Sun Zhengwei, Xu Jinsheng, Zhou Changsheng, Chen Xiong, Guo Zongtao, Song Qixuan
School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing, 210094, Jiangsu, China.
Sci Rep. 2024 Nov 18;14(1):28452. doi: 10.1038/s41598-024-78669-9.
The study of mechanical properties and failure mechanism of propellants under impact loads is crucial for analyzing structural integrity of propellant charges. An experimental investigation was conducted on NEPE propellant using a separated Hopkinson pressure bar to conduct high strain rate uniaxial impact tests. Deformation and failure processes of the propellant under impact conditions were recorded with a high-speed camera. The microscopic failure forms of the propellants were observed using a scanning electron microscope and an optical microscope. Stress-strain curves and high-speed images revealed that the damage behavior and failure mechanism of NEPE propellants are significantly influenced by strain rate. As the strain rate increases, there is a notable increase in the deformation degree of the propellant specimens, with a more pronounced shear effect. This leads to an earlier occurrence of failure and a more severe degree of failure. The predominant failure forms observed in NEPE propellants include transgranular failure, matrix tearing, and cavity merging. A nonlinear visco-hyperelastic constitutive model with damage at high strain rates was established to provide a precise account of the mechanical response of NEPE propellant under high strain rates.
研究推进剂在冲击载荷下的力学性能和失效机理对于分析推进剂装药的结构完整性至关重要。利用分离式霍普金森压杆对NEPE推进剂进行了实验研究，以开展高应变率单轴冲击试验。用高速摄像机记录了推进剂在冲击条件下的变形和失效过程。使用扫描电子显微镜和光学显微镜观察推进剂的微观失效形式。应力-应变曲线和高速图像表明，NEPE推进剂的损伤行为和失效机理受应变率的影响显著。随着应变率的增加，推进剂试样的变形程度显著增大，剪切效应更为明显。这导致失效更早发生且失效程度更严重。在NEPE推进剂中观察到的主要失效形式包括穿晶断裂、基体撕裂和孔洞合并。建立了高应变率下含损伤的非线性粘弹性本构模型，以精确描述NEPE推进剂在高应变率下的力学响应。
