Abstract
Over the past years the use of Operational Modal Analysis (OMA) for Structural health monitoring has become more and more widespread. Such a methodology would also be relevant to wind farm owners that want to monitor the integrity of their turbines’ foundations.
However, harmonic components, originating from the rotor and periodic aerodynamic forces, are present within the measured vibrations. The harmonics violate the set of assumptions of common OMA techniques and as a result, these techniques potentially fail. This paper explores the different techniques presented in the literature to handle these harmonics. The techniques are first presented and later applied on data of an offshore wind turbine in the Belgian North Sea.
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References
Heylen W, Sas P (2006) Modal analysis theory and testing. Katholieke Universteit Leuven, Departement Werktuigkunde
Magalhães F, Cunha Á (2011) Explaining operational modal analysis with data from an arch bridge. Mech Syst Signal Process 25(5):1431–1450
Manzato S, White JR, LeBlanc B, Peeters B, Janssens K (2014) Advanced identification techniques for operational wind turbine data. In: Topics in modal analysis. Springer, New York
Weijtjens W, Verbelen T, De Sitter G, Devriendt C, et al. (2014) Data normalization for foundation shm of an offshore wind turbine: a real-life case study. In: EWSHM-7th European Workshop on Structural Health Monitoring
Manzato S, Devriendt C, Weijtjens W, Di Lorenzo E, Peeters B, Guillaume P (2014) Removing the influence of rotor harmonics for improved monitoring of offshore wind turbines. In: Dynamics of civil structures, vol 4. Springer, New York, pp 299–312
Peeters B, Cornelis B, Janssens K, Van der Auweraer H (2007) Removing disturbing harmonics in operational modal analysis. In: Proceedings of International Operational Modal Analysis Conference
Hermans L, Van der Auweraer H, Hatami A, Cooper E, Uhl T, Lisowski W, Wasilak A (1999) In-flight modal testing and analysis of a helicopter. In: Society for experimental mechanics, inc, 17 th international modal analysis conference, vol 1, pp 80–86
Qi K, He Z, Li Z, Zi Y, Chen X (2008) Vibration based operational modal analysis of rotor systems. Measurement 41(7):810–816
Weijtjens W, Shirzadeh R, De Sitter G, Devriendt C (2014) Classifying resonant frequencies and damping values of an offshore wind turbine on a monopile foundation for different operational conditions. In: Proceedings of EWEA
Devriendt C, De Sitter G, Vanlanduit S, Guillaume P (2009) Operational modal analysis in the presence of harmonic excitations by the use of transmissibility measurements. Mech Syst Signal Process 23(3):621–635
Weijtjens W, De Sitter G, Devriendt C, Guillaume P (2014) Operational modal parameter estimation of mimo systems using transmissibility functions. Automatica 50(2):559–564
Motte K (2014) Operational modal analysis in the presence of harmonic excitations: a review. Master’s thesis, Vrije Universiteit Brussel
Jacobsen NJ (2006) Separating structural modes and harmonic components in operational modal analysis. In: Proceedings IMAC XXIV Conference
Brincker R, Zhang L, Andersen P (2000) Modal identification from ambient responses using frequency domain decomposition. In: Proceedings of 18th International Modal Analysis Conference, pp 625–630
Pintelon R, Peeters B, Guillaume P (2008) Continuous-time operational modal analysis in the presence of harmonic disturbances. Mech Syst Signal Process 22(5):1017–1035
Randall RB, Hee J (1982) Cepstrum analysis. Wirel World 88:77–80
Randall RB, Peeters B, Antoni J, Manzato S (2012) New cepstral methods of signal pre-processing for operational modal analysis. In: Proceedings of ISMA
Mohanty P, Rixen DJ (2004) Operational modal analysis in the presence of harmonic excitation. J Sound Vib 270(1):93–109
James GH, Carne TG, Lauffer JP (1995) The natural excitation technique (next) for modal parameter extraction from operating structures. Int J Anal Exp Modal Anal 10(4):260–277
Guillaume P, Verboven P, Vanlanduit S, Van Der Auweraer H, Peeters B (2003) A poly-reference implementation of the least-squares complex frequency-domain estimator. In: Proceedings of IMAC, vol 21, pp 183–192
Mohanty P, Rixen DJ (2006) Modified era method for operational modal analysis in the presence of harmonic excitations. Mech Syst Signal Process 20(1):114–130
Mohanty P, Rixen DJ (2004) A modified ibrahim time domain algorithm for operational modal analysis including harmonic excitation. J Sound Vib 275(1):375–390
Devriendt C, El-Kafafy M, De Sitter G, Guillaume P (2012) Estimating damping of an offshore wind turbine using an overspeed stop and ambient excitation. In: Proceedings of 15th International Conference on Experimental Mechanics
Acknowledgements
The financial support of the Institute for the Promotion of Innovation by Science and Technology in Flanders (IWT) and the Research Council (OZR) of Vrije Universiteit Brussel (VUB) are gratefully acknowledged.
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Motte, K., Weijtjens, W., Devriendt, C., Guillaume, P. (2015). Operational Modal Analysis in the Presence of Harmonic Excitations: A Review. In: Caicedo, J., Pakzad, S. (eds) Dynamics of Civil Structures, Volume 2. Conference Proceedings of the Society for Experimental Mechanics Series. Springer, Cham. https://doi.org/10.1007/978-3-319-15248-6_40
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DOI: https://doi.org/10.1007/978-3-319-15248-6_40
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