ABSTRACT
Fatigue cracks in metallic airframes are most commonly found at bolt-hole locations in joints where stress concentrations exist due to the circular cutout [1]. Bolt-hole fatigue cracks are the most common form of damage in metallic airframe structures as conœrmed by studies such as MONITOR conducted within the European Union [1]. Statistics from a major airframe teardown of a Tornado aircraft [2] indicate that fatigue cracks at holes for joints were the most prominent form of damage throughout the structure. Campbell and Lahery [3] report that bolt-holes were the second most common initiation sites of fatigue damage that led to major accidents of aircrafts between 1947 and 1983.
