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Increment size at specific times

Increment size at specific times

Increment size at specific times


For my model, I have implemented a UMAT, and at the end of each converged iteration, a parameter is calculated. The UMAT calculations need this parameter for further calculation.
So the values of my UMAT at time increment i depend on the parameter calculated in increment i-1, i.e. forward calculation. In order to make this more backward, I want adjust the time increments, as such that for example instead of increments at time 0, 1, 2, 3... I have increments at time 0, 0.001, 1, 1.001, 2, 2.001..
Then I can calculate the parameter for example at time 1, and at time 1.001 use this value in the UMAT.
Since I have a UMAT implemented I was thinking of using PNEWDT somehow, setting it to a very small value, but then the increment would stay small.
Is there another way of imposing a certain time increment in ABAQUS?

Note that I cannot calculate the parameter during the UMAT since it depends on the values of all elements (and the UMAT is called for each integration point).

RE: Increment size at specific times

I'm afraid that fixed incrementation (parameter DIRECT) and PNEWDT are the only options that can be used to control time increments. You can, however, force output at given time moments (using Time Points feature).

RE: Increment size at specific times

How does this 'time points' feature works? Does ABAQUS controls the increments such that the exact time points are reached? Or is it purely interpolation based on the converged increments?

RE: Increment size at specific times

By default Abaqus adjusts the increments so that the data is written exatcly at the specified time points.

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