Study on dynamic energy dissipation mechanism and damage characteristics of high-temperature marble

To investigate the effect of high temperature on the energy characteristics of marble, ANSYS/LS-DYNA was used to carry out dynamic compression simulation tests on marble with six temperature gradients at five impact velocities to analyze the mechanical properties of marble under high-temperature dynamic loading and the temperature effect on energy evolution, and to explore the energy criterion for strength failure of high-temperature marble from the perspective of energy dissipation. The results show that the Holmquist-Johnson-Cook (HJC) constitutive model can reasonably and effectively simulate the dynamic damage process of marble under different temperatures. With the increase in temperature, the dynamic peak strength and dynamic elastic modulus of marble exhibit a quadratic negative correlation with temperature, the dynamic peak strain exhibits a quadratic positive correlation with temperature, and the damage morphology is changed from X-type to conjugate shear damage. The increase in temperature reduces the energy storage capacity of the marble specimen to a certain extent, while the effect of high temperature on the energy dissipation capacity of marble is transformed from a facilitating effect to an inhibiting effect with 600 ℃ as the cut-off point. When the temperature reaches 600 ℃, the peak strength is significantly reduced, the ductility of the marble increases, crushing damage is presented, and the dissipated strain energy reaches the maximum value. 600 ℃ can be used as the threshold temperature for the brittle-delayed transformation of the marble. Based on the characteristics of the energy evolution process, the point of a steep increase in dissipated strain energy is regarded as a precursor information point of the precursor of overall instability and damage of marble. The inflection point at which the growth rate of the elastic energy consumption ratio first appears is defined according to the curve of the stress-elastic energy consumption ratio-strain relationship as the energy criterion of the strength failure of marble.