基于微CT技术的丁羟推进剂脱湿定量表征方法研究

To quantitatively describe dewetting evolutionary process of HTPB propellant during uniaxial tension, a new dumbbell-shaped specimen was designed, which took into account both macro-mechanical properties testing and micro-CT scanning of meso-structure. The law of the average gray value and average porosity of HTPB propellant changed with tensile strain were obtained by in-situ micro-CT scanning tests. The results indicate that with the increase of tensile strain the average gray value of HTPB propellant decreased gradually due to the dual effects of dewetting damage and tensile deformation. The decline rate showed a trend of first increasing, then decreasing and then increasing. The average porosity underwent four stages:a small increase due to initial pore expansion, a sudden increase due to new dewetting damage, a steady increase due to progressive dewetting, and a sudden increase due to crack penetration induced by dewetting damage. It can be seen that the average gray value and porosity are closely related to the meso-structure and macroscopic mechanical properties of HTPB propellant, which can be used for quantitative characterization of its dewetting damage. Comparing with gray value, porosity statistics is more suitable for quantitative characterization of the evolutionary process of the formation and development of dewetting damage of HTPB propellant.