Jawad | 11 Oct 14:36 2008
Picon

How to define Elasto-Plastic material property....

Hi;

I am facing a little difficulty in defining the elasto-plastic
material property in abaqus.

The model is bilinear kinematic hardening model, in which i need to
define the yield stress and tangent modulus (slope of the plastic
region).

In abaqus there is an option
Create Material -> Mechanical -> Plasticity -> Plastic
Its requires Yield Stress and corresponding Yield Strain but no
tangent modulus value. I dont have the value of plastic strain.

My other qs is how to define the elastic-perfectly plastic material
property in abaqus.

Thanks in advance....

Regards
Jawad Qarni

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Dave Lindeman | 13 Oct 16:23 2008

Re: How to define Elasto-Plastic material property....

You'll need to calculate the plastic strains by subtracting out the
elastic strain at each point on your stress-strain curve -- see the
Materials->Overview->Inelastic Behavior section of the Materials part of
the User's Manual (19.1.1 in the 6.8 documentation).

For an elastic-perfectly plastic material you simply need to define the
yield stress (which occurs at zero plastic strain):

*PLASTIC
yield stress,0.0

Regards,

Dave

-------------------------
Dave Lindeman
Lead Research Specialist
3M Company
3M Center 235-3F-08
St. Paul, MN 55144
651-733-6383

Jawad wrote:
>
>
> Hi;
>
> I am facing a little difficulty in defining the elasto-plastic
> material property in abaqus.
>
> The model is bilinear kinematic hardening model, in which i need to
> define the yield stress and tangent modulus (slope of the plastic
> region).
>
> In abaqus there is an option
> Create Material -> Mechanical -> Plasticity -> Plastic
> Its requires Yield Stress and corresponding Yield Strain but no
> tangent modulus value. I dont have the value of plastic strain.
>
> My other qs is how to define the elastic-perfectly plastic material
> property in abaqus.
>
> Thanks in advance....
>
> Regards
> Jawad Qarni
>
>

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Jawad | 14 Oct 17:58 2008
Picon

Re: How to define Elasto-Plastic material property....

Dear Mr. Lindeman
Many thanx for the elastic-perfectly plastic model. Sir can u plz be
a little more specific about the bilinear kinematic hardening.

For example here are some of the date values i have.....

Temperature(K)-Young Modulus(GPa)-Yield Stress(MPa)-Tangent Mod(GPa)
293.0 - 200 - 230 - 2.80
473 - 185 - 184 - 2.59

I will be very thankful to you if u could plz tell me how can i use
these values to calculate the "plastic strain" for the corresponding
yield stress value...

Once again thanx...

Regards
Jawad Qarni

--- In Abaqus <at> yahoogroups.com, Dave Lindeman <ddlindeman <at> ...> wrote:
>
> You'll need to calculate the plastic strains by subtracting out the
> elastic strain at each point on your stress-strain curve -- see the
> Materials->Overview->Inelastic Behavior section of the Materials
part of
> the User's Manual (19.1.1 in the 6.8 documentation).
>
> For an elastic-perfectly plastic material you simply need to define
the
> yield stress (which occurs at zero plastic strain):
>
> *PLASTIC
> yield stress,0.0
>
> Regards,
>
> Dave
>
> -------------------------
> Dave Lindeman
> Lead Research Specialist
> 3M Company
> 3M Center 235-3F-08
> St. Paul, MN 55144
> 651-733-6383
>
>
> Jawad wrote:
> >
> >
> > Hi;
> >
> > I am facing a little difficulty in defining the elasto-plastic
> > material property in abaqus.
> >
> > The model is bilinear kinematic hardening model, in which i need
to
> > define the yield stress and tangent modulus (slope of the plastic
> > region).
> >
> > In abaqus there is an option
> > Create Material -> Mechanical -> Plasticity -> Plastic
> > Its requires Yield Stress and corresponding Yield Strain but no
> > tangent modulus value. I dont have the value of plastic strain.
> >
> > My other qs is how to define the elastic-perfectly plastic
material
> > property in abaqus.
> >
> > Thanks in advance....
> >
> > Regards
> > Jawad Qarni
> >
> >
>

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Dave Lindeman | 14 Oct 21:59 2008

Re: Re: How to define Elasto-Plastic material property....

