The use of vibrothermography for detecting and sizing low energy impact damage of CFRP laminate

Abstract

The detection and evaluation of low energy impact damage of carbon fibre reinforced polymer (CFRP) laminate were investigated using vibrothermography. To this goal, four specimens were begun with low energy impact with different energies, followed by the detection using vibrothermography. The detection results show that the matrix crack is mainly located closer to the surface opposite to impact, while the delamination is mainly closer to the impact surface. Then, an iterative algorithm based on maximal entropy theory was proposed for thermal image segmentation and on this basis, the damaged area was determined. The obtained results show the damaged area increases with the increase of impact energy and the damaged area and impact energy may present an approximate linear relationship.