Reprint from LINK, Summer 2020
A number of years ago I owned an old John Deere tractor that was clearly showing its age. As I tooled around my yard cutting the grass I noticed that the engine was laboring more and more and it was consistently blowing oily blue smoke from the exhaust. I knew it was time to either retire the tractor or rebuild the engine. Although I had never done it before, I decided I would try my hand at rebuilding the engine.
From Fasteners Technology International, April 2014
Anyone that has ever worked on rehabbing an older home has probably encountered a plumbing connection where an old galvanized steel pipe that has been connected with a newer copper fitting such as shown in Figure 1 is in bad shape. The discovery of this condition may be purely accidental, or more likely, if such a connection has been in-place for any length of time, the ticking time bomb represented by this condition has finally gone off and it is leaking or broken.
So what is this condition? It is a classic case of galvanic corrosion. Fastener engineers, designers and end users, especially in instances where metals are being clamped in wet environments, must be very wary of this possibility and make efforts to avoid future problems.
From Fasteners Technology International, August 2013
Although component failures have probably been around for as long as man has been putting things together, it wasn’t until the early to mid nineteenth century that engineers began studying the progressive failure mode that we know today as fatigue. Although highly undesirable, fatigue is a relatively common failure among fasteners and regretfully can lead to some dramatic and even life-threatening consequences. A great deal of progress in understanding fatigue has been made since the nineteenth century, and yet there is still much to be learned. Fortunately, enough is understood today that specific strategies and practices can be employed when a bolt or screw is designed in an application at risk of fatigue failure. This article will look at the basics of fatigue in fasteners and preventative measures that can be adopted to reduce the risk of failure and improve the durability or life of the fastener component.