about Peridynamic fatigue model

[Lumos1110]

I would like to add a fatigue model with the following literature reference:DOI:10.2172/1160289
I have a question at the moment: we need to apply a sinusoidal load in a loop to calculate the strain in each bond when the maximum load is reached. However, there is a problem that for total time, the calculated key strains are different for different total times. @CWillberg @JTHesse

[JTHesse]

Could you maybe share your .yaml input file? Then we can take a look.

[JTHesse]

So your question is how to do this in PeriLab?
Sinusoidal load can be applied directly in the BC:

 BC_1:
      Coordinate: y
      Node Set: Node Set 1
      Variable: Force Densities
      Type: Dirichlet
      Value: a * sin(b * t + c) + d

[Lumos1110]

This I am aware of, but it creates a problem.
You could make a plane with the left side fixed and the right side stretched, using a quasi-static algorithm. dt=1s, then apply a sinusoidal load to the right side with stress ratio=0, and then determine the elongation of each bond. You will find that when the total time is taken 100s and 1000s their elongation is different.

[JTHesse]

Ok, so this is a general peridynamic question or is this somehow related to PeriLab?
If you would like to implement the functionalities mentioned in the Paper into PeriLab, go ahead and open a feature request.
There could be many reasons why you are seeing this behavior, especially with a self-made matlab code, but until we don't have a running example, it's hard to say.
I'm leaving this discussion open for now, maybe someone else can comment on your question.

[Lumos1110]

Ok, I've found the problem, my ultimate goal is to couple corrosion and fatigue in perilab, so I'd like to implement it step by step.
I just rewrote the implementation in perilab as you said and it's great!

[JTHesse]

Perfect, if you are ready and the tests are running add a pull request ;)