fatigue failure
It has been recognized that a metal subjected to a repetitive or fluctuating stress will fail at a stress much lower than that required to cause failure on a single application of load. Failures occurring under conditions of dynamic loading are called fatigue failures. Fatigue Failure
Fatigue failure is characterized by three stages :
* Crack Initiation * Crack Propagation * FinalFracture
This long term fatigue crack in a high quality component took a considerable time to nucleate from a machining mark between the spider arms on this highly stressed surface. However once initiated propagation was rapid and accelerating as shown in the increased spacing of the 'beach marks' on the surface caused by the advancing fatigue crack.
AA7076-T Specimins Before & After Testing. Photographs of the surfaces of AA7076-T6 specimens before and after testing are shown above.
It has been recognized that a metal subjected to a repetitive or fluctuating stress will fail at a stress much lower than that required to cause failure on a single application of load. Failures occurring under conditions of dynamic loading are called fatigue failures. Fatigue Failure
Fatigue failure is characterized by three stages :
* Crack Initiation * Crack Propagation * FinalFracture
This long term fatigue crack in a high quality component took a considerable time to nucleate from a machining mark between the spider arms on this highly stressed surface. However once initiated propagation was rapid and accelerating as shown in the increased spacing of the 'beach marks' on the surface caused by the advancing fatigue crack.
AA7076-T Specimins Before & After Testing. Photographs of the surfaces of AA7076-T6 specimens before and after testing are shown above.
No comments:
Post a Comment