中文摘要：

以典型的单元推进剂液体火箭模型为例,通过Hurwitz稳定性判据导出POGO振动稳定的充分必要条件,在此基础上深入研究阻尼比等参数对POGO振动稳定性的影响机理。研究发现,当结构阻尼比小于推进系统阻尼比时,结构阻尼比对于POGO振动稳定性的影响是单调上升的,此时临界阻尼比法是适用的;当结构阻尼比大于推进系统阻尼比时,结构阻尼比对于POGO振动稳定性的影响则是非单调和复杂的,增加结构阻尼比,可能提高系统稳定性,也可能降低系统稳定性,此时临界阻尼比法已不适用。相同的结论适用于推进系统阻尼比。本文还进一步指出结构与推进系统的耦合强度是POGO振动稳定性的决定因素。

英文摘要：

Effects of damping ratio on propulsion-structure coupled system in liquid rockets are further studied based on necessary and sufficient conditions of POGO stability derived from the typical monopropellant liquid rocket model according to Hurwitz stability criterion. It is found that the critical damping ratio method is clearly applicable only to the case that the damping ratio of structure is less than one of propulsion system because the effect of structural damping ratio on POGO stability is monotonically increasing. However,the critical damping ratio method is not always applicable to other cases because the effect of structural damping ratio on POGO stability is non-monotonic and complex. In other words,the POGO stability may be enhanced or be weakened with the increase of structural damping ratio. Same conclusions are derived for effects of damping ratio of propulsion system. Finally,the coupled strength of propulsion-structure interaction is emphasized to be a decisive factor of affecting POGO vibration stability.