# Plasticity

## 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

## 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

## 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.

## 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

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

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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.

## Modeling associative Tresca plasticity in ABAQUS?

Hi

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

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

## Abaqus 2d contact model not working

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Hi

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.

## regarding Microstructure analysis in ABAQUS

Hi all,

I am doing microstructure analysis in 3D. To implement anisotropy, i need to give the orientation data. Does anyone know, how to give the orientation in ABAQUS?

The data i have in hand is Euler Angles... Can i give the data manually for four of five grains?