Validation of New Numerical Analysis Tools for Nonlinear Forced Response in Anisotropy-Mistuned Bladed Disks With Friction Joints

Abstract

New numerical tools ContaDyn and InterDyn have been developed at University of Sussex for the analysis of nonlinear forced response for tuned and anisotropy mistuned bladed disks with friction contact interfaces. The tools offer capabilities for calculating the nonlinear forced response and its sensitivity with respect to the anisotropy orientation variation of single crystal blades in tuned and mistuned bladed disk assemblies. The calculation method is based on the high-accuracy reduction techniques and the multi-harmonic balance method. A comprehensive validation campaign has been done to validate these numerical capabilities. The calculated nonlinear forced responses are compared with the experimental values obtained for different bladed disk configurations and excitations. The friction contact interfaces at blade roots, blade shrouds and under-platform dampers are considered. For the validation, the measurement data, that were obtained earlier at MTU Aero Engines AG using their rotating test rig, are used. The vibratory measurements were carried out with the contact-less expected time-of-arrival method allowing capturing the vibratory amplitudes for all blades in a mistuned bladed disk assembly. The nonlinear forced response for tuned and anisotropy mis-tuned bladed disks have been calculated for four different resonances and compared with the minimum, maximum and mean values of the measured amplitudes. Moreover, the individual blade forced response levels obtained from measurements and calculations are compared with the maximum amplitude distributions in the mistuned bladed disks. Parametric studies considering the number of harmonics used in the multiharmonic representation of periodic response, the number of mode shapes, the contact stiffness and friction coefficient values have been performed.