Dynamic mechanical properties and constitutive model of red sandstone under different loading rates and high temperatures

Dynamic compression experiments were conducted on red sandstone utilizing a split Hopkinson pressure bar (SHPB) to study the loading rate and high temperatures on their mechanically deformed properties and ultimate failure modes, and to analyze the correlation between the strain rate, temperature, peak strength, and ultimate failure modes. The results show that the mass decreases with the increase of treatment temperature, and the pattern of the stress -strain curves is not impacted by the increase of impact velocity. Under a fixed temperature, the higher the impact velocity, the higher the strain rate and dynamical compression strength, indicating a strain rate hardening effect for red sandstone. With an increasing treatment temperature, the strain rate gradually increases when the impact loading remains unchanged, suggesting a rise in the deformability of red sandstone under high-temperature environment. Raise in both impact velocity and treatment temperature leads to an intensification of the damage features of the red sandstone. Similarly, higher strain rates lead to the intensification of the final damage mode of red sandstone regardless of the change in treatment temperature. Moreover, a dynamic damage constitutive model that considers the impacts of strain rate and temperature is proposed based on experimental results.