Bladed Disk Reduction for Transient Loading in Blade Tip Rubs and Foreign Object Ingestion

Abstract

Abstract. Nominal bladed disk models are designed as cyclically symmetric structures that can be analyzed using single-sector models to reduce the computational expense. This type of analysis is effective for many structural analyses including generating Campbell diagrams and analyzing the response to engine order excitations. However, the response to transient asymmetric excitation (e.g., due to blade tip rubs or foreign object ingestion) cannot currently be analyzed efficiently. In this work, a new methodology is presented that constructs reduced-order models using only sector-level models and calculations that can be used to compute the time-resolved dynamics of active nodes chosen during the reduction. The methodology keeps the active nodes in the physical coordinate system, while modally reducing the rest of the system. This allows for easy coupling between the dynamics of the active nodes and any modeling that could be involved in determining time-dependent forcing vectors, like an abradable liner wear model in the specific case of blade tip rubs. The presented model is validated for four different forced response solutions representing realistic forcing cases for both blade tip rubs and foreign object ingestion events, showing high levels of agreement between the proposed method’s solutions and full finite element solutions obtained from commercially available finite element solvers. The presented method allowed the forced response solutions to be completed two to three orders of magnitude faster than the full finite element solutions, for the academic bladed disk studied, with greater speed increases expected for larger industrial models.