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Plasticity

S. Beretta's picture

Research assistant and PhD position at PoliMi on micro-plasticity models

In the last decade, different
cyclic plasticity models
, based on the “continuum” approach, have been proposed
in order to account for different mechanical effects (such as ratchetting,
strain range dependence, non-proportional loading and memory effect), [1, 2]. A
disadvantage of this approach is the elevated number of model parameters
introduced in order to correctly predict the material behaviour. The determination
of these parameters, usually difficult and expensive,
is one of the reasons why the modern
constitutive models are not widely used in finite element simulations of

Robin Selinger's picture

APS March Meeting Focus session: "Fracture, Friction, and Deformation Across Length Scales"

Abstracts due Friday, Nov. 19, 2010 

APS March Meeting Focus session: "Tribophysics: Friction, Fracture and Deformation Across Length Scales"

March 21 - 25, 2011, Dallas, Texas
Details at
http://www.aps.org/meetings/march/scientific/focus2.cfm#12.7.3

Invited speakers: Michael Marder (Univ. of Texas); Julia Greer (Caltech)

Amit Acharya's picture

Microcanonical Entropy and Mesoscale Dislocation Mechanics and Plasticity

(Journal of Elasticity, Carlson memorial Volume)

A methodology is devised to utilize the statistical mechanical entropy of an isolated, constrained atomistic system to define the dissipative driving-force and energetic fields in continuum thermomechanics. A thermodynamic model of dislocation mechanics is discussed. One outcome is a definition for the mesoscale back-stress tensor and the symmetric, polar dislocation density-dependent, Cauchy stress tensor from atomistic ingredients.

Plasticity Data in Vumat

Hello everyone,

  I am using a VUMAT with isotropic hardening in my three dimensional model. Can someone tell me how is plasticity data passed into this subroutine? In VUMAT for kinematic hardening we define the yield stress and hardening modulus along with E and poisson's ratio in *User Material. I did not find any isotropic hardening VUMAT examples in manual. Do we define the hardening modulus or the yield stress-plastic strain data in isotropic hardening VUMAT? I will be really thankful if anyone can help me.

 

Thank you

Swapnil

Disparity in Simple Shear solution in ABAQUS

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Dear All,

Eran Bouchbinder's picture

A new postdoc position is available

A new postdoctoral position in continuum mechanics is available at the Weizmann Institute of Science. Candidates should have a strong background in physics and/or theoretical mechanics, as well as experience with analytical and computational methods for solving partial differential equations. Possible projects include the mechanics of frictional sliding, the mechanics of biomaterials, the mechanics of glassy materials and dislocation-mediated plasticity. Highly motivated candidates are requested to send their CV, publications list and statement of research interests to Dr.

vicky.nguyen's picture

Mechanics of Materials: Textbook Recommendation

I will be teaching a sophomore level class  mechanics of materials class.  The class will cover mechanics of basic strength of materials (e.g. beams, pressure vessels), but I also want to teach basic elements of failure mechanics (fracture, fatigue, plasticity, and wear.)  I'm looking for a recommendation of an undergrad mechanics textbook that covers the fracture, fatigue, plasticity, and wear.  The students will have had a statics and mechanics class and their textbook already covers strength of materials.  Thanks.

Shabeer Khan's picture

plasticity

Good Time to Everybody, I am working on Thermoplasticity, especially thermoviscoplasticity, will be comparing the results of some basic examples problem worked be Simo and Miehe, modelled in Abaqus with the results of a locally developed code. I am new comer in this excellent forum and I am happy to see myself among a nice community of Mechanicians. I regard all those who are conneted in this form and those who helped in connecting this chain of  Mechanics.

 

benzerga's picture

How do ductile materials fail?

This is a review on ductile fracture committed to the Advances in Applied Mechanics (Vol 44). Part of the review has an educational purpose and, as such, is intended for advanced undergraduates and starting graduate students. The other part is an account of recent research conducted in the field.

johnsmart1987's picture

plasticity induced fatigue crack closure

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hi friends am doin my my project on" FEA of plasticity induced crack closure". my specimen size is 80*80 mm. by using symmetry condition i modelled 1/4th of model in ANSYS. therfore i created 40*40 mm plate. with initial crack length of 4mm.means its MT specimen of 80*80mm with 8 mm crack length, by symmetry condition i modelled 40*40 with 4mm crack lenth.

