NUMERICAL SIMULATION ON DYNAMIC COMPRESSIVE BEHAVIOR OF ULTRA-HIGH TOUGHNESS CEMENTITIOUS-COMPOSITES

Investigates the dynamic compressive behavior of PVA fiber reinforced ultra-high toughness cementitious-composites (PVA-UHTCC) using Split Hopkinson Pressure Bar (SHPB) test based on HJC constitutive model. Firstly, 21 parameters of HJC model are determined and the numerical simulation is verified. Then dynamic compressive stress-strain curves under 5 different strain rates are obtained for analyzing the strain-rate effects on Dynamic Increase Factor (DIF). The failure modes of specimens under different strain rates are also researched. The results show that with the increase of strain rate, DIF increases and the strain-hardening dominated behavior will transform into a strain-softening dominated behavior. Besides, PVA-UHTCC shows an obvious different strain-rate sensitivity in the different range of strain rates. Thusly, a functional expression between DIF and lgε is proposed. Compared with Steel Fiber Reinforced Cementitious Composites (SFRCC) and normal concrete, PVA-UHTCC has a lower strain-rate sensitivity. Finally, the crack propagation mechanism and failure modes are observed at LS-DYNA software to furtherly understand the dynamic compressive behavior of PVA-UHTCC.