High-Fidelity Nonlinear Forced Response Analysis of Aero-Engine Turbine Blades With Root Friction Contact

In aero-engines, turbines drive compressors and fans by extracting energy from the combusted hot air. For the next generation ultra-high bypass ratio engines, the turbine blades are among the most critical components due to the harsh operating environments. A turbine blade consists of a streamlined aerofoil and the blade root. The root is designed in such a way that it can be inserted into a similar yet marginally bigger slot on the disk. The most common root designs include dovetail and firtree roots. Under normal operation, the blade root is loaded against the slot in the disc by centrifugal forces due to rotation. During operation, blade vibration can lead to microslip in the roots, which generates additional frictional damping and leads to a nonlinear dynamic response. The complex geometry of the blade and its support require high-fidelity finite element analysis to capture the linear dynamic response accurately and detailed frictional interface models to capture the nonlinear response. Therefore, to predict correct amplitude under dynamic loads, friction should be included together with a detailed blade structural dynamics model. This work presents a framework that can combine detailed finite element models with friction models so that a realistic nonlinear dynamic response of the blade can be obtained at representative amplitudes.