Keywords
Citation
(1998), "Metal fatigue life enhanced", Aircraft Engineering and Aerospace Technology, Vol. 70 No. 3. https://doi.org/10.1108/aeat.1998.12770cab.038
Publisher
:Emerald Group Publishing Limited
Copyright © 1998, MCB UP Limited
Metal fatigue life enhanced
Metal fatigue life enhanced
Keywords Fatigue, Metals
Fatigue life of a structure can reportedly be increased by a factor of ten or more by the split-sleeve cold expansion process developed at Fatigue Technology Inc., Seattle, Washington. The basic procedure involves pulling an expansion mandrel through a correctly sized starting hole. The mandrel is prefitted with a lubricated split sleeve, which prevents hole damage, facilitates a one-sided process, and minimizes the pull force needed. A hydraulically operated puller unit pulls the mandrel through the sleeve in the hole, which expands the parent material out in a radial direction. This produces a zone of material around the hole that is in a state of compression. Residual compressive stress shields the hole from the effects of cyclic loads, which typically cause fatigue cracks to grow.
The process may reportedly be applied to any metal, including aluminium, titanium, and high-strength steels. Although primarily used in the aircraft industry, the technology is also applicable to rail, medical, and maritime components.
Details from Len Reid, Fatigue Technology Inc., 100 Andover Park West, Seattle, Washington 98188-2868, USA. Tel: +1 206 246 2010.