| The conventional SHPB technique is improved by using a pulse shaper. Pulse shapers technique is used to modify the incident wave and decrease the effect of wave dispersion to ensure stress equilibrium and homogeneous deformation in specimen, and furthermore a constant strain rate is attained during the loading history. The lasting time of acceleration pulse is enhanced to numerable MSEL, which is more close to actual loading.The curves of stress value, velocity and the over-loading acceleration-time in the initiator are attained after the experimentations were simulated by the FEA software Ansys/Ls-dyna.The following is concluded conformably from the result of experiment and the numerical simulation:(1) The smaller cross section of cylindrical shaper, the more loading wave is close to sine wave, while the ladder shaper can get appreciatively triangular wave. Both of them can expand the rising time of the wave.(2) The Hopkinson experiment with pulse shaper can modify obviously the loading wave and obtain a loading condition of a near constant strain rate by getting a slippery incident wave and decreasing the effect of the wave dispersion to eliminate high-frequency surge.(3) It costs more than 100 μS with shaper than 20 μS without shaper out and away before the stress arrives the maximum, and the acceleration pulse lasts much longer, which is more close to the reality loading condition of initiator.(4) Experiment results show that the compressive stress-strain curves of initiator have the "three regions" character than that without shaper, namely elastic region, collapse region and densification region. The strain-dependence is also shown strongly.(5) It is proved that the SHPB experiment with pulse shaping is more close to the reality condition of initiator at over-loading, and provides bases for constituting new evaluation methods of security and reliability to initiator.
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