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Modeling of Localized Inelastic Deformation 2014

Dear colleagues,

I would like to bring to your attention the advanced course on Modeling of localized inelastic deformation that will be taught by Milan Jirasek in Prague, Czech Republic on 15-19 September 2014. More detailed information on the course is posted at We are looking forward to seeing you in Prague!

Weijie Liu's picture

Plasticity integration: satisfaction of the consistency requirement

Dear all,

I am trying to formulate the return mapping algorithm with Hill48 yield condition, isotropic hardening law and flow rule referenced to Simo & Hughes (Computational Inelasticity).

In section, equation (2.2.9) expresses the Kuhn-Tucker complementarity conditions:

ryellava's picture

Numerical approximation of tangent moduli


In this study, we presented a numerically robust procedure to evaluate 4th order tangent moduli which are vital for acheiving quadratic convergence of global Newton-Raphson scheme.

In this study, the proposed method is verified for hyperelastic models alone. However, the same can be extended to other constitutive models.

The paper can be found at

Numerically approximated Cauchy integral (NACI) for implementation of constitutive models


plasticity of orthotropic material in abaqus cae

dear all

 do anyone know how to simulate the plasticity of orthotropic material in abaqus cae?

  your help will be highly appreciated.

 best wish


The 2nd Sandia Fracture Challenge is here!

update, 7/24/2014: The information packet ("SFC2-challenge-v5.ppt") is no longer attached to this post (iMechanica has a file size limit of 1 MB, so we can not attach the 6 MB file). IF YOU WOULD LIKE THE INFO PACKET, PLEASE E-MAIL ME, and copy Dr. Sharlotte Kramer, If you have an older version of the information packet, please also e-mail for the newest (v5) info packet.

We intend to send the shear calibration data to all those whose e-mail address I have by August 1st (sorry for the delay!).

Combined hardening parameters

Hi everyone
I am trying to use Abaqus with combined hardening (kinematic + isotropic ) material. Structural milled steel strain-stress curve was obtained through tensile coupon test (ASTM E8).
Please let me know how I can extract material property (C , ɣ , Q and b ) for property input?
It is my first approach to martial plasticity so any detailed explanations or examples would be appreciated.

jsegurado's picture

24th International Workshop on Computational Mechanics of Materials (IWCMM 24) in Madrid, Spain, on October 1st-3rd 2014

The abstract submission for the 24th International Workshop on
Computational Mechanics of Materials (IWCMM 24) in Madrid, Spain, on
October 1st-3rd, 2014 is now opened. The deadline for abstract
submission is June 15th, 2014.

The workshop is intended to cover all aspects of modeling and
simulations of the mechanical behavior at different length and time
scales. The materials of interest range from traditional materials such
as metals, alloys, polymers and composites to advanced and emerging
materials and bio-materials.

ductile behaviour

I have done flat plate tensile test experiment with plate having u notch at different angle to get mixed mode behaviour.The experiment shows the force variation F(30 DEG)>F(45 DEG)>F(0 DEG)>F(60 DEG) While fem elasto-plastic model made in abaqus shows F(0 DEG)>F(30 DEG)>F(45 DEG)>F(60 DEG).

Can anyone tell me why this contradiction is there between experiment and fem model. 

From dislocation motion to an additive velocity gradient decomposition, and some simple models of dislocation dynamics

Amit Acharya         Xiaohan Zhang

(In Ph. G. Ciarlet and Ta-Tsien Li, editors, Proceedings of the International Conference on Nonlinear and Multiscale Partial Differential Equations: Theory, Numerics and Applications held at Fudan University, Shanghai, September 16-20, 2013, in honor of Luc Tartar. Series in Contemporary Applied Mathematics. Higher Education Press (Beijing), and World Scientic (Singapore), 2014)

Prager's Hardening Rule

Hi all

I am currently investigating Prager hardening room which is stated as the simplist linear kinematic hardening rule. I was wondering if anyone has worked with this model and if so if you have managed to identify how to determine the constant used for the back stress equation


dα =C * dεp ( this is epsilon dot p which is the equivalent plastic strain)


Please can you let me know how to determine the constant C from experimental results? 

Curve Fitting for Viscoplastic (Anand) Model in ANSYS

Hello everyone, 

            I would like to know if it is possible to use TBFT option in ANSYS to curve-fit Anand's model parameters using experimental force-displacement data.

