strain gradient plasticity

On Tuesday 24th October at 3:00 pm (Italian time) Samuel Forest will offer the seminar “Strain gradient plasticity based on saturating internal variables” at the Department of Civil, Environmental, Architectural Engineering and Mathematics of the University of Brescia (Italy). Here attached please find the abstract of the seminar. 

Anyone may directly join online through Google Meet at 

https://meet.google.com/rad-ehjg-ker

"S15: Advanced modelling techniques: Higher-order continua" organised by Samuel Forest (Mines ParisTech CNRS) and Lorenzo Bardella (University of Brescia) http://emmc19.org/symposium-s15.html  

Abstract submission deadline: December 22nd, 2023, http://emmc19.org/submissions.html

Abhishek Arora, Rajat Arora, Amit Acharya

I hope some of you will find this work interesting. We present a new Weibull framework for cleavage fracture that incorporates strain gradient plasticity and can estimate the three parameters of Weibull-type models without any prior assumptions. A post-print is available at www.empaneda.com

Gradient-enhanced statistical analysis of cleavage fracture

Emilio Martínez-Pañeda, Sandra Fuentes-Alonso, CovadongaBetegón

European Journal of Mechanics - A/Solids 77, 103785 (2019)

I hope some of you may find this work interesting. We show, analytically and numerically, that strain gradient plasticity predicts the existence of an inner elastic field adjacent to the crack tip, reminiscent of a dislocation-free zone. The fact that elastic strains dominate plastic strains near the crack tip implies a paradigm-shift with respect to previous crack tip asymptotic studies in plasticity and gradient plasticity, which neglect elastic strains. 

Emilio Martínez-Pañeda, Norman A. Fleck

I hope some of you will find our recent paper in the Journal of the Mechanics and Physics of Solids interesting. The Abaqus user element (UEL) subroutine developed to implement strain gradient plasticity theories with energetic and dissipative higher order stresses (Gudmundson 2004, Fleck and Willis 2009) can be downloaded from www.empaneda.com/codes

The role of plastic strain gradients in the crack growth resistance of metals

Emilio Martínez-Pañeda, Vikram S. Deshpande, Christian F. Niordson, Norman A. Fleck

I hope some of you may find this work interesting:

Size effects in elastic-plastic functionally graded materials

Tittu V. Mathew, Sundararajan Natarajan, Emilio Martínez-Pañeda

Composite Structures, 204, pp. 43-51 (2018)

https://www.sciencedirect.com/science/article/pii/S0263822318313928

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

I hope some of you find this work interesting, the code with the control algorithm (Segurado and Llorca, 2004) to avoid convergence problems in cohesive zone model analyses of crack propagation can be downloaded from empaneda.com/codes (documentation and Abaqus input files are provided).

Non-local plasticity effects on notch fracture mechanics

Emilio Martínez-Pañeda, Susana del Busto, Covadonga Betegón 

Theoretical and Applied Fracture Mechanics (2017)

Micromechanics-based Nonlocal Continuum Models organised by Lorenzo Bardella (University of Brescia) and Samuel Forest (Mines ParisTech CNRS) http://www.esmc2018.org/drupal8/node/96  Submission deadline: November 15th, 2017  Nowadays, problems involving more physics and more length and time scales have become very relevant in engineering applications. Theoretical frameworks limited to conventional continua are often inadequate to model such problems.

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

The group of Mechanics of Solids and Structures at the School of Engineering at the University of Brescia (Italy) has an open PhD position. The appointment will begin on January 1st 2014 for three full years.

The following topics are of interest:

1. small-scale plasticity of metals, with emphasis on modelling the size effect through strain gradient plasticity theories and dislocation mechanics. 2. micromechanics of composite materials, with emphasis on modelling failure.

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).

who  can tell me more about the critical thickness theory ?I will be very excited if you   can introduce some reference to me.I know that critical thickness theory is solved rigorously and ursed to validated a useful approximation which is combined with slip distance theory modified for a finite structure size . (physical life review letters :elastic limit and strain hardening of thin wires in torsion)

 dear everyone,

I want to ask if anyone deal with strain gradient proposed

by fleck eat. in 1994 and 1997, using subroutine in ABAQUS ?