PhD position at Loughborough University: 'Plasticity in small length scales'

As one of the biggest Departments of its kind in the UK, the Wolfson School of Mechanical and Manufacturing Engineering has an international reputation for being at the forefront of technological innovation and for maintaining extensive links with industry.

Hisham's picture

Literature for Multi-surface plasticity

Dear all,


Can someone please guide me to comprehensive literature for implementing multi-yield surface plasticity in numerical codes. I am not sure if I, properly, understand the algorithm.


Thanks in advance

Best regards,




Hi all,

         My system got shutdown while running a job in Abaqus.15 Gb odb file was generated and now I am not able to open the odb file.It is saying some error about the format.Have anyone came across such a problem.

Pls help me


Zhiqiang Wang's picture

Abstract deadline extended: August 15. ISCM III, Taipei, December 2011, Minisymposium of "Multiscale Methods in Plasticity"

Abstract deadline extended to August 15, 2011 for ISCM III-CSE II in Taipei, Taiwan, December 5-7, 2011. Please submit your abstract to the minisymposium of "Multiscale methods in plasticity".


We invite the submission of abstracts for a Minisymposium of Multiscale
Methods in Plasticity at the Third International Symposium of
Computational Mechanics (ISCM III)
in conjunction with the Second
Symposium on Computational Structural Engineering (CSE II), which will
be held in Taipei, Taiwan, December 5-7 2011. Abstract submission
deadline is now August 15, 2011. Please check the conference website for more
details (

Equilibrium Correction for viscoplasticity

In general for incremental plasticity problems it is well known that one has to use an iteration scheme (Newton-Raphson, modified Newton-Raphson or Quassi Newton etc.) in order to achieve a converged solution for finite element equations. Is it also neccessary to have an iteration scheme for an incremental viscoplastic problems ? I am also attaching a paper where the authors have implemented an equilibrium correction scheme in the principle of virtual work, which is supposed to ensure convergence. I am not able to comprehend how it takes care of the convergence without any iterations. Any help would be highly appreciated.



Ductile damage modelling in ABAQUS

Hi all

I am M.Sc. sutdent in Istanbul Technical University and my research subject is comparision of several ductile damage models both computationaly and experimentally.

I am trying to compare ductile damage models such as Freudenthal,Cockroft,Ayada ,Brozzo etc. computationally using ABAQUS and seeking a way to implement these damage models in ABAQUS.

To obtain each models damage result individually should damage model be implemented in ABAQUS or can a regular tensile test results be used for calculation of damage values.

Could you please advise me for methodolgy to run a simulation to obtain ductile damage values accordng to models mentioned above.

Thanks in advance for your help.

Hakkı ISIK.

Masoud Rais-Rohani's picture

Post-Doctoral Fellow in Computational Structural/Solid Mechanics and Design

Applicants are sought to fill a post-doctoral position in
computational solid/structural mechanics and design. The selected applicant will work
closely with Prof. Masoud Rais-Rohani and his research colleagues and graduate
students at the Center for Advanced Vehicular Systems (CAVS) in the Bagley
College of Engineering at Mississippi State University. Applicants must have strong background
in finite element analysis with good knowledge of commercial codes such as ABAQUS, LS-DYNA, or MD Nastran.

Masoud Rais-Rohani's picture

Post-Doctoral Fellow in Computational Structural/Solid Mechanics and Design

Applicants are sought to fill a post-doctoral position in
computational solid/structural mechanics and design. The selected applicant will work
closely with Prof. Masoud Rais-Rohani and his research colleagues and graduate

Daniel Kiener's picture

In situ nanocompression testing of irradiated copper

Dear colleagues,

we recently published a paper on measuring bulk properties of irradiated copper from nanoscale samples:

Hope you find this interesting!



Daniel Kiener's picture

In situ nanocompression testing of irradiated copper

In situ nanocompression testing of irradiated copper

Dear Colleagues,

we recently published a paper on measuring bulk properties of irradiated from nanoscale compression samples:

Hope you find this interesting!



Kejie Zhao's picture

Lithium-assisted plastic deformation of silicon electrodes in lithium-ion batteries: a first-principles theoretical study

Silicon can host a large amount of lithium, making it a promising electrode for high-capacity lithium-ion batteries.  Recent experiments indicate that silicon experiences large plastic deformation upon Li absorption, which can significantly decrease the stresses induced by lithiation and thus mitigate fracture failure of electrodes. These issues become especially relevant in nanostructured electrodes with confined geometries. Based on first-principles calculations, we present a study of the microscopic deformation mechanism of lithiated silicon at relatively low Li concentration, which captures the onset of plasticity induced by lithiation.

