Mechanical and Thermal Dissipation Analysis of Aluminum in Quasi-Isentropic Compression

To study the pressure-specific volume (p-v) reference line and equation of state from the stress-strain curve of material at high pressure, the viscous dissipation due to loading strain rate and thermal dissipation due to irreversible heat conduction in quasi-isentropic compression experiment (ICE) were discussed and analyzed.A backward integration and forward integration method was used to analyze the data in laser driving and magnetic pressure driving ICE with different strain rates.For viscous dissipation, the sound speed, stress-strain curve, temperature and entropy production during loading were obtained, and the relations between high strain rate and these physical quantities were discussed.For thermal dissipation, through the calculation of the thermal conduction and SCG constitutive model, the variation of temperature and the corresponding yield strength, shear module and sound speed were presented.The results show that:in the laser driving ICE with a high strain rate of 10⁸ s^-1), the temperature variation caused by high strain rate is about 180 K, and the entropy production due to heat conduction is about 250 J/(kg·K); and in the magnetic pressure driving with a relatively low strain rate of 10⁵ s^-1, the entropy production is less than 8 J/(kg·K).