Nondestructive Evaluation of Impact Damaged CFRP Laminates by Acoustic Emission during Flexural Loading

초록

The degree of damage and the progressive failure of carbon-fiber reinforced epoxy(CFRP) lamiantes previously damaged by low velocity impact were characterized by acoustic emission(AE) and ultrasonic C-scan. Both the tensile and compressive stresses were induced by flexural loading in the same specimen. With the increasing degree of impact damage, the stress level for the onset of AE activity prior to the major ply failure was increased. It was also found that the severer the specimens were damaged by impact, the narrower the delamination was confined in the central region at the fleural loading. Both the degree of impact damage and the residual strength appeared to be very much dependent on the laminates structure. For a specific laminate structure, however, the degree of impact damage or the residual strength can be estimated by AE measurements during flexural loading.