Presentation: Tangential interpolation for the operational modal analysis ofaeronautical structures

Tangential interpolation for the operational modal analysis of aeronautical structures Gabriele Dessena1, Marco Civera2, and Oscar E. BonillaManrique3 1Department of Aerospace Engineering, Universidad Carlos III de Madrid, Leganés, Madrid, Spain 2Department of Structural, Geotechnical and Building Engineering, Politecnico di Torino, Turin, Italy 3Electronic Technology Department, Universidad Carlos III de Madrid, Leganés, Madrid, Spain 16th October 2025 Madrid, Spain 15th European Aerospace Science Network Conference [email protected] Tangential interpolation for aerostructures OMA Outline 1. Contributions 2. Background 3. Motivation 4. Operational modal analysis 5. The Loewner framework 6. Natural Excitation Technique 7. NExT-LF 8. eXperimental Beards 2 Wing 9. eXperimental Beards 2 Wing Spar 10. Experimental results 11. Conclusions 16th October 2025 Dessena et al – 15th EASN 2025 2 Tangential interpolation for aerostructures OMA Contributions •Extend the Loewner framework (LF) to operational modal analysis •Apply the method to a benchmark aeronautical structure •Validate the results against benchmark and standard methods 16th October 2025 Dessena et al – 15th EASN 2025 3 Tangential interpolation for aerostructures OMA Background •Modal parameters extraction is important in aeronautics •Finite element model tuning •Aeroelastic phenomena characterisation •In other domains, such as Civil engineering, they are also used for damage detection •Recently, an accurate and efficient method has been introduced for experimental modal analysis •The Loewner framework (LF) •Robust to noise •Accurate in large systems and closely spaced modes •However, sometimes input is unknown/impossible to apply •Operational modal analysis (OMA) 16th October 2025 Dessena et al – 15th EASN 2025 4 Tangential interpolation for aerostructures OMA Motivation •Modal parameter identification can be cumbersome for •Large systems •Closely spaced modes •This can be even harder when the test input is unknown •Their direct comparison is cumbersome for large systems •An efficient modal parameter identification frequency domain method addresses the above •Loewner framework (LF) •An extension to output-only data is sought to exploit its robustness 16th October 2025 Dessena et al – 15th EASN 2025 5 Tangential interpolation for aerostructures OMA Operational modal analysis •Output-only modal analysis •Operational modal analysis (OMA) •Same goal as the traditional approach •Extract modal parameters •Sometimes there is a need •Unknown input •Structure too large to be excited •Popular methods include stochastic subspace identification (SSI) and frequency domain decomposition (FDD) 16th October 2025 Dessena et al – 15th EASN 2025 6 Retrieved from1. Credits to kronja2. 1. J. Sinske, Y. Govers, G. Jelicic, R. Buchbach, J. Schwochow, V. Handojo, M. Böswald, and W. Krüger, “Flight testing using fast online aeroelastic identification techniques with DLR research aircraft HALO,” in Proc. IFASD 2017 – Int. Forum on Aeroelasticity and Structural Dynamics, Como, Italy, 2017. 2. https://commons.wikimedia.org/wiki/File:Hardangerbrua_(15028061131).png Tangential interpolation for aerostructures OMA The Loewner Framework •Relies on the Loewner Matrix (𝕃 – 1930s) •From the 80s, Antoulas and coauthor have: •Defined a connection between the 𝕃 and rational approximation •Resulted in the application of 𝕃 as a rational interpolant •Model order reduction (MOR) in the frequency domain •Applications to MOR •Electrical circuits •Unsteady Aerodynamics 16th October 2025 Dessena et al – 15th EASN 2025 7 1. A. C. Ionita, "System Identification," Antonio Cosmin Ionita – Rice University, [Online]. Available: https://aci.rice.edu/system-identification/. [Accessed: May 19, 2025]. 2. Quero, D., Vuillemin, P., & Poussot-Vassal, C. (2019). A Generalized State-Space Aeroservoelastic Model Based on Tangential Interpolation. Aerospace, 6(1), 9. MIMO circuit LF ROM, from1. Theodersen’s function fit from2. Tangential interpolation for aerostructures OMA The Loewner Framework (Cont’d) •How does it work? •Interpolation technique •Exploiting data partitioning for tangential interpolation •The idea: •Given a linear time-invariant system •𝐄𝑑 𝑑𝑡𝐱(𝑡) = 𝐀𝐱(𝑡) + 𝐁𝐮(𝑡); 𝐲(𝑡) = 𝐂𝐱(𝑡) + 𝐃𝐮(𝑡) •A Laplace transfer function can be fitted •𝐇𝑠 =𝐂s𝐄−𝐀−1𝐁 •𝐃=𝟎 (no feedthrough) •Modal parameters extracted from eigenanalysis of the system matrices •Limitation: Frequency response function needed (input and output data) 16th October 2025 Dessena et al – 15th EASN 2025 8 Tangential interpolation for aerostructures OMA Natural Excitation Technique •Or maybe not… •Natural Excitation Technique – NExT •Cross-correlation between output signals •One or more reference channels •𝑅𝑥𝑦 replicates an equivalent impulse response