Rig and Engine Validation of the Nonlinear Forced Response Analysis Performed by the Tool OrAgL

Abstract

Since the first nonlinear forced response validation of frictionally coupled bladed disks, more than 20 years have passed, and numerous incremental modeling and simulation refinements were proposed. With the present work, we intend to assess how much we have improved since then. To this end, we present findings of an exhaustive validation campaign designed to systematically validate the nonlinear vibration prediction for the different friction joints at blade roots, interlocked shrouds and under-platform dampers. An original approach for the identification of crucial contact properties is developed. By using the dynamic Lagrangian contact formulation and a refined spatial contact discretization, it is demonstrated that the delicate identification of contact stiffness properties can be circumvented. The friction coefficient is measured in a separate test, and determined as unique function of temperature, preload, wear state. Rotating rig and engine measurements are compared against simulations with the tool OrAgL, developed jointly by the Leibniz Universität Hannover and the University of Stuttgart, in which state-of-the-art component mode synthesis (CMS) and harmonic balance methods (HBMs) are implemented.