不同状态HTPB推进剂动态冲击损伤研究

针对HTPB推进剂长期服役中面临动态冲击的风险,以未老化、热老化和湿热老化三种不同状态HTPB推进剂为研究对象,研究动态冲击条件下HTPB推进剂损伤情况,采用细观检测设备(SEM,CT),以分形维数相结合的方式,定性和定量分析了损伤情况。研究结果表明,未老化和热老化HTPB推进剂动态冲击后,内部的损伤主要表现为颗粒穿晶断裂和破裂、基体与颗粒的界面损伤、基体撕裂、孔隙率增大等,经分析表明冲击时应力集中区易于在AP颗粒内部和颗粒/基体界面产生。而湿热老化HTPB推进剂在动态损伤后,表现为基体与颗粒的界面"脱湿"、基体撕裂和少量的颗粒断裂,冲击时应力集中区主要在颗粒/基体界面产生。采用分形维数对冲击后的损伤情况进行定量表达,损伤情况的严重程度由高到低依次是热老化、未老化和湿热老化,温度越低应变率越高,损伤越严重,同等实验条件下湿热老化的分形维数比未老化的情况减小了0.13%～4.82%,而热老化后的分形维数比未老化的情况提高了11.8%～15.0%。

Research on dynamic impact damage of HTPB propellant under different states

Abstract: In view of the risk of dynamic impact in the long-term service of HTPB propellant, this paper takes HTPB propellant of unaged, thermal aged and humid-thermal aged conditions as the research object, and studies the damage of HTPB propellant under dynamic impact, using microscopic inspection equipment(SEM, CT) and fractal dimension to acquire a combination of qualitative and quantitative analysis of the damage situation. The results show that after the dynamic impact of unaged and thermal aged HTPB propellant, the internal damage mainly manifests as grain transgranular fracture, interface damage between matrix and particles, matrix tearing, porosity increasing, etc. The stress concentration zone is easily generated inside the AP particles and at the particle/matrix interface. However, the humid-thermal aged HTPB propellant after dynamic impact, the internal damage presents as "dewetting" at the interface between the matrix and particles, matrix tearing and minor particles fracture, and the stress concentration area is mainly generated at the particle/matrix interface during impact. Fractal dimension is used to quantitatively express the damage situation after impact. The overall trend of damage severity from high to low is thermal aged, unaged and humid-thermal aged conditions. The lower the temperature, the higher the strain rate and the more serious the damage.