Reliability Engineering Snapshot http://www.resnapshot.com
A monthly illustrated collection of actual failure analysis case studies in the fields of corrosion, lubrication, machine design, material properties, people, and vibration.
Rotor Dynamics http://www.brad.ac.uk/research/mbdmst/rotordynamic/
Tutorial on rotating shafts, bearings, seals, out-of-balance systems, instability and condition monitoring. Each section contains links to commercial and non-commercial sites of relevance to that section.