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Plasticity

LSDYNA UMAT- history variable choice

Hi,

I'm presently working on implementing anisotropic yield criteria in LSDYNA as UMAT.

I understand from the LSDYNA documents that effective plastic strain is a default history variable.  So when we code, can we omit the update of effective plastic strain as a history variable? If so, where is it stored and how is it retrieved during post-processing ?

Laurence Brassart's picture

Reactive flow in solids

By Laurence Brassart and Zhigang Suo

Abstract:

Post-doc position opening in POSTECH, South Korea

A postdoctoral researcher position is available in the area of sheet metal forming, plasticity theory, computational modeling of forming of advanced high strength steels, light-weight alloys  at POSTECH (Pohang University of Science and Technology) working under the supervision of Prof. Myoung-Gyu Lee. He/She will also work with Prof. Frederic Barlat who is a world famous scholar in the field of plasticity. Candidates with a strong background in plasticity theory, computational mechanics of sheet metals, failure analysis are highly encouraged to apply.

Amit Acharya's picture

Jump condition for GND evolution

Acharya, A., Jump conditions for GND evolution as a constraint on slip transmission at grain boundaries, Philosophical Magazine, 87(8-9), 1349-1359, 2007 (see attachment)

Solid/Fluid Mechacnics

Choose a channel featured in the header of iMechanica: 
Free Tags: 

Hi,

In my research i am trying to develop a new model for plastic deformation, and i suspect there is a strong similarity between

plasticity and turbulent flow !.

My question is: if there is workd done trying to apply Reynolds decomposition (Reynolds Stress) to the governing equations and solved plasticity problem in Solids?

thanks,

Yaron B.S.

Full time position with ANSYS Inc (Houston, TX)

ANSYS, Inc. has an immediate job opening in Houston, TX for a Technical Services Engineer.  This is a full time position.

The job entails providing advanced technical guidance on various aspects of computational Structural Mechanics to clients in industry and academia.

aschmidt's picture

Nanoscale analysis of plasticity and fracture of the sheet metal structures

A new paper concerned with Nanoscale analysis of plasticity and fracture of the sheet metal is published in ICCS proceedings and available at:

http://alexschmidt.net/research/iccs_nano_29.pdf

Tuncay Yalcinkaya's picture

Full scholarships available at European Commission funded workshop on physically based material modeling

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.

PhD Students/Post-doctoral Associates- North Carolina State University

Our group at North Carolina State University is hiring PhD students and Post-doctoral Associates in the areas of multiscale modeling, computational mechanics, fracture, and plasticity.

Interested parties should email  zikry@ncsu.edu, and send a cv with a few representative publications.

MA Zikry 

Amit Pandey's picture

Stress Relaxation

2012-07-10

I would like to seek comments on : Room temperature stress relaxation and governing mechanisms that contribute to the plasticity that occurs during this process. As, most of the available work on relaxation is done at elevated temperatures.

Please check more on this thread by hari@

node/12687

 I have also attach papers by Prof Hart and Prof Krempl that did throw some light on this particular subject.

stress relaxation- doubt

Attached herewith a classical paper by Hart on introducing a concept of constant hardness curves refuting that absolute strain should not be considered as a state variable.

 

The interesting part is he uses a stress relaxation test to prove the same. Stress relaxation test, here refers to a tensile test, where the test is stopped after say certain amount of plastic deformation. The stress drops a little, but the total strain is constant. However, it is argued that there is a small inelastic deformation, which is the cause of this load or stress drop.

 

EC FUNDED WORKSHOP ON PHYSICS BASED MODELING OF MATERIALS, Ankara, October 22-23

The objective of the workshop, co-organized by Joint Research Centre of the European Commission and Middle East Technical University, is to discuss the present status of physics based constitutive modelling of metallic materials and associated experimental methods.

The Workshop is funded by the European Commission's Integration and Enlargment Programme.  There is no cost for attending the Workshop. A limited number of scholarships is available for participants from the target countries (see attached flyer).

how to model user defined creep in ANSYS?

Hi,
Is there a place I can find explained examples or tutorials on how to model user defined creep in ANSYS?

 

I need to follow the creep law __>      effective creep strain (e at time t) = S. T. e^(-H)

 

S=(a0)^t.(sigma)^(a1) ;     T = t^(a2)+(a3).t^(a4)+(a5)t^(a6)   ; H = (a7)/[(theta)+273.16]

a0 to a7 are material constants.

I have the experimental data and tried to fit the curve in Ansys to obtain the material constants. 

I tried to follow the ansys help file steps. But facing erros messages.

German French Summer School 2012 - Hardening and Damage of Materials under Finite Deformations

Dear all,

We are pleased to announce the forthcoming Summer
School on “Hardening and Damage of Materials under Finite Deformations:
Constitutive Modeling and Numerical Implementation
”, which will take place in
Dortmund, Germany from September 3rd to 7th, 2012 and is organized by Prof.
Dr.-Ing. A. Erman Tekkaya of TU Dortmund and Dr. Tudor Balan of LEM3,
ENSAM Metz.

German French Summer School 2012 - Hardening and Damage of Materials under Finite Deformations

Dear all,

We are pleased to announce the forthcoming Summer
School on “Hardening and Damage of Materials under Finite Deformations:
Constitutive Modeling and Numerical Implementation
”, which will take place in
Dortmund, Germany from September 3rd to 7th, 2012 and is organized by Prof.
Dr.-Ing. A. Erman Tekkaya of TU Dortmund and Dr. Tudor Balan of LEM3,
ENSAM Metz.

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.

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.

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.

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