Materials & Failure Analysis

Emphasis: Fasteners

Fasteners are unique in that they can experience all environments; they are used on cars, trucks, heavy trucks, earth movers, cranes, oil drills and rigs, piping, planes, trains, tanks, HMMWVs, wheelchairs, your home and appliances… you name the product and chances are good fasteners are used on it. As a result of all the possible environments and loading conditions, studying fastener failures affords the analyst to observe and be acquainted with a plethora of different materials, failure modes, and failure mechanisms.

Please see the Articles page for content discussing fastener mechanical properties, engineering and design, and specific issues with products.


Inclusions
Above: SEM secondary electron image (at 8000x magnification) of a low carbon resulfurized steel which fractured in bending when loaded perpendicular to the rolling direction. Failure mode is ductile dimple rupture matrix; also seen here are stringer inclusions which provides local weakness. This weakness is why the dimple rupture surrounding the inclusions is much larger as opposed to regions where stringers are not observed.