基于能量耗散率的NEPE推进剂疲劳损伤分析

Fatigue Damage Evaluation of NEPE Propellant Based on Dissipated Energy

为研究NEPE推进剂在应变加载条件下的疲劳损伤演化,基于循环加载过程中的推进剂耗散能变化,利用能量耗散变化比对推进剂疲劳过程进行分析。通过4个应变幅值进行了单轴拉伸疲劳试验,得到不同应变幅值下NEPE推进剂疲劳寿命,并得到在不同加载周次下的耗散能。结果表明,这种能量法能够以直观的方式解释疲劳损伤过程中损伤的累计,在对数坐标下耗散能变化比的稳定值与疲劳寿命呈明显的线性关系,稳定值随初始加载应变幅值的增大而增加。当加载应变增大时,材料稳定段相邻加载间损伤累计越快,疲劳寿命相对减小,也解释了2次循环加载间损伤发展的原理。

To study the fatigue damage evolution of NEPE propellant in controlled strain fatigue tests ,the ratio of dissipated energy change-approach based on the distribution of dissipated energy was used to analyze the fatigue damage process .According to four strain-amplitudes,the uniaxial drawing fatigue test was conducted .The fatigue life and dissipated energy under different strain-amplitudes were obtained .The result shows that the energy approach can intuitively explain the damage accumulation in the process of fatigue damage.Plotting plateau value of ratio of dissipated-energy and fatigue life behave in a linear relation.The plateau value is highly dependent on the initial loading strain amplitude , and the plateau value increases with the strain amplitude .The accumulative rates of the damage increase with the strain levels for the adjacent loading cycles , but the fatigue life decreases relatively , and the mechanism of damage increasing between the adjacent loading cycles can be explained .