High-temperature loading techniques in large-diameter SHPB experiment and its application

To study the dynamic mechanical properties of material at high temperatures, a new high-temperature split Hopkinson pressure bar (SHPB) system was proposed by combining a self-developed temperature-controlling system and an ordinary 100-mm-diameter SHPB system. The ANSYS software was used to analyze the interface heat transfer phenomenon and its influences on the experimental results. The reliability of the experimental technique proposed was demonstrated. And the experimental technique proposed was utilized to investigate the dynamic mechanical properties of concrete at high temperatures. The results show that for the high temperature impact tests on heat-inertia materials such as concrete using the large-diameter SHPB made of alloy steels, the critical value of cold contact time (CCT) is 1.00 s, and the CCT for the experimental technique proposed does not exceed 0.50 s, the experimental technique proposed is credible; and that at invariable loading rate with temperature increasing gradually from normal temperature to 1 000 ℃, the dynamic stress-strain curves of concrete exhibit gradually plasticity properties, the dynamic compressive strength first rises, then falls, and the dynamic peak strain rises constantly.