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Integrally bladed rotors dynamic properties are known to be particularly sensitive to small geometric discrepancies due to the machining process or in-service wear. In this context, it is straightforward that setting up accurate numerical models which take into account real mistuning patterns is a key issue in the prediction of forced response amplitudes under operating conditions. The present study focuses on an experimental bladed disk. Due to strong inter-blade coupling, the geometric mistuning is supposed to result in severe mode localization for the studied bladed disk, thus emphasizing the need of a realistic, predictive finite-element model. This paper describes the procedure which leads to the development and validation of a high-fidelity FE model for a realistic bladed disk, based on coordinate measurements by means of fringe projection. After giving an overview of the coordinate measurement and model building for the studied bladed disk, the comparison of cantilevered-blade and full disk calculated eigenfrequencies to individual blade and full disk in quasi-vacuum measurements are presented.

This paper proposes a mixed hardware and software solution to impose different controlled dynamic load patterns to a bladed disk using non-intrusive acoustic excitation. The test bench is coupled to an autonomous measurement system consisting of an infrared Laser Doppler Vibrometer (LDV) placed on a robotic arm. The development of the test bench is described from the definition of the requirements up to the calibration of the different components (acoustic excitation devices, power amplifiers, LDV positioning, etc.). The relation between the supplied voltage and the resulting pressure acting on the blade is also assessed. The main application of the developed test bench consists in the imposition of Standing or Traveling Waves Excitation in order to appropriate a given nodal diameter content and experimentally study the response to typical excitation pattern encountered when integrated on motor. Another application consists in the experimental mistuning measurement through modal analysis and the use of the Inverse Component Mode Mistuning method.

This paper proposes an original approach to the reduced-order modelling of integrally bladed disks. It is proposed to build a reduction basis which is independent from the rotational speed, from only one modal, cyclic-symmetry calculation performed at rest, and a few static computations. Based on previous works, a polynomial expansion is used which leads to a parametric approximation of the stiffness matrix for the entire operating range. Furthermore, the Kirsch Combined Approximation (KCA) method is used for building the final reduction basis. This method is based on successive approximations of the negative binomial expansion applied to the reanalysis eigenproblem. After giving a general overview of the main theoretical aspects, the paper focuses on the reanalysis problem based on the combined approximations method. Finally, the application of the extended reduction method to the case of a real bladed disk is presented. It is shown that the use of combined approximations provides a very accurate estimation of a Campbell diagram, and allows substantial computational time savings.

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