HIGH-RESOLUTION COMPUTED-TOMOGRAPHY AND IMPLICATIONS FOR FATIGUE-CRACK CLOSURE MODELING

Understanding the physical bases of a cracked sample's macroscopic res ponse to applied loading, e.g. fatigue crack closure, requires non-des tructive, microscopic quantification of the crack face separations as a function of applied load. Ideally, these measurements should cover t he entire crack Face. Non-destructive sectioning with high resolution X-ray computed tomograpby has been used for in situ observations of th e crack faces under applied load in samples of AI-Li 2090, and in this paper, the crack openings that were measured in the interior of the s ample are related to crack face geometry and to changes in the slope o f load-displacement curves. The implications of these results are disc ussed for physically based crack closure modelling.