Investigation to Local Defect Resonance for Non-Destructive Testing of Composites

• Main Authors: Joost Segers, Mathias Kersemans, Erik Verboven, Saeid Hedayatrasa, Javier Calderon, Wim Van Paepegem
• Format: Article
• Language: English
• Published: MDPI AG 2018-05-01
• Series: Proceedings
• Subjects: local defect resonance (LDR); Frequency Band Data (FBD); non-destructive testing (NDT); composite materials; Laser Doppler Vibrometry (LDV)
• Online Access: http://www.mdpi.com/2504-3900/2/8/406

Local defect resonance (LDR) makes use of high frequency vibrations to get a localized resonant activation of a defective region. In this study, the LDR behavior of carbon fiber reinforced polymer (CFRP) coupons with three different types of damages is investigated using broadband measurements obtained with a scanning laser Doppler vibrometer (SLDV). First, the LDR response of flat bottom holes of different depths and sizes is evaluated using a signal-to-noise ratio. Next, results are obtained for ETFE inserts where the difference between (artificial) delaminations and inserts is outlined. At last, the vibrational response of a CFRP coupon with barely visible impact damage is investigated. This type of damage has a more complex structure, and it is shown that frequency band data (an alternative to the single frequency LDR) performs well in identifying such complex damage.