为研究典型丁羟推进剂在低压冲击作用下的点火机理,基于热点理论,建立了该型推进剂落锤试验的三维仿真模型,采用有限元计算方法和三项式点火增长反应速率模型对丁羟推进剂的落锤试验进行数值模拟,分析整个撞击过程中推进剂的点火反应和动态力学响应。研究结果表明,在整个撞击过程中,由于受冲击后推进剂径向变形,剪切应力集中分布在推进剂上、下表面边缘区域,摩擦应力产生局部热量集中形成热点,引起推进剂发生点火及爆炸。计算得到了,在落高为75 cm时,10 kg落锤撞击丁羟推进剂的起爆阈值为540.2 MPa²·s。

In order to study the ignition mechanism of typical HTPB propellant under low pressure impact, a three-dimensional simulation model of drop-weight test of HTPB propellant was established based on hot spot theory. The drop-weight test of HTPB propellant was numerically simulated by finite element method and trinomial ignition growth reaction rate model, and the ignition response and dynamic mechanical response of HTPB propellant during the whole impact process were analyzed.The results show that during the whole impact process, due to the radial deformation of the propellant after the impact, the shear stress is concentrated on the edge of the upper and lower surface of the propellant, and the friction stress produces local heat concentration to form a hot spot, which causes the propellant to ignite and explode.It is calculated that when the falling height is 75 cm, the initiation threshold of 10 kg drop hammer impact HTPB propellant is 540.2 MPa²·s.