Scaling the response of armor steel subjected to blast loading

The influence of the strain-rate effect of steel and the mechanical effect of explosive shock load are both key problems to achieving the similarity scaling of a steel plate structure under blast loading. In this research, the scaling of the dynamic response of strain-rate sensitive armor steel subjected to air blast loading was studied further. First, the specific impulse was defined, and the influence of the strain-rate and the geometric scaling ratio on the specific impulse correction factor was analyzed with dimensional analysis. Then, a real air explosion test was carried out to study the response of a full-size armor steel plate during a blast, and the Johnson-Cook constitutive parameters of the armor steel material were obtained using split Hopkinson pressure bar experimental technology, with which the accurate scaling base mode was established. Furthermore, by employing the correction factors of the specific impulse and the total impulse calculated by empirical equations, two correction methods were proven: I-correcting the stand-off distance and II-correcting the charge mass. Then, the relationships between the specific impulse, the total impulse, the stand-off distance and the charge mass are discussed, based on which the explosion load boundary corresponding to the geometric scaling coefficient was determined. The results showed that the prediction of the corrected scaled model was in good agreement with the experimental results, and both methods could achieve the scaling of the response of the armor steel plate subjected to blast loading.