strain gradient plasticity

I hope some of you may find this work interesting, the X-FEM non-linear code developed (incorporating linear elasticity, J2 plasticity, and Strain Gradient Plasticity) can be downloaded from www.empaneda.com/codes

Gradient plasticity crack tip characterization by means of the extended finite element method

Emilio Martínez-Pañeda, Sundararajan Natarajan, Stéphane Bordas

Computational Mechanics (2017)

I have implemented the rate-independent strain gradient plasticity framework of Niordson and Hutchinson (2003) in UEL. I was able to validate the results of the shear of infinitely wide thin layer between two rigid surfaces (Niordson and Hutchinson, 2003). However, the UEL subroutine fails to converge for the more complex problem of the shear of finite width slab. I suspect the convergence issues are arising out of internal elastic-plastic boundary conditions and the yield criteria. I have few doubts in this regard.

I hope some of you may find this work interesting:

Strain gradient plasticity-based modeling of hydrogen environment assisted cracking

Emilio Martínez-Pañeda, Christian F. Niordson, Richard P. Gangloff

Acta Materialia, 117, pp. 321-332

http://www.sciencedirect.com/science/article/pii/S1359645416305183

A pre-print is available at www.empaneda.com

Strain gradient plasticity modeling of hydrogen diffusion to the crack tip

E. Martínez-Pañeda, S. del Busto, C.F. Niordson, C. Betegón

International Journal of Hydrogen Energy

http://www.sciencedirect.com/science/article/pii/S0360319915315913

Hi all,

I have a strange question that has puzzled me since last almost one year.

There are many SG-plasticity models in the technical literature, sometimes categorized as lower-order or higher-order models.

The problem is :

the constitutive models include the gradient of plastic parameters (e.g. plastic slip).

European Commission' s JRC (Joint Research Centre) is organizing a workshop on physics based modeling of material properties and experimental observations in collaboration with METU (Middle East Technical University). The workshop will be held in Ankara on 22-23 October 2012.

The Workshop will include lectures by keynote speakers: W. Curtin, F. Dunne, L. Malerba, J-F Molinari, A. Needleman and B. Svendsen, and presentations by participants (oral or posters).