不同拉伸速率下改性双基推进剂的力学特性

为研究改性双基推进剂力学性能的率相关性，开展了不同速率下改性双基推进剂单轴拉伸力学性能试验，并利用扫描电镜对拉伸断面的形貌进行了观察，分析了拉伸速率对推进剂力学性能以及断面形貌的影响，以及不同拉伸速率下的破坏模式。结果表明：随拉伸速率的增加，推进剂应力-应变曲线逐渐出现应变强化现象，且现象越来越明显；推进剂的初始模量、强度随拉伸速率的增大呈现上升趋势；推进剂的断裂伸长率随拉伸速率的增大，呈现先上升后下降的趋势，在0.24%·s-1应变速率附近达到极值；随拉伸速率的增大，推进剂的破坏模式分别表现为颗粒“脱湿”、基体断裂、颗粒断裂。

Mechanical Properties of Modified Double-Base Propellant under Different Tensile Rates

To study the mechanical properties of modified double-base propellant, the uniaxisl tensile tests of modified double-base propellant have been conducted over a range of tensile rates. And the morphology of the tensile section was observed by scanning electron microscopy(SEM). The influence of the tensile rate on the mechanical properties and the fracture morphology of the propellants was analyzed, as well as the failure modes at different tensile rates. The results show that with the increase of the tensile rate, the strain strengthening phenomenon gradually appears in the stress-strain curve of propellant, and the phenomenon becomes more and more obvious. The initial modulus and strength of the propellant increase with the increase of the tensile rate. The breaking elongation of propellant rises first and then decrease with the increase of the tensile rate, the extreme value is reached near the strain rate of 0.24%·s-1. With the increase of the tensile rate, the failure modes of propellant are respectively dehumidification, matrix fracture and particle fracture.