Plasticity

Panagiotis KOTRONIS's picture

Post Doc Position: Risk-based Selection of Constitutive Models for Geotechnical Analysis, EC Nantes (France)

Post Doc description:

Soil, as a typical natural material, has very complex behaviour which is very difficult to be accurately modelled. In geotechnical engineering, about half of the accidents are caused by insufficient designs. The soil’s constitutive model is the fundamental issue for modelling and analyzing soil-related engineering systems.


Notched tensile specimens and force-displacement response.

 Dear forum members,

I'm trying to simulate a tensile test (of ductile material) using smooth and notched specimens. I've started with a simple model without damage (isotropic von Mises plasticity implemented in ABAQUS) to compare the force vs. displacement response between simulations and experiments.


cdeng's picture

MSc position in computational materials science at the University of Manitoba

Two Masters' positions are now available for the winter semester (starting in January), 2013 on computational materials sciene in the Department of Mechanical and Manufacturing Engineering at the Unviersity of Manitoba. The potential student(s) will work on the thermostability and mechanical properties in nanocrystalline materials and crystalline/amorphous composites. Students with strong interests in atomistic simulations (MD, ab inito, monte carlo, etc.) and good programming skills (C, Fortran, etc.) are encouraged to apply. Intrested students please send a CV and inquires to Prof. Deng at dengc@ad.umanitoba.ca. More details about the position can be found at: http://home.cc.umanitoba.ca/~dengc/index.html 


saberelarem's picture

Deformation rates and localization of an active fault system

The Corinth Rift in Greece is one of the most active extensional regions in the Mediterranean area (Fig. 1). The Corinth Rift Laboratory project (CRL, http://crlab.eu) is based on the cooperation of various european institutions that merge their efforts to study fault mechanics and related hazards in this natural laboratory where numerous continuous observations are made. The present rift is asymmetric and deformation is very localized. Numerous GPS campaigns since 1991 indicate a stable opening rate of about 1.5 cm/yr over a width of 10- 12 km in the western part of the rift (Fig. 2). Continuous GPS stations installed 10 years ago start to reveal reliable vertical displacement (Fig.3). The seismic activity is localized in the upper 12 Km of the crust.


shahram's picture

ABAQUS 6.11.1 and suitable version of FORTRAN for writing a VUMAT subroutine?

I need to write a Vumat subroutine in ABAQUS 6.11.1, and I dont know where should I begin from exactly? can anybody help me with the suitable version of Fortran for this version of ABAQUS and the steps I need to take for writing a SUBROUTINE in ABAQUS?

 Thank you guys 


Shailendra's picture

Minisymposium on "Plasticity: Bridging the Scales from Micro to Macro" at IWCMM XXII, Baltimore, MD, USA (Sept. 24-26, 2012)

Dear friends and colleagues,

This is to inform you of the minisymposium

Plasticity: Bridging the Scales from Micro to Macro

to be organized at the 22nd International Workshop on Computational Mechanics of Materials (IWCMM XXII) and request you to consider submitting an abstract. The workshop will be held in Baltimore, MD, USA during September 24-26, 2012.


ansys problem

i am working on autofrettage process in a cylinder with end caps . and i have problems with it. which material model is better to be used , what is the proper element to model it .  what is the best  number of substeps ? and there are errors when i am trying to apply pressure load.


Mubeen's picture

FEAP - user element subroutines

Hi all,

my question is about the history data storage in FEAP.

I am writing element subroutine (elmt01) in FEAP 8.3  for a history dependent problem (crystal plasticity).

I have written the stiffness
matrix subroutine (stiff01), but it needs the data from the previous
solution steps (previous strains, stresses, plastic strains, dislocation
densities .... nh1,nh2=30 per point).


Yuanli Bai's picture

Two PhD student positions available at MMAE of UCF

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Jonathan Zimmerman's picture

Submit an abstract for IMECE-2012 sympoisum "Multiscale Perspectives on Plasticity in Metals"

My co-organizers and I invite you to submit an abstract to the upcoming symposium “Multiscale Perspectives on Plasticity in Metals” at the ASME 2012 International Mechanical Engineering Congress & Exposition (IMECE), to be held November 9-15, 2012 in Houston, Texas. This symposium will explore the unique challenges to understanding plastic deformation in metals and formulating material models that can accurately predict thermo-mechanical deformation. Presentations will cover experimental and modeling investigations of the physical mechanisms that control plasticbehavior in metals, and insight gained on incorporating these mechanisms into high-fidelity models and simulations.


Postdoctoral positions in statistical modeling of fracture and plasticity

We anticipate the opening of four postdoctoral positions in 2012 to work on statistical aspects of fracture and plasticity,  and in particular on size effects in the fracture of  disordered media and in microplasticity.  The positions will be funded by the ERC Advanced Grant 2011, SIZEFFECTS.