function (IRF) •First applied to wind turbines in the 80s •Traditionally paired with the Eigensystem Realization Algorithm (NExT-ERA) •Main assumption: •Stationarity – Always true for ambient •But it can be relaxed 𝑅𝑥𝑦 𝜏 =lim 𝑇→∞1𝑇න0𝑇𝑥𝑡𝑦𝑡+𝜏d𝑡 16th October 2025 Dessena et al – 15th EASN 2025 9 Credits to Hans Hillewaert1. Tangential interpolation for aerostructures OMA Conclusion •An OMA variant of the LF is employed on an aeronautically relevant system •Good correlation to benchmark results and standard methods is achieved •NExT-LF offers enhanced stability when compared to other NExT alternatives, like NExTERA •Future work: Extend NExT-LF to automatic modal analysis, using data clustering algorithms 16th October 2025 Dessena et al – 15th EASN 2025 16 Tangential interpolation for aerostructures OMA Acknowledgements Multiannual agreement with UC3M - IA_aCTRl-CM-UC3M project 16th October 2025 Dessena et al – 15th EASN 2025 17 CEAS EuroGNC conference 2026 hosted at Universidad Carlos III de Madrid May 5th – 7th 2026 Organizing committee Local Organizing Committee Andrés Marcos, UC3M, Conference Chair Rafael Vázquez, Universidad de Sevilla, Conf. Deputy Chair Diego Navarro-Tapia, UC3M, Local Arrangements Chair Gabriele Dessena, UC3M, International Arrangements Chair CEAS GNC Technical Committee Nicolas Fezans, DLR, Chair of the Committee Raziye Tekin, Roketsan, Co-chair of the Committee TC member roster, see conference webpage Conference Venue The EuroGNC 2026 conference will be hosted at the Universidad Carlos III de Madrid (UC3M). The conference venue is located in the city center, at the Campus Puerta de Toledo. Numerous famous monuments, museums, and parks can be reached in less than 20-30 min on foot, with metro/bus stations also available just outside the conference venue. Madrid is a vibrant city known for its rich cultural heritage, lively atmosphere and warm hospitality. Madrid generally enjoys pleasant weather in May. Attendees can also look forward to experiencing the city’s renowned tapas scene. Topics: •Control Theory, Analysis and Design •Applications of GNC •Intelligent Control/AI in Aeronautics/Astronautics •Aerospace Robotics •Novel Navigation, Estimation and Tracking methods •Sensor Systems for GNC •Flight Mechanics, Dynamics, and Simulation •Modelling for Aerospace Systems •Flight Testing and Experimental Results Key dates September 30th, 2025 Full Paper Submission Deadline Nov/Dec, 2025 Author notification February 20th, 2026 Final Paper Submission Deadline Jan/Feb, 2026 End of Early-Bird Registration May 5th-7th, 2026 EuroGNC Conference in Madrid Please enquire if you have a full paper ready / or ready by the 30th of October Opportunity for students to present their theses in a dedicated poster session Deadline: Feb 2026 Organising committee Organising Committee Erasmo Carrera, Politecnico di Torino, General Chair Yongming Liu, Arizona State University, Technical Chair Ibrahim Guven, Virginia Commonwealth University, Technical Vice-Chair Tracks: •Structures •Structural dynamics •Materials Key dates November 3rd, 2025 Abstract Deadline November 12th, 2025 Author notification Structural dynamics track 1. Aero-, Servo-, Thermo-Elasticity of Aircraft, Rotorcraft and Spacecraft 2. Rotordynamics 3. Aeroacoustics and Vibroacoustics 4. Nonlinear Dynamics and Flexible Multibody Dynamics 5. Dynamic Loads, Wave Propagations, Response, Vibration, Control, and Alleviation of Aerospace Structures and Vehicles 6. Computational Methods and Modelling 7. Experimental Studies in Structural Dynamics 8. Machine Learning in Structural Dynamics and Aeroelasticity 9. Model Uncertainties and Uncertainty Quantification in Structural Dynamics 10. General Topics of Structural Dynamics of Aircraft, Rotorcraft, and Spacecraft Structures Invitation to submit to •Nonlinear Dynamics and Flexible Multibody Dynamics •Experimental Studies in Structural Dynamics Topic organiser: Gabriele Dessena, UC3M Tangential interpolation for aerostructures OMA Thank you for your attention! Main bibliography •G. Dessena, M. Civera, A. Yousefi, and C. Surace, ‘NExT‐LF: A Novel Operational Modal Analysis Method via Tangential Interpolation’, Int Journal of Mech Sys Dyn, vol. 5, no. 3, pp. 401–414, May 2025, doi: 10.1002/msd2.70016. •G. Dessena, M. Civera, L. Zanotti Fragonara, D. I. Ignatyev, and J. F. Whidborne, ‘A Loewner-Based System Identification and Structural Health Monitoring Approach for Mechanical Systems’, Structural Control and Health Monitoring, vol. 2023, pp. 1–22, Apr. 2023, doi: 10.1155/2023/1891062. •G. Dessena, D. I. Ignatyev, J. F. Whidborne, A. Pontillo, and L. Zanotti Fragonara, ‘Ground Vibration Testing of a Flexible Wing: A Benchmark and Case Study’, Aerospace, vol. 9, no. 8, p. 438, Aug. 2022, doi: 10.3390/aerospace9080438. 16th October 2025 Dessena et al – 15th EASN 2025 20 Presentation download ResearchGate profile