Non-direct tensile loading of sheet specimens on a classical split Hopkinson bars apparatus

Impulsive and impact loading are applied on reduced specimens to determine viscoplastic behaviour laws and to fix their strain rate sensitivity on large domains. Conventional tensile testing on sheet specimens raise the problem of the specimen holding mode which generally induces impedance mismatches and perturbs the elastic pulses on Hopkinson bars testing. This paper presents a non-direct tensile testing configuration using a classical Hopkinson bars apparatus. The interest of this configuration is to reduce section arrangements and to keep compression loading capabilities. A test programme is carried out on a low carbon steel alloy at plastic strain rates between 200 and 440 s -1 . Full FE simulations of the testing device have been conducted on the basis of the same testing conditions so as to evaluate the quality of the elastic pulses and to observe local phenomena. Numerical results revealed deviations in stress and strain rate values regarding comparable experimental databases. Hypotheses are made and investigated by the authors to identify the origin of the problem. Further investigations will be found out for a better understanding of experimental set-up;