Dynamic strain signals from embedded fiber Bragg grating sensors are used for experimental modal analysis in carbon fiber reinforced polymer plates. Throughout a series of impact tests, the change of eigen-frequencies due to damage is evaluated for different impact energies. A detailed numerical model including the damage pattern obtained from X-ray computed tomography images demonstrates that most of the frequency changes can be explained by a delamination type of damage, whereas the total delamination surface has an affine relation to the absorbed impact energy. A homogenized damage model, including two damage factors, allows to predict the change of natural frequencies for a known damage size. (C) 2011 Elsevier Ltd. All rights reserved.