Modal Strain Energy Based Damage Detection Applied to a Full Scale Composite Helicopter Blade

Abstract:

The use of composites in the aircraft industry has generated a great need for structural health monitoring and damage detection systems, to allow for safer use of complex materials. Such is the case with helicopter blades - these components nowadays are mostly composed of carbon fiber or glass fiber reinforced plastics laminates, epoxy and honeycomb filled core structures. The use of composite materials on the main rotor blade also allows for more complex and efficient shapes to be designed, but at the same time, their use requires an additional effort when it comes to structural monitoring, since damage can occur and go unnoticed. This work presents experimental results for structural health monitoring method based on strain energy. The test subject is a full-scale composite helicopter main rotor blade, which is a highly flexible, slender beam that can display unusual dynamic behavior with orthotropic behavior. This damage detection method is based on the modal strain properties, and a damage detection index is used to identify and quantify damage. A test setup was built to carry out an experimental modal analysis on the main rotor blade. For that purpose, a total of 55 uniaxial accelerometers were used on the helicopter blade to measure the displacement modes of the structure. To compute the strain modes from the displacement modes, central differences approximation is used. Damage is introduced on the blade by attaching a small mass to two different locations. Experimental results show the possibility of locating damage in this case.

• Periodical: Key Engineering Materials (Volumes 569-570)
• Pages: 457-464
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.569-570.457
• Online since: July 2013
• Authors: Fabio Luis Marques dos Santos, Bart Peeters, Herman van der Auweraer, Luiz Carlos Sandoval Góes
• Keywords: Helicopter Blade, Strain Energy Damage Index, Structural Health Monitoring (SHM), Vibration Based Damage Detection

References

[1] A. Gessow and G.C. Myers. Aerodynamics of the Helicopter. F. Ungar Publishing Company, (1967).

[2] L. Nicolais. Composite Materials: A Vision for the Future. Springer Verlag, (2011).

[3] C. Boller, F.K. CHANG, and Y. Fujino. Encyclopedia of structural health monitoring, volume 67. Wiley, (2009).

[4] D. Balageas, C.P. Fritzen, A. Guemes, and Inc NetLibrary. Structural health monitoring, volume 493. Wiley Online Library, (2006).

[5] J. Maeck, B. Peeters, and G.D. Roeck. Damage identification on the z24 bridge using vibration monitoring. Smart materials and structures, 10: 512, (2001).

DOI: 10.1088/0964-1726/10/3/313

[6] A. Patterson-Hine, W. Hindson, D. Sanderfer, S. Deb, and C. Domagala. A model-based health monitoring and diagnostic system for the uh-60 helicopter. In Annual Forum Proceedings – American Helicopter, volume 57, pages 1552–1564. American Helicopter Society, Inc, (2001).

[7] E. Reynders and G. De Roeck. A local flexibility method for vibration based damage localization and quantification. Journal of sound and vibration, 329(12): 2367–2383, (2010).

DOI: 10.1016/j.jsv.2009.04.026

[8] TH Ooijevaar, R. Loendersloot, LL Warnet, A. De Boer, and R. Akkerman. Vibration based structural health monitoring of a composite tbeam. Composite Structures, 92(9): 2007–2015, (2010).

DOI: 10.1016/j.compstruct.2009.12.007

[9] N. Stubbs, J.T. Kim, and CR Farrar. Field verification of a nondestructive damage localization and severity estimation algorithm. In Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, volume 2460, page 210, (1995).

[10] TA Duffey, SW Doebling, CR Farrar, WE Baker, WH Rhee, and S.W. Doebling. Vibration-based damage identification in structures exhibiting axial and torsional response. Transactions of the ASME-L-Journal of Vibration and Acoustics, 123(1): 84–91, (2001).

DOI: 10.1115/1.1320445

[11] R. Loendersloot, TH Ooijevaar, L. Warnet, A. Boer, and R. Akkerman. Vibration based structural health monitoring and the modal strain energy damage index algorithm applied to a composite t-beam. Vibration and Structural Acoustics Analysis, pages 121–150, (2011).

DOI: 10.1007/978-94-007-1703-9_6

[12] S.E.M. Mourad. Proposed technique for identifying damage location using change in mode shapes parameters. Technical Report 30, Scientific Bulletin of Faculty of Engineering, Ain Shams University, (2007).

[13] M.N. Helfrick, P. Pingle, C. Niezreck, and P. Avitabile. Using full-filed vibration measurement techniques for damage detection. In Proceedings of the IMAC-XXVII, (2009).

[14] C.R. Farrar, P.J. Cornwell, S.W. Doebling, and M.B. Prime. Structural health monitoring studies of the alamosa canyon and i-40 bridges. Technical report, Los Alamos National Lab., NM (US), (2000).

DOI: 10.2172/766805

[15] H. Hu, B.T. Wang, C.H. Lee, and J.S. Su. Damage detection of surface cracks in composite laminates using modal analysis and strain energy method. Composite structures, 74(4): 399–405, (2006).

DOI: 10.1016/j.compstruct.2005.04.020