改性双基推进剂高低应变率下压缩特性试验研究

摘要

在室温20℃下,利用分离式霍普金森压杆(SHPB)和材料万能试验机进行了某改性双基推进剂高低应变率下压缩试验,并对SHPB试验数据有效性进行了检验,获得了1.1 ×10-4～4×103 s-1应变率范围内的真实应力-应变曲线.试验结果表明:改性双基推进剂具有明显的应变率相关性.低应变率下,真实应力-应变曲线表现为初始弹性段、屈服及应变强化段和急剧下降阶段,最后表现为试件沿45° ～55°斜面发生破坏,且破坏应力和破坏应变均随着应变率增加而增加;高应变率下,真实应力-应变曲线的应变强化阶段消失,表现为应变软化效应.改性双基推进剂的初始弹性模量和屈服应力均随着应变率的增加而增加,且动态相比准静态下增加更加显著.屈服应力为应变率对数的双线性关系,且高应变率下比低应变率下表现出更显著的应变率敏感性.%The compressive experiments from low to high strain rates have been performed on the material test machine and the split Hopkinson pressure bar(SHPB)apparatus at room temperature of 20 ℃.The availability of SHPB experimental data is examined,and the true stress-strain curves are obtained in the strain rate range from 1.1 × 10-4 s-1 to 4 × 103 s-1.The results show that the modified double base propellant behaves significant strain rate dependence.At low strain rate,the true stress-strain curves show initial elastic stage,yield and strain strengthening stage,and descend stage,in which the specimen fractures along the slope of 45° ～ 55°,and the failure stress and failure strain increase with the strain rate.At high strain rate,the true stress-strain curve shows the effect of strain softening instead of strain strengthening.The initial modulus of elasticity and yield stress of modified double base propellant increases with the strain rate,what's more,they increase substantially at high strain rates compared with those in quasi-static.The relationship between yield strength and logarithm of strain rate is bilinear,which shows more strain rate sensitiveness at high strain rate than at low strain rate.