We look for candidates with a strong background in one or more of the following areas:
- statistical mechanics (scaling, critical phenomena, disordered systems)
- numerical modeling fracture
- dislocation dynamics simulations
- molecular dynamics simulations of mechanical properties of solids.


Notes on thermoplasticity

I've recently had the opportunity to take another look at plasticity in the large deformation context.  I've avoided going into geometric and other issues involved with multiplicative deformations (points stressed in earlier blog posts by Giovanni (http://imechanica.org/node/11545), Arash (http://imechanica.org/node/11623)  and Xiabo (http://imechanica.org/node/11599).  Attached are some old notes that I'd prepared some years ago to help me with the details.  I hope they're of use to other students of mechanics.

-- Biswajit


Siamak60's picture

Linking error for Abaqus and Fortran

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Oden Warren's picture

EXTENDED ABSTRACT SUBMISSION: Nanobrücken II: A Nanomechanical Testing Workshop, March 22-23, 2012, INM Saarbrücken, Germany

Dear Colleague:

You are cordially invited to attend Nanobrücken II:  A Nanomechanical Testing Workshop, jointly presented by INM - Leibniz Institute for New Materials and Hysitron, Inc., with co-sponsorship from the JEOL company. This is the second workshop in the Nanobrücken series. The workshop's scope has been broadened, and the abstract submission deadline is now February 19, 2012.


Suvranu De's picture

Postdoctoral postion in Computational Crystal Plasticity at RPI

There is an immediate opening for a postdoctoral research position in the Advanced Computational Research Lab at RPI, Troy NY to work on Crystal Plasticity Finite Element Methods. Currently we are working on interesting advances in the areas of radiation damage and high strain rate loading conditions. Encouraged to apply are creative, self-motivated individuals with a sound baclkground in computational mechanics, CPFEM and materials science. RPI is home to the CCNI, one of the most powerful university-based supercomputational research facilities in the world.

 

Qualifications:

1. PhD in Computational/Applied Mechanics/ Computational Materials Science or related field.


What is the basic difference between Deformation theory and flow theory of plasticity ?

I am familiar with the flow theory version of the plasticity theory but still quite confused with the deformation theory version of the same.

When a material is modeled using a non-linear elastic model to predict its plastic behavior with no distinction between the elastic and the plastic strain, is it a deformation theory in that case?

Any elaboration in this regard would be really helpful.

Thanks in advance. 


ABAQUS VUHARD subroutine problem

Hello

I am working on the simulation of ring rolling. I have written the subroutine for the plasticity part in the subroutine VUHARD and have set the PLASTIC part in material definition to USER.
I dont have HARDENING PROPERTIES so i have set it BLANK. i have set the path of the subroutine in the job defintion part too. But abaqus crashes whenever i try to do DATA CHECK
It says ABAQUS KERNEL EXITED WITH AN ERROR.I dont know why this problem arises?. I am stuck.

The curve i want to define is yieldstress=K*plasticstrain^m*plasticstrainrate^n


Designing copper–zirconium based nanowires for improving yield strength and plasticity via configuring surface atoms

Following our previous work on Cu-Zr nanowire system, in this paper we have shown improvement in various thermo-mechanical properties of nanowire via manipulating the surface atoms. The paper titled "Designing copper–zirconium based nanowires for improving yield strength and plasticity via configuring surface atoms" by Vijay Kumar Sutrakarand D Roy Mahapatra has been published in Journal of Nanoparticle Research. The paper can be downloaded from
http://www.springerlink.com/content/j2786222101mn711/
The Abstract of the paper is given below:


Amit Acharya's picture

Anisotropic yield, plastic spin, and dislocation mechanics

(This paper is to appear in the IUTAM Procedia on "Linking scales  in
computations: from microstructure to macro-scale properties," edited by
Oana Cazacu)

Amit Acharya, S. Jonathan Chapman

With a view towards utilization in macroscopic continuum models, an approximation to the root-mean-square of the driving force field on individual dislocations within a "representative volume element" is derived. The plastic flow field of individual dislocations is also similarly averaged. Even under strong simplifying assumptions, non-trivial results on the origin and nature of anisotropic macroscopic yielding, plastic spin, and the plastic flow rule (for single and polycrystalline bodies) are obtained. A particular result is the dependence of the plastic response of a material point of the averaged model on the presence of dislocations within it, an effect absent in conventional theories of plastic response (e.g., J2 plasticity). Also noteworthy is the explicit geometric accounting of the indeterminacy of the slip-plane identity of the screw dislocation that appears to lead to some differences with conventional ideas.


Manaliac's picture

Tensile test under LS-DYNA

Dear all,

I would like to run a tensile test under ls-dyna of a mild steel  and
apply a 7000 N load to the dog bone specimen on a explicite scheme.

Unfortunately, I
have wild deformations ( and an error) on the nodes on edges where the
load is applied, so can you please tell me what are the importants
constants (like time termination, mass scale,...) and how to perform a
perfect run?

 

Have a good day,

 

Thank you

M.


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