改性双基推进剂的动态断裂实验研究

为研究改性双基推进剂的动态断裂特性,利用直裂缝平台巴西圆盘试件,运用分离式霍普金森压杆系统对推进剂材料进行冲击实验研究。基于一维应力波理论,通过压杆上应变片测定的信号确定试件所受冲击载荷随时间的变化。采用在试件上贴应变片的方法,用记录的最大信号值确定材料的起裂时刻。在验证实验数据有效性的前提下,获得了此种推进剂材料在不同速率下的起裂韧度。结果表明:动态条件下采用应变片测定推进剂材料起裂时刻的方法是可行和有效的;改性双基推进剂材料起裂韧性具有明显的加载率敏感性,起裂韧性随加载率呈线性增长关系。

Dynamic fracture experiment of modified double-base propellant

In order to study the dynamic fracture properties of modified double-base propellant,the impact test of cracked straight-through flattened Brazilian disc(CSTFBD)specimen was performed with the split Hopkinson pressure bar(SHPB).Based on the one-dimensional stress wave theory,the strain value measured by strain gauges tied on the bars was used to decide the changes of impact load with time. In addition,the critical failure time was determined by detecting the maximum signal value recorded on the strain gauges tied on the specimen. After examining the availability of data,the fracture initiation toughness of the material under different loading rates was obtained. The result suggests that the method of using the strain gauge to determine the initiation time is feasible and effective. Meanwhile,this kind of solid propellant is a significant loading rate material under dynamic condition and its fracture initiation toughness increases linearly with the loading rate.