In agreement with dislocation theory, recent experiments show, both quantitatively and qualitatively, how geometrically necessary dislocations (GNDs) distribute in dislocation wall and cell structures. Hence, GND density fields are highly localized with large gradients and discontinuities occurring between the cells. This behavior is not typical for strain gradient crystal plasticity models. The present study employs a higher order extension of conventional crystal plasticity theory in which the viscous slip rate is influenced by the gradients of GND densities through a back stress. A phenomenological back stress formulation is proposed, through which the effect of the GND gradient exponent can be studied. It is shown that this model can lead to more localized GND distributions.
|Title of host publication||Plastic Behavior of Conventional and Advanced Materials: Theory, Experiment, and Modeling : Proceedings of PLASTICITY ’15|
|Editors||Akhtar S. Khan|
|Number of pages||3|
|Publication status||Published - 2015|
|Event||21st International Symposium on Plasticity and its Current Applications - Hilton Rose Hall Resort & Spa, Montego Bay, Jamaica|
Duration: 4 Jan 2015 → 9 Jan 2015
Conference number: 21
|Conference||21st International Symposium on Plasticity and its Current Applications|
|Location||Hilton Rose Hall Resort & Spa|
|Period||04/01/2015 → 09/01/2015|
El-Naaman, S. A., Nielsen, K. L., & Niordson, C. F. (2015). Strain gradient crystal plasticity: A continuum mechanics approach to modeling micro-structural evolution. In A. S. Khan (Ed.), Plastic Behavior of Conventional and Advanced Materials: Theory, Experiment, and Modeling: Proceedings of PLASTICITY ’15 NEAT Press.