Methodological aspects of testing brittle materials using the split Hopkinson bar technique

This paper presents the features of a method for determining the dynamic properties of brittle materials using the split Hopkinson bar technique on mortar as an example. Experiments were conducted both with and without a loading pulse shaper, a deformable copper disc (pad) placed on the impacted end of the input bar. Experimental data from the experiments without the pad were processed with and without dispersion correction based on a direct solution of the Pochhammer–Chree frequency equation of pulses in the measuring bars. There were compared both the deformation graphs and mechanical characteristics of the tested material for three variants of the split Hopkinson pressure bar experiments: with and without a loading pulse shaper, and with the dispersion correction procedure for pulses in the measuring bars. The phenomena observed during these experimental schemes and the processing of obtained data are described and discussed; further, the effect of the nature of the load increase is revealed.