Given elastic modulus (E), yield stress (Sy), tangent modulus (Et), and
the maximum total strain (epsTotalMax)that you want to cover, the
bilinear curve can be defined as:

*PLASTIC
Sy,0.0
Sy+Et*[epsTotalMax-(Sy/E)],epsTotalMax-(Sy/E)

To see this, draw a bilinear curve and label Sy, E, Et, and epsTotalMax.

Regards,

Dave

-------------------------
Dave Lindeman
Lead Research Specialist
3M Company
3M Center 235-3F-08
St. Paul, MN 55144
651-733-6383

Jawad wrote:
>
>
> Dear Mr. Lindeman
> Many thanx for the elastic-perfectly plastic model. Sir can u plz be
> a little more specific about the bilinear kinematic hardening.
>
> For example here are some of the date values i have.....
>
> Temperature(K)-Young Modulus(GPa)-Yield Stress(MPa)-Tangent Mod(GPa)
> 293.0 - 200 - 230 - 2.80
> 473 - 185 - 184 - 2.59
>
> I will be very thankful to you if u could plz tell me how can i use
> these values to calculate the "plastic strain" for the corresponding
> yield stress value...
>
> Once again thanx...
>
> Regards
> Jawad Qarni
>
> --- In Abaqus <at> yahoogroups.com <mailto:Abaqus%40yahoogroups.com>, Dave
> Lindeman <ddlindeman <at> ...> wrote:
> >
> > You'll need to calculate the plastic strains by subtracting out the
> > elastic strain at each point on your stress-strain curve -- see the
> > Materials->Overview->Inelastic Behavior section of the Materials
> part of
> > the User's Manual (19.1.1 in the 6.8 documentation).
> >
> > For an elastic-perfectly plastic material you simply need to define
> the
> > yield stress (which occurs at zero plastic strain):
> >
> > *PLASTIC
> > yield stress,0.0
> >
> > Regards,
> >
> > Dave
> >
> > -------------------------
> > Dave Lindeman
> > Lead Research Specialist
> > 3M Company
> > 3M Center 235-3F-08
> > St. Paul, MN 55144
> > 651-733-6383
> >
> >
> > Jawad wrote:
> > >
> > >
> > > Hi;
> > >
> > > I am facing a little difficulty in defining the elasto-plastic
> > > material property in abaqus.
> > >
> > > The model is bilinear kinematic hardening model, in which i need
> to
> > > define the yield stress and tangent modulus (slope of the plastic
> > > region).
> > >
> > > In abaqus there is an option
> > > Create Material -> Mechanical -> Plasticity -> Plastic
> > > Its requires Yield Stress and corresponding Yield Strain but no
> > > tangent modulus value. I dont have the value of plastic strain.
> > >
> > > My other qs is how to define the elastic-perfectly plastic
> material
> > > property in abaqus.
> > >
> > > Thanks in advance....
> > >
> > > Regards
> > > Jawad Qarni
> > >
> > >
> >
>
>

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Jawad | 16 Oct 19:10 2008
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Re: How to define Elasto-Plastic material property....

Dear Sir;

Thanks a lot for the technical support... I have been able to
successfully implement this technique and also generated the graph
for verification which seems to be ok..

