As we may know, non-local plasticity formulations are utilized to reduce mesh subjectivity and eliminate numerical instabilities like snap-back in the response behavior of the materials under plastic regime.
Just wondering which parameter(s) you prefer to "non-localize" to achieve better result? particularly, why averaging the internal variables (hardening/ softening/ cohesive strength modifier) is not recommended compared to plastic strain?
And the most important question: What is your recommendation in implementing strategy of such formulations? I'm trying to implement it in FORTRAN as a UMAT.
Is there any reference stating that "it is not recommended to average internal variables?" Actually plastic strain is also based on an internal variable (plastic multiplier or whatever you call it). If the plastic strain tensor is averaged over some elements, then the difference obviously is that in one case a tensor is averaged as opposed to a scalar.
I dont know what specific user subroutine is necessary to gather information from neighboring elements, but surely there must be one, if it is not UMAT.
I should rephrase that to “it is the simplest but not the most efficient way to implement non-local plasticity” it is mentioned in “Nonlocal Integral Formulations of Plasticity and Damage: Survey of Progress”, before eq 61, and in Planas (1993) paper that regularization of the softening parameter can be performed by scaling it with respect to the element characteristic size.
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