QUANTITATIVE ASSESSMENT OF FIBER FRACTURE IN DAMAGED LAMINATES USING X-RAY RADIOGRAPHY

In this paper, a new technique for extracting quantitative information about fiber fracture from dye penetrant enhanced X-ray radiographs is described. In this new inspection method, the observer marks fiber fr acture zones on a digitized version of the radiograph depicting the da mage state. Image processing routines are used to isolate the marked f iber fracture zones, and then extract fiber fracture parameters such a s the length of the longest fiber fracture zone and the total length o f fiber fracture from the marked image. The technique has been used to quantify fiber fracture in graphite epoxy laminates damaged by either quasi-static contact loading or low-velocity impact. The residual str engths of these specimens were found to correlate well with the fiber fracture parameters, with specimens containing more fiber fracture exh ibiting lower residual strength.