NEPE推进剂拉伸破坏过程实验研究

Experimental Study on Tensile Damage Process of NEPE Propellant

为研究NEPE推进剂在拉伸载荷作用下的破坏情况,利用扫描电镜对其在拉伸载荷作用下的细观形貌变化进行了原位观察。结果表明:NEPE推进剂在静态拉伸应力作用下首先在大填充颗粒处出现界面脱粘,形成微裂纹,同时粘合剂被拉成丝状。然后微裂纹沿着附近的大填充颗粒处进行扩展,形成宏观裂纹,同时伴随着粘合剂的断裂,并最终导致NEPE推进剂出现整体断裂。本文进一步利用有限元方法对不同大小填充颗粒在拉伸作用下的受力情况进行了分析,结果表明在相同应变下,大颗粒粘结界面处的应力明显大于小颗粒粘结界面处的应力。因此,认为NEPE推进剂在静态拉伸过程中的主要破坏模式为大填充颗粒处的粘结界面破坏。

In order to study the damage process of NEPE propellant during tensile condition ,the micro-structure of NEPE sample was observed by in situ SEM. The resuhs show that the interphase dewetting and crack are first founded around big grains. And the binder is pulled into silk shape. Then the crack in NEPE propellant extends through the big grains and collects into macro-crack. On the other hand, the stress distribution in grain-binder unit was also analyzed by finite element method. The analysis shows that the effective stress in big grain-binder unit is much greater than that of small grain-binder unit. So, the main damage model of NEPE propellant during tensile process is interphase damage between big grain and binder.