Coupling Vibration Research of a Turbine Blade-Disc System with Symmetric-Acyclic Structure

The blade-disc in a turbine is characterized by symmetric-acyclic opening structure on the disc body. Four different numerical models with 3-D finite element method were established in the present investigation. The wave propagation technique was employed and the modal analysis of the blade disc was performed. The modal and vibration characteristics of different models in the same rotational speeds were compared in consideration of non-linear coupling/interactions between blade and disc. The results indicate that in the modal analysis of symmetric-acyclic blade-disc system, the openings structure has low impact on the low-order mode frequency. Thus, cyclic symmetric model without the opening structure can help to get general frequency forecast to improve the analysis efficiency.