Energy dissipation law and damage constitutive relationship of low-temperature fine sandstone under impact loading

To investigate the energy dissipation law and damage constitutive relationship of low-temperature fine sandstone under impact loading, impact compression tests were conducted on Jurassic Cretaceous fine sandstone at different temperatures by using the SHPB test system, and the stress-strain curves of fine sandstone at different temperatures were recorded. The relationship between the dynamic peak stress and temperature and the energy dissipation law of the sample in the test was analyzed, and the relationship between the fractal dimension of fragmentation and temperature was explored by introducing the fractal dimension, D. A constitutive model of the statistical damage model for dynamic strength damage of fine sandstone based on the Weibull statistical distribution and D-P failure criterion was established. The results show that the stress-strain curve of fine sandstone under impact loading can be divided into four stages: compaction, linear deformation, plastic deformation and rapid unloading. The dynamic peak stress increases with decreasing temperature. The fractal dimension of fine sandstone after crushing under impact loading gradually increases with decreasing temperature, and the correlation coefficient between the fractal dimension and temperature of the sample is 0.936, demonstrating a good exponential relationship. Because the microelement strength of the experimental fine sandstone obeys the Weibull statistical distribution and the parameters F ₀ and m are calibrated, a dynamic strength statistical damage constitutive model of the fine sandstone at different temperatures is established, compared with the experimental results, verifying the rationality of the model.