It is found that the strike bar with a length of 800 mm can ensure the reliability of the experimental results.The dynamic compressive experiments of PMI foam ma-terials with different densities were carried out by using the improved SHPB,and the dynamic stress-strain curves were obtained at strain rates ranging from 2 150-3 500 s-1,and the influence of the density and strain rate on the dynamic me-chanical properties and energy absorption characteristics of PMI foam materials was analyzed.The results show that the platform stress of PMI foam at high strain rate increases significantly with the strain rate.Compared with the results of the quasi-static load case,the platform stress increases by 52.5%,and the dynamic energy absorption efficiency also in-creases with density and strain rate.The PMI foam shows an obvious strain rate sensitivity.Based on the experimental re-sults of the density of 52 kg/m3,75 kg/m3 PMI foam materials,a revised constitutive model equation was developed that incorporates the parameters of density,strain and strain rate.Then,the revised constitutive model was then verified by using experimental data of the density of 110 kg/m3.The results are in good agreement.This work provides a data support for the application of PMI foam materials in the field of safe protection.
万方数据
维普