     I am aware that the ANSYS manual  has description for hyperelastic and even chaboche model, but is there an established procedure to obtain Anand model parameters using experimental curve fitting ? 


Thank you. 

Measurement of the Bauschinger Behavior of Sheet Metals by Three-point Bending Springback Test with Pre-strained Strips

In numerical simulation of sheet metal
forming process, the cyclic mechanical behavior of metallic sheet is
required to calibrate the material parameters of the combined
isotropic-kinematic hardening model. Therefore the development of
experimental device and method is an important work in order to
measure the cyclic mechanical behavior of metallic sheet. There are
several experimental devices which can measure this cyclic mechanical
behavior of sheet metal mainly to measure the Bauschinger behavior.
Often, these experiments can be classified into three main
categories: (i) in-plane tension-compression test; (ii) in-plane
cyclic simple shear test; (iii) bending-reverse bending test.

In this paper, a novel approach is

Evading the strength-ductility trade-off dilemma in steel through gradient hierarchical nanotwins

It is a long-standing goal in metallurgy to enhance the strength of materials without sacrificing ductility. In a recent article in Nature Communications, we reported an effective way to evade the strength-ductility trade-off dilemma in twin-induced plasticity steel.

Inelasticity of Materials:An Engineering approch and practical guide by Arun Srinivasa

Choose a channel featured in the header of iMechanica: 


Has anyone followed the book Inelasticity of Materials by Arun Srinivasa?

 I was interested in the way he used lumped parameter models to describe material behaviour in Chapter 3. Trying to follow his methodology I wanted to implement it for some experimental results I have.

 However, I have faced an obstacle in trying to work out the hardening modulus of the the material in question. He has worked it out for his example case by curve fitting but I am just not getting the answer.

Modeling associative Tresca plasticity in ABAQUS?


I have a simple question. How could I model associative Tresca plasticity in ABAQUS?

 I use Property module: material editor: Mechanical:Plasticity:Mohr Coulomb Plasticity

I know that In the case (friction angle=0) of  the Mohr-Coulomb model reduces to the pressure-independent Tresca model with a perfectly hexagonal deviatoric section. 

Computational Mechanics Engineer

Computational Mechanics Engineer

Third Wave Systems, a leading
provider of CAE analysis software and services for machining manufacturing, is
seeking enthusiastic additions to our computational mechanics software
development team.  This position holds
the primary responsibility of developing and implementing numerical methods,
finite element formulations, smooth particle hydrodynamics (SPH), meshless
methods, adaptive and initial mesh generation, three-dimensional geometry
engines, mechanistic machining models, constitutive models for the simulation
and optimization of metal, composite, and ceramic cutting processes.  The Computational Mechanics Engineer (CME) will

Trung N Nguyen's picture

Postdoctoral researcher position opening at Pohang University of Science and Technology (POSTECH), Korea

We are seeking a highly qualified candidate for a full-time postdoctoral researcher position in the area of Computational Mechanics at the Graduate Institute of Ferrous Technology (GIFT), Pohang University of Science and Technology (POSTECH), Korea. Candidates with a strong background in continuum/dislocation-based plasticity theory, computational mechanics of sheet metals, FE modelling of sheet metal forming processes… are highly encouraged to apply.

Post Doctoral Research Associate at Loughborough University



The project will form one of the integral parts of a collaborative UK/India research grant, which is funded by the EPSRC and the Department of Science and Technology, Government of India.

Duration: 1 year

Deadline for application: 25 March 2014  


The projects aims to:


Abaqus 2d contact model not working




Sorry in advance, but this will be a long story...
Thank you for taking the time to look at it! :)


I have a 2D model that worked fine until a couple of
days ago where I tried changing the mesh a bit. Now when I try to run it aborts
calculation and gives some of the following errors:


- There are 14 unconnected regions in the model.

Symposium on Structure, Plasticity and Fracture of Inorganic Glasses in Paris

Dear Colleagues,

we are organizing a symposium on Plasticity and Fracture in Inorganic Amorphous Materials at 

Condensed Matter in Paris 2014

to be held August 23 to 29, 2014. 

Your experimental or theoretical contributions are highly welcome. 
Please don't hesitate to contact us for more information.

The deadline for abstract submission is  April 1st 2014.

Looking forward to seeing you in Paris in August,

Jean-Pierre Guin, Etienne Barhel and Erik Bitzek


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