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Plasticity

Zhigang Suo's picture

Nonlinear viscosity

The attached notes are written for a course on plasticity.  When I update the posts, I will write a note on my twitter account:  https://twitter.com/zhigangsuo.  

Variation of Stress with Charging Rate due to Strain-Rate Sensitivity of Silicon Electrodes of Lithium Ion Batteries

Silicon is a promising anode material for lithium-ion batteries due to its enormous theoretical energy density. Fracture during electrochemical cycling has limited the practical viability of silicon electrodes, but recent studies indicate that fracture can be prevented by taking advantage of lithiation-induced plasticity. In this paper, we provide experimental insight into the nature of plasticity in amorphous LixSi thin films. To do so, we vary the rate of lithiation of amorphous silicon thin films and simultaneously measure stresses.

Zhigang Suo's picture

Viscosity

The attached notes are written for a course on plasticity.  I will update new posts on my twitter account:  https://twitter.com/zhigangsuo.  

Zhigang Suo's picture

Strain hardening

The attached notes are written for a course on plasticity.  I will update new posts on my twitter account:  https://twitter.com/zhigangsuo.  Rheology is the science of deformation. This science poses a question for every material: given a history of stress, how do we find the history of strain?

Zhigang Suo's picture

Plasticity

I am teaching this course this semester.  I'll post notes as I write them.  Links to the notes are listed in this post.  I will also notify updates on twitter:  https://twitter.com/zhigangsuo

Soud Choudhury's picture

Abaqus is not reporting any CEEQ in coupled temp-displacement step

Hi all,

I am modeling a simple coupled temp-displecment analysis with the following step information:

** MATERIALS

** 

*Material, name=Material-1

*Conductivity

 1e-06,

*Creep, law=HYPERB

44000., 0.005,   4.2, 45000., 8.314

*Elastic

60000., 0.34

*Expansion, zero=25.

 1.4e-05,

*Plastic

20.,  0.

60., 0.1

** 

** PHYSICAL CONSTANTS

** 

*Physical Constants, absolute zero=-273., universal gas=8.314

** STEP: Step-1

** 

jenda_z's picture

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 http://mech.fsv.cvut.cz/~milan/course2014.html. 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 2.2.2.1, 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

10.1016/j.finel.2014.05.016

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

kenneth 

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, blboyce@sandia.gov and copy Dr. Sharlotte Kramer, slkrame@sandia.gov. 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.
Regards
Farzad

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. 

Amit Acharya's picture

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: 

Hi

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.

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