Crystal plasticity is usually used to simulate the transient stress-strain behavior of metals. Recently, I have noticed some researchers using CPFE to simulate pure creep of polycrystalline materials. It is interesting that this can be achieved simply by adjusting the parameters of the plastic model. I don't quite understand this process.
I think this requires an additional analysis step in Abaqus. The first incremental step completes the loading of the force, and at the end of the incremental step, the elastic stress rate is set to 0. In the second incremental step, only the incremental shear strain generated by the shear stress is updated. This process is easy to understand, but it is not very clear how to implement it.
I do have made some attempts. Initially, I defined the shear strain rate as the power of the shear stress multiplied by a very small pre exponential coefficient. I derived NR and found that the increment of shear strain at the current and subsequent times is the same. Unfortunately, the model cannot calculate it. Afterwards, I made some attempts, such as changing the shear strain rate form of different analysis steps, and in the end, I did obtain a time creep curve. But I know this is wrong, there must be something missing, it's just because the values I set were relatively small, and the stiffness matrix just happened to be calculated. When I adjust to a relatively large shear strain rate, I cannot calculate it.
I would suggest approaching Mahmoud Mostafavi he might be interested to add to this discussion. I hope your research is rewarding.
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