Thermo-Mechanical Fatigue Lifing ACT

Abhilash_G

Hello @kumarkartikeya ,

I have a few queries regarding the method to evaluate the parameters 'A,m & n' in the damage accumulation equation, which are as follows:

1) As per Ansys documentation, these parameters can be determined by the least square error minimization method using LCF experimental data at each temperature.

But for each temperature, I have LCF data at various strain rates ranging from 0.00001/s to 0.003/s. So could you please suggest if there is any guideline on which strain-rate to prefer to calculate A,m & n?

2) Do I need to prefer the highest strain rate data or the lowest?

3) OR, Do I need to include LCF data at all the strain -rates for a certain temperature to evaluate A,m & n?

Please let me know!

kumarkartikeya

You have three unknowns A,m and n at every temperature. So you need three data points, they can be three different strain rates or different strain ranges with constant strain rates. This will be for every temperature level you want to work with.

you can design experiment accordingly. Mostly users design their experiments to get these values.

Designing experiments is beyond support scope.