铝镁贫氧推进剂压缩力学性能及本构模型实验研究

Experimental Research on Compressive Mechanical Properties and Constitutive Model of Aluminum-Magnesium Fuel Rich Propellant

为获得贫氧推进剂在压缩情况下的力学特性,运用单向压缩方法、显微镜及CCD图像传感器技术,研究了铝镁贫氧推进剂在常温下、不同压缩速率时的力学特性,得到其在压缩情况下的应力-应变关系、屈服应力和屈服应变与压缩速率之间的关系以及在压缩过程中推进剂表面形貌的变化.建立了贫氧推进剂压缩情况下的粘弹性本构模型.试验结果表明,贫氧推进剂在压缩情况下应力-应变关系分弹性段、应变软化段、塑性不稳定段和应变强化段;贫氧推进剂力学特性受压缩速率和温度耦合作用的影响,贫氧推进剂的破坏形貌没有明显的压缩速率效应;常温下,贫氧推进剂的屈服应力和屈服应变与压缩速率的自然对数呈线性函数关系;文中建立的粘弹性本构模型与不同应变率下的线粘弹性段试验结果符合较好.

To obtain the mechanical properties of fuel rich propellant under compression,the uniaxial compression method,a microscope and CCD image sensor technology were applied to the research of mechanical properties of aluminum-magnesium fuel rich propellant under room temperature and different compression rates.The stress-strain relationship,the relationship between yield stress and compression rate and the relationship between strain and compression rate were obtained,and surface morphology was observed in the compression process.The viscoelastic constitutive model was also established.The results show that the stress-strain relationship of aluminum-magnesium fuel rich propellant under compression can be divided into elastic stage,strain-softening stage,plastic-unsteady stage and strain hardening stage;the mechanical properties of fuel rich propellant are affected by compression rate and temperature.The damage morphology is almost unaffected by compression rate;the yield stress and yield strain show a linear relation with the natural logarithm of compression rate under room temperature.The theoretical results of viscoelastic constitutive model are in good agreement with experimental results in the linear and viscoelastic range of the stress-strain curve.