PHYSICAL SENSE OF THE PLASTIC MODULUS OF METALLIC MATERIALS AT HIGH STRAIN-RATES

摘要

In this paper, impact experiments in nitrogen alloyed austenitic steel (high-N steel) and 685 steel were carried out with the split Hopkinson pressure bar (SHPB) apparatus. It can be found from the experiments that the plastic modulus and the strain-rate sensitivity exponent are two main factors of holding together materials dynamic steadiness at high strain-rates. In particular, the magnitude of plastic modulus indicated the ability with transferring stress-wave load in aspect of physical nature. The greater this value, the greater is absorbency of projectile dynamical energy for target material. This conclusion has been proved by fitting Johnson-Cook model parameters and correlative numerical calculation and microcosmic analysis. Continuing above thoughts, the estimation of terminal ballistics performance of target material using Johnson damage number and hardening damage number will be applied in engineering.