Damage Evolution Phenomena and Models

The goal of this article is to overview some of the structural health monitoring issues associated with the development and growth of structural damage. A brief summary of various structural failure modes is provided, with particular emphasis on cyclic fatigue. Although fatigue is one of the commonly recognized failure modes, it is problematic for structural health monitoring. The complexity of this mechanism leads to many subtle load history effects that must be recognized and captured to obtain an accurate prognosis of remaining fatigue life. The article concludes with a proposed “witness sample” method that could provide a cost-effective approach for monitoring structures for evidence of potential fatigue damage. Keywords: crack growth; failure modes; fatigue; fracture mechanics; structural health monitoring; witness sample