Fatigue Cycles in Steel

[kodak79]

My understanding is that for a member subject to cycles of load but is always in compression does not have to be considered for fatigue failure.

With this in mind my question is thus, for a member subject to an alternating load that causes a beam to bend one way then the other, should the stress range be taken as the full amplitude of alternating stress (i.e. max. temsile stress to max compressive stress)or should it be half of this (max. tensile stress to zero stress line)?

My gut feel is that it should be the full range but this obviously make a big difference to the safe life so I want to ensure I am correct.

 

[metengr]

kodak79;
Yes, it should be the full stress range (max to min). There is plenty of information in the public domain on this topic.