基于有限元法的输液管路稳定性可靠性研究

为分析航空发动机空间管路系统的稳定性可靠性问题，提出了一种采用有限元法和蒙特卡洛法相结合的分析方法。方法中采用有限元法建立空间管路系统流固耦合模型，定义了稳定性失稳的极限状态函数，采用蒙特卡洛法进行稳定性可靠度计算。典型工程算例的计算结果表明:给定流体流速的均值，发散失稳的概率随流体流速的变异系数可能增加或减小；给定流体流速的变异系数，随流体流速均值的增加，管路系统稳定性极限状态函数由服从连续概率密度函数变为服从混合概率密度函数。研究结果对于航空发动机输液管路的稳定性可靠性设计和评估具有参考价值。 

Research on stability reliability of pipe conveying fluid based on finite element method

For analysis of the stability reliability of spatial aeroengine pipe system, a probabilistic reliability method based on finite element method (FEM) and Monte Carlo method (MCM) was proposed. A fluid structure coupling model of the pipe system was established with FEM. A limit state function of stability reliability was presented on the basis of analysis of natural frequency. The stability reliability was calculated using MCM. The analysis results of typical pipe system showed that: for a given mean flow velocity, as the variation of flow velocity increased, the divergence instability probability may increase or decrease; for a given variation of flow velocity, the probability density function of limit state function changed to the mixed probability density function from the continuous probability density function as the mean value of flow velocity increased. The result is valuable for stability reliability design and analysis of pipe system conveying fluid.