Strain controlled Fatigue testing - what strain rate?
Strain controlled Fatigue testing - what strain rate?
(OP)
I am going to run some ambient temperature strain controlled fatigue testing (for the first time) on stainless steel (13-8PH). I am working in accordance to ASTM E606-04, but while the standard recommends testing to a constant strain rate, it does not advise a value. Could anyone provide guidance on appropriate strain rate?
Also what is the best way to determine a good starting point for the strain amplitudefor the first specimen.
Thank you.
Also what is the best way to determine a good starting point for the strain amplitudefor the first specimen.
Thank you.





RE: Strain controlled Fatigue testing - what strain rate?
It may help to understand what you intend to do with the strain- life fatigue results. For example, what is the application for the stainless steel in service?
RE: Strain controlled Fatigue testing - what strain rate?
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RE: Strain controlled Fatigue testing - what strain rate?
For the OP, there is no standard value for strain rate. What I would suggest is look at the purpose of the fatigue testing and decide on a strain range. Once this is known, you can select a frequency as mentioned above, and know you have a defined strain rate (strain/cycle, cycle/second). The unknown is total strain range and this must be defined by the service application.
RE: Strain controlled Fatigue testing - what strain rate?
The intention is to establish values for the following parameters to enable more accurate FEA modelling of life limits for highly loaded components: -
Cyclic strain hardening coefficient and exponent.
Fatigue strength co-efficient and exponent
Fatigue ductility coefficient and exponent