Fatigue test

[RICKPICK]

I am new to the world of fatigue test. I am looking to carry out a test at load ratio of 0.1 My question is whether a constant stress is to be maintained all thought the test of a constant load (sigma max - sigma min) is to be controlled. What constitutes a fatigue cycle is it constant stress or load? if it is load then how is it different from creep.

appreciate your feedback

Thanks

 

[FeX32]

The stress is proportional to the load.
What kind of fatigue? Are you looking at a fully reversed or cyclic in one direction?
Fatigue is a rather empirical world that has no perfect analytical estimations.



Fe

 

[BiPolarMoment]

We often run tests with the same ratio (non-reversed) but it's solely the load that is controlled.

A purely stress vs. cycle curve seems difficult to determine and wouldn't it almost certainly be equivalent to a load vs. cycle curve? (Depends on application, of course)

 

[hacksaw]

creep is the deformation that occurs under constant stress at high temperature

fatigue failure is a function of cyclic stress applications. it can be tested under fully reversed stress cycles or a combination of constant load with a time varying component.

your load ratio may be a description of the ratio of constant to cyclical load

 

[izax1]

I was a bit puzzled about the question since this is posted in the Mechanical Acoustics/Vibration engineering forum. Does this have anything to do with the Acoustics/Vibration forum?