Nondestructive Determination of Ply-layup Error in Cured/Uncured CF/Epoxy Composites

摘要

A nondestructive technique would be very beneficial, which could be used to test the part before (uncured) and after curing CF/Epoxy. A new method for nondestructively determining the ply layup in a composite laminate is presented. The method employs a normal-incidence longitudinal ultrasound to perform C-scan of ply interfaces of the laminate, and extracts fiber orientation information from the ultrasonic reflection in the laminate. Using two-dimensional spatial Fourier transform, interface C-scan images were transformed into quantitatively angular distribution plots to show the fiber orientation information therein and to determine the orientation of the ply. In order to develop these methods into practical inspection tools, an automated system using a motor has been developed for different measurement modalities for acquiring ultrasonic effects of ply-layup error. Therefore, it is found that the efficiency of developed system shows between the practical testing and model in characterizing cured/uncured ply-layup error of the laminates. A C-scan image of a ply interface seem to have the ply-layup error information of the two neighboring plies of CF/Epoxy composite laminates.