Impact defect detection in carbon fibre composites 

(CFRP) by dynamic excitation

The examples shows carbon fibre panel with  impacts prepared by Airbus, Bremen. Similar carbon composites are used for the new Airbus A380F.

 
Airbus A380 F, computer graphic by I3m, www.airbus.com

The defects are prepared by impacts of different energies.  The defects become visible by dynamic excitation at their natural frequencies as show below.

front (measurement surface): No visible defects

back side

Defect visible at 17.873Hzl

Evaluated vibration mode