Modal Analysis of Bleed Air System based on NASTRAN

摘要

Based on the analysis of structure composition, material properties, operating conditions of bleed air system, a finite element model is developed and the natural frequencies and vibration modes are obtained by NASTRAN. The results show that the first ten natural frequencies comparatively dense, each order natural frequency in operating state are lower than the corresponding frequency in non-operating state. The deformations are mainly concentrated in the APU pipe and the two branches arranged with concentrated mass components, and the maximum deformation positions under the two states are different in the same order. This work can assist in design of civil-aircraft bleed air system and similar high temperature and high pressure duct system.