Predicting Creep Failure from Cracks in a Heterogeneous Material using Acoustic Emission and Speckle Imaging

Abstract

Predicting the ``when'' of material failure has a wide range of applications, but how far in advance that prediction can be made is not clear. This study follows the advancement of cracks under creep (constant load) conditions, showing that although intermittent crack propagation results in acoustic emission (AE), analysis of the AE-event data cannot be used for reliable predictions. An optical-speckle technique is then employed to measure the length scale of the fracture process, which $c\phantom{\rule{0}{0ex}}a\phantom{\rule{0}{0ex}}n$ be used to predict when a sample fails. These results should be of interest for $e.g.$ monitoring the stability of structures or machinery.