Controlling high frequency vibrations of aircraft engines
The VibSEA project is a response to the need of aircraft engine manufacturers to extend the field of observation and control of the vibratory behavior of designed systems. In pre-dimensioning or design phase, the numerical methods commonly used show limitations when the analysis focuses on high frequencies. VibSEA proposes to implement a systematic method to predict these vibratory behaviors up to 10kHz, based on an approach hybridizing finite elements analysis (FEA) and statistical energy analysis (SEA).
Medium and high frequency methods based on the statistical representation of energy
As the frequency of analysis increases, the vibratory phenomena size down and are localized on homogeneous zones (subsystems) of the structure between which energy transfers occur according to the excitations. Traditional finite element analysis (FEA) require in practice a very refined discretization (requesting excessively large computing resources) associated with dispersion management. Whereas the statistical energy analysis (SEA) enables a description of these subsystems based on the average vibratory energy response to a given excitation. This energy is transmitted via connections between subsystems through the overall system studied.
Established a few decades ago and implemented at ESI in the VA One software, SEA is a predictive method that has won its spurs throughout various industry sectors, including aeronautics.
Recently, innovative approaches enabled the implementation of a hybrid method coupling SEA subsystems via FEA substructures in order to simulate medium frequencies. Indeed, the FEA method allows to better represent the more rigid parts of the model at these frequencies than the SEA. This hybrid FEA-SEA method has been implemented in the VA One software used for the VibSEA project to combine the contributions of each approach and to study the system on a wide frequency spectrum.
The modeling choices are qualified, along with a test campaign carried out on real parts. The simulations are implemented in order to establish a systematic approach differing from the empirical practices which require an increased experience of the energy methods. This methodological approach is a strong component of the VibSEA project in terms of objectives.
A project initiated by a first-tier supplier and funded by the European Union
ESI and CETIM have joined forces to carry out this project supported by CleanSky, an integral part of the European Horizon 2020 research program under grant agreement no. 831893.
The VibSEA project will last three years (2019 to 2022) and is led by CETIM, which also contributes its technical expertise in experimental characterization, while the simulation part is led by ESI Group.
The prospects of the project are significant for the manufacturer's teams, who will be able to rely on predictive analyses of high-frequency vibrations, conducted on the concepts of the new generations of aircraft engines. To this end, the project initiator is making one of the key components of its propulsion systems available to the collaborators as a study part.
