Methods for Assessment of Composite Aerospace Structures
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In this paper results of detection and localization of artificially initiated delaminations in small carbon fibre reinforced polymer (CFRP) and glass fibre reinforced polymers (GFRP) samples were presented. The first method was electromechanical impedance method (EMI). In the research real part of electrical impedance (resistance) was measured. Delamination in CFRP sample caused frequency shift of certain resonance frequencies visible in resistance characteristic. The second method was based on scanning laser vibrometry. It is a noncontact technique that allows to measure vibration of structure excited by piezoelectric transducer. During research standing waves (vibration–based method) and propagating waves (guided waves–based method) were registered for CFRP sample. In the vibration–based method, the frequency shifts of certain resonance frequencies were analyzed. In guided waves-based technique, the interaction of elastic waves with delamination can be seen in the RMS energy map. The third method is based on terahertz spectroscopy. Equipment utilizes an electromagnetic radiation in the terahertz range (0.1–3 THz). During research time signals as well as sets of time signals creating B–scans and C–scans were analysed. The obtained results showed that the THz spectroscopy technique can detect and visualize delamination between the GFRP layers.
KeywordsElectromechanical impedance EMI Laser vibrometry Guided waves Terahertz spectroscopy Composite materials
This research was supported by the project entitled: Non–invasive Methods for Assessment of Physicochemical and Mechanical Degradation (PBS1/B6/8/2012) granted by National Centre for Research and Development in Poland.
The research leading to these results has been partially supported by project funded by Polish National Science Center under the decision no. DEC–2013/11/D/ST8/03355.
- 4.Karpowicz N, Dawes D, Perry MJ, Zhan X–C (2006) Fire damage on carbon fiber materials characterized by THz waves. In: Proceedings of SPIE, p 6212Google Scholar
- 6.Giurgiutiu V (2008) Structural health monitoring with piezoelectric wafer active sensors. Elsevier, pp 747Google Scholar
- 7.Buethe I, Moix–Bonet M, Wierach P, Fritzen C–P (2014) Check of piezoelectric transducers using the electro–mechanical impedance. In: 7th European workshop on structural health monitoring, Nantes, FranceGoogle Scholar
- 8.An Y–K, Kim MK, Sohn H (2012) Airplane hot spot monitoring using integrated impedance and guided wave measurements. Struct Control Health Monit 19(7):592–604Google Scholar
- 9.Na S, Lee KK (2013) A multi–sensing electromechanical impedance method for non–destructive evaluation of metallic structures. Smart Mater Struct 22:095011 (8pp)Google Scholar
- 11.Siebel T, Lilov M (2013) Experimental investigation on improving electromechanical impedance based damage detection by temperature compensation. In: 10th international conference on damage assessment of structures, Dublin, Ireland, July 8–10Google Scholar
- 13.Malinowski PH, Wandowski T, Ostachowicz WM (2014) Characterisation of CFRP adhesive bonds by electromechanical impedance. In: Proceedings of SPIE, p 9064Google Scholar
- 14.Ruzzene M (2007) Frequency–wavenumber domain filtering for improved damage visualization. Smart Mater Struct 16(6)Google Scholar
- 15.Wandowski T, Malinowski P, Ostachowicz W (2013) Guided waves–based damage localization in riveted aircraft panel. In: Proceedings of SPIE, p 8695Google Scholar