Low cycle fatigue/Ratcheting

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Hi viewers,

S-N curve

I am working on plastic behaviour of metal. I am using Abaqus 6.7 for simulation of uniaxial ratcheting of steel under cyclic loading. Modelling and job submission/completion has been done successfully. But I cann't understand  where  the data for Stresses(S) &  number of cycle(N) is strored to draw S-N curve. Please suggest.

concrete damaged plasticity considering strain rate

Hi all,

Concrete is sensitive to strain rate. I want to create a model for a reinforced concrete plane frame. The material model used for concrete is concrete damaged plasticity, and the element type is B21. I want to consider strain rate effects of concrete(strength). The problem is that ABAQUS can not work after considering strain rate effects of concrete when the concrete yields. Can you help me? Thank you in advance.

help about secnd order effect in columns

ello all,

I am an M.S student, my subject in modelling of high strength concrete column under eecentric loading. I made a model of reinforced

 concrete column with in ANSYS by solid65 to represent concrete and link8 for steel.

My model is 200*200*4000 mm, i choose multi., conc.,and elastic linear for concrete, closing crushing for it, for steel bilinear, elastic.

Heip to get second order effect in reinforced concrete column

Hello all,

I am an M.S student, my subject in modelling of high strength concrete column under eecentric loading. I made a model of reinforced concrete column with in ANSYS by solid65 to represent concrete and link8 for steel.

My model is 200*200*4000 mm, i choose multi., conc.,and elastic linear for concrete, closing crushing for it, for steel bilinear, elastic.

Modellilng Deep and shallow foundations in Abaqus

Dear All,

I decided to put this post since I am trying to model piles on granular materials with Abaqus and I am having LOADS of problems, some of them due to my lack of understanding in the subject and others becasue there is not enough information around. Some of my problems are:

1- convergence problems: I am using Mohr coulomb for the soil and elasticity for the pile. If the difference between Young's modulus for both materials is to big it does not converge on Abaqus Static. If I do not put a bit of cohesion in my soil it also does not converge.

PhD positions in Computational Mechanics

We are looking for suitable candidates for a PhD research work in Computational Mechanics and numerical simulation, to be carried out at the Department of Mechanical Engineering, University of Aveiro, Portugal, in one of the following areas:

- development of new finite elements for metal forming applications;

- numerical simulation of metal forming (sheet and bulk forming);

- tubular hydroforming numerical simulation;

- structural stability and buckling analysis of reinforced aircraft panels;

Survey on XFEM: is XFEM good at characterizing Failure rather than Fracture?

Would like to hear your expertise/user/non-expert/sceptic comments on XFEM. Here are some of the challenges. Would like to hear your relections.

1. Can XFEM be utilized in characterizing Failure rather than Fracture?

2. What sort of challenges XFEM still have with respect to Fracture Mechanics?

3. How the Fracture mechanics benefit the industry, from the perspective of strcutural integrity?

4. Failue investigations vs. Fracture investigations: benefit to industry?

5. Academist vs Engineer: Perspective on XFEM

notch tip radius

Hello everyone,

 

I am looking for a way to measure notch tip radius experimentally. Would you give me some ideas about that? is there any relationship between  morphology of notched cracked body surface and notch tip radius?

 Thank you and Regards, 

Dynamic simulations with nonlinear material into Explicit

Hi all,

 I am new in the Forum, and I am looking for some informations regarding how to simulate nonlinear material in explicit.

I am tryng to analyse the behaviour of a roller rolling on the sand (or mud), but the results I get with a basic elasto-plastic material are not very accurate, expecially because I cannot set the tension allowed in the sand to be zero.

Other ways to input nonlinearity in Explicit are always refused by ABAQUS. Is there any way to get something more accurate?

ABAQUS (6.8, 6.9 EF) - Effect of the number of back stresses

Since ABAQUS 6.8, a new feature has been added to the combined hardening
material input.

Let's assume a combined Kinematic and Isotropic hardening case, such as
those happen in metals.

"Half cycle" uni-axial test results has been utilized to model the yield
stress-plastic strain behavior as well as the Kinematic behavior of the
metals.

In the same user interface,  there is an option to choose the number of
back stresses.

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