A solid-beam hybrid modeling approach for vibration and stress analysis of a casing-multiple pipes system

Abundant achievements have been obtained on single planar pipe dynamics, but the vibration and dynamic stress analysis of complex spatial multi-pipe systems in aero-engines remains a challenge. Therefore, a novel solid-beam hybrid modeling approach is proposed to establish an efficient dynamic model for such a casing-multiple pipes system (C-MPS). The core of this strategy lies in a region-specific modeling of the pipe assembly: pipe segments prone to high dynamic stress are modeled with solid elements to capture local details accurately, while the remaining segments are modeled using Timoshenko beam elements to enhance computational efficiency. The accuracy of the solid-beam coupling approach in predicting pipe stress is verified through static analysis of a cantilevered pipe. Furthermore, the validity of the proposed hybrid model is demonstrated by comparing its numerical predictions with experimental data from modal tests, constant-frequency, and frequency-sweep experiments conducted on a dedicated test rig. This work establishes that the presented hybrid modeling approach provides an efficient and reliable solution for the vibration and, more importantly, the dynamic stress analysis of aero-engine casing-multiple pipes systems.