Zhiqiang Wang's picture

Postdoc position available in Compuational Materials Modeling

The Department of Materials Science and Engineering in the College of Engineering at the University of North Texas (UNT) seeks highly qualified applicants for a postdoctoral researcher position in computational materials modeling. The successful candidate will work on multiscale modeling of defects and microstructures (e.g., dislocations, grain boundaries, etc), and damage and failure of materials to design and evaluate advanced superalloys for aerospace applications, as part of the federally-funded research program in the Institute for Science and Engineering Simulation (ISES).

1.    A PhD in solid mechanics, materials science, or mechanical engineering, or in a related area is required.

DEM modelling of granular flow

Hi iMechanica,

I want to start a discussion on the current status of DEM modelling of granular media. I know that Luding has published many papers in this area. Please add to the current research on granular flow modelling like viscoplasticity, hypoplasticity etc and the  numerical DEM methods.

Modeling Metal forming in Abaqus...

I'm currently working on my master thesis which is in the area of metal
forming simulation...

I have one question,,, when adding material plasticity in Abaqus using the
power law...

to what limit shall i go in the tabulated form is it to 100% plasticity or
to the maximum strain the material can take...

 in other word,,, if the power law is: σ =250*εp^0.123...

shall i inter the values till at σ=250, ε=1... or shall i stop at let say ε=0.25...



Lemaitre and Caboche mixed hardening model



I'm working in a cyclic loding metal deformation, and I'm interesting about mixed hardening models.


I need help to know what is the "Lemaitre and chaboche(1990)" mixed hardening model, do enyone know? Is similar to the Amstrong-Frederic model??? How is represented the isotropic hardening?





Dear Friends,

I have written a UEL for Strain Gradient Plasticity and is working well when i give Boundary condition as Concentrated force, But when i apply displacement boundary condition the it leads to 'system error 144'.

Iknow that system error 144 corresponds to division by zero or infinity, but then why it is coming in on displacement boundary condition is i am worried about.

I will be extremely helpful to anybody for any type of help on above problem.

Thanking you in advance


Jeffrey Kysar's picture

Measurements of Geometrically Necessary Dislocation Densities on Individual Slip Systems

We have recently published a paper on measurements of the density of geometrically necessary dislocations (GND) associated with wedge indentation of a single face-centered cubic crystal. The deformation field is two-dimensional and there are three effective in-plane slip systems that contribute to the plastic slip. We determine the lower bound on the total GND density with a three micrometer spatial resolution. We also show that in certain regions of the domain, the lower bound on total GND density corresponds to the exact total GND density. Therefore, in those regions we can determine the apportionment of the total GND density onto the individual slip systems.

Amit Acharya's picture

On the three-dimensional Filon construct for dislocations

(to appear in the Intl. Journal of Engineering Science)

 Robin J. Knops and Amit Acharya

 The relationship between dislocation theory and the difference of linear elastic solutions for two different sets of elastic moduli, derived by Filon in two-dimensions, is generalised to three-dimensions. Essential features are developed and illustrated by the  examples of the edge and screw dislocations. The inhomogeneity  problem is  discussed within the same context and related to Somigliana dislocations, and  in the limit  to the interstitial atom.

Crack Initiation with UMAT

Dear all,

      I want to model crack initiation and propagation for a user defined material, using Abaqus. When I try to model , I get the following error:


when I take out critical damage initiation, the model works fine; which means that it doesnt allow me to couple UMAT with crack initiation. Does anyone know how to handle this problem?

All the best,



Amit Acharya's picture

On an equation from the theory of field dislocation mechanics

(Paper to appear in Bollettino della Unione Matematica Italiana - Bulletin of the Italian Mathematical Union)

Luc Tartar and Amit Acharya

Global existence and uniqueness results for a quasilinear system of partial di fferential equations in one space dimension and time representing the transport of dislocation density are obtained. Stationary solutions of the system are also studied, and an in finite dimensional class of equilibria is derived. These time (in)dependent solutions include both periodic and aperiodic spatial distributions of smooth fronts of plastic distortion representing dislocation twist boundary microstructure. Dominated by hyperbolic transport-like features and at the same time containing a large class of equilibria, our system di ffers qualitatively from regularized systems of hyperbolic conservation laws and neither does it fi t into a gradient flow structure.

Controversy: Dynamic Peierls-Nabarro equations

In 2010,  Yves-Patrick Pellegrini published a paper in Physical Review B called

 Dynamic Peierls-Nabarro equations for elastically isotropic crystals.  with the abstract

Mubeen's picture

CISM Course: Plasticity and Beyond

Dear all,

please find information about the 5 day - course on Plasticity and Microstructures at CISM Udine, Italy.

The link is:

Flyer is attached.

Best regards,



Original post from CISM website:

Plasticity and Beyond: Microstructures, Crystal-Plasticity and Phase Transitions

June 27, 2011 — July 1, 2011


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