Reducing operating cycles- (Using lower rotating speeds /Regular part replacement)
Selecting materials which are tolerant to cyclic loading (ductile /tough materials )
Reducing/eliminating the stress severe concentrations - (no sharp corners or sudden size changes )
Specifying manufacturing processes to provide fatigue resistance (Peening /shot blasting/Cold Working )
Specifying heat treatment to provide fatigue resistance- (Carburising /Nitriding )
Overdesigning part to reduce stress levels
Preloading to convert cycling load to steady load (bolt preloading)
Below are illustrated a number of methods of reducing stress concentrations....
Shafts
Screw Threads
Welds
Reduce weld created stresses by heat treatment (stress relieving /anealing).
Welds to be high quality with no cracks, porosity and slag inclusions.
Welds to have smooth profiles with no sharp corners at interface with parent metal. (Concave not convex weld surfaces...
Useful Links..
Metal Improvements ...->Shot peening - specialist in improving metal fatigue performance
Remember - the information on this site is for general information purposes only and while we endeavour to keep the information up to date and correct, we make no representations or warranties of any kind, express or implied, about its completeness, accuracy, reliability, suitability or availability. Any reliance you place on such information is therefore strictly at your own risk.
Roy Beardmore passed away on 9th March 2013. He is sadly missed. This website, Roymech, has been an invaluable resource for engineers around the world and we hope to maintain this incredible legacy going forward.