Once again thankyou

Regards
Jawad Qarni

--- In Abaqus <at> yahoogroups.com, Dave Lindeman <ddlindeman <at> ...> wrote:
>
> Given elastic modulus (E), yield stress (Sy), tangent modulus (Et),
and
> the maximum total strain (epsTotalMax)that you want to cover, the
> bilinear curve can be defined as:
>
> *PLASTIC
> Sy,0.0
> Sy+Et*[epsTotalMax-(Sy/E)],epsTotalMax-(Sy/E)
>
> To see this, draw a bilinear curve and label Sy, E, Et, and
epsTotalMax.
>
> Regards,
>
> Dave
>
> -------------------------
> Dave Lindeman
> Lead Research Specialist
> 3M Company
> 3M Center 235-3F-08
> St. Paul, MN 55144
> 651-733-6383
>
>
> Jawad wrote:
> >
> >
> > Dear Mr. Lindeman
> > Many thanx for the elastic-perfectly plastic model. Sir can u plz
be
> > a little more specific about the bilinear kinematic hardening.
> >
> > For example here are some of the date values i have.....
> >
> > Temperature(K)-Young Modulus(GPa)-Yield Stress(MPa)-Tangent Mod
(GPa)
> > 293.0 - 200 - 230 - 2.80
> > 473 - 185 - 184 - 2.59
> >
> > I will be very thankful to you if u could plz tell me how can i
use
> > these values to calculate the "plastic strain" for the
corresponding
> > yield stress value...
> >
> > Once again thanx...
> >
> > Regards
> > Jawad Qarni
> >
> > --- In Abaqus <at> yahoogroups.com <mailto:Abaqus%40yahoogroups.com>,
Dave
> > Lindeman <ddlindeman <at> > wrote:
> > >
> > > You'll need to calculate the plastic strains by subtracting
out the
> > > elastic strain at each point on your stress-strain curve --
see the
> > > Materials->Overview->Inelastic Behavior section of the
Materials
> > part of
> > > the User's Manual (19.1.1 in the 6.8 documentation).
> > >
> > > For an elastic-perfectly plastic material you simply need to
define
> > the
> > > yield stress (which occurs at zero plastic strain):
> > >
> > > *PLASTIC
> > > yield stress,0.0
> > >
> > > Regards,
> > >
> > > Dave
> > >
> > > -------------------------
> > > Dave Lindeman
> > > Lead Research Specialist
> > > 3M Company
> > > 3M Center 235-3F-08
> > > St. Paul, MN 55144
> > > 651-733-6383
> > >
> > >
> > > Jawad wrote:
> > > >
> > > >
> > > > Hi;
> > > >
> > > > I am facing a little difficulty in defining the elasto-
plastic
> > > > material property in abaqus.
> > > >
> > > > The model is bilinear kinematic hardening model, in which i
need
> > to
> > > > define the yield stress and tangent modulus (slope of the
plastic
> > > > region).
> > > >
> > > > In abaqus there is an option
> > > > Create Material -> Mechanical -> Plasticity -> Plastic
> > > > Its requires Yield Stress and corresponding Yield Strain but
no
> > > > tangent modulus value. I dont have the value of plastic
strain.
> > > >
> > > > My other qs is how to define the elastic-perfectly plastic
> > material
> > > > property in abaqus.
> > > >
> > > > Thanks in advance....
> > > >
> > > > Regards
> > > > Jawad Qarni
> > > >
> > > >
> > >
> >
> >
>

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Alankar Alankar | 12 Oct 19:21 2008
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Re: How to define Elasto-Plastic material property....

For incorporating tangent modulus you might have to look into user
subroutines like UHARD or UMAT. UMAT is a high end subroutine and is not
straight forward to implement. UHARD is a simple subroutine and can be used
to implement simple models like power law hardening.
Alankar

On Sat, Oct 11, 2008 at 5:36 AM, Jawad <jawadqarni <at> yahoo.com> wrote:

> Hi;
>
> I am facing a little difficulty in defining the elasto-plastic
> material property in abaqus.
>
> The model is bilinear kinematic hardening model, in which i need to
> define the yield stress and tangent modulus (slope of the plastic
> region).
>
> In abaqus there is an option
> Create Material -> Mechanical -> Plasticity -> Plastic
> Its requires Yield Stress and corresponding Yield Strain but no
> tangent modulus value. I dont have the value of plastic strain.
>
> My other qs is how to define the elastic-perfectly plastic material
> property in abaqus.
>
> Thanks in advance....