基于动态故障树分析的民用飞机辅助动力装置系统安全性评估

在民用航空工业领域,传统的故障树分析方法广泛运用于系统安全性评估。然而,包含系统/子系统运行的时序阐述以及备份、冗余表达在内的动态特性不能通过传统故障树呈现。另一方面,民用飞机辅助动力装置(APU)经常作为一个冗余系统运作,因而其行为可以通过运用动态故障树进行适当的描述。所以APU的这种特性激发了动态故障树分析在APU系统安全性评估上应用的关注。首先介绍了两种动态门(优先与门和冷备件门),其定量计算通过施用马尔可夫模型来呈现;然后分别通过传统故障树以及动态故障树分析了APU系统安全性评估的两个典型案例;最后进行了两种故障树分析(FTA)的比较,其结果显示出通过合理的应用,动态故障树(DFTA)方法达到了对于真实情况来说相当高的精度,并且对指数分布函数施用二阶近似后,其运算成本也是可以接受的。

Safety Assessment of Auxiliary Power Unit(APU) System for Civil Aircraft Based on Dynamic Fault Tree Analysis(DFTA)

Traditional fault tree analysis method is widely used for system safety assessment in civil aviation industry , but dynamic characteristics of systems/ subsystems, including operational sequencing interpretation, spare and redundancy expression cannot be represented by traditional fault trees. On the other hand, civil aircraft auxiliary power unit(APU) often operates as a redundant system and its behavior can be described by using dynamic fault tree appropriately. As a result, the interest of DFTA application is focused on APU system safety assessment. In this paper, two kinds of dynamic gates (PAND and CSP) were introduced firstly. Their quantitative calculations were presented by applying Markov model. Then two typical cases with auxiliary power unit (APU) system safety assessment were analyzed by traditional fault tree and dynamic fault tree respectively. Finally the comparison between two kinds of Fault Tree Analysis (FTA) was provided and the result indicates that Dynamic Fault Tree Analysis (DFTA) method based on proper application reaches remarkable accuracy ,and the calculation cost is acceptable when second-order approximation of exponential distribution function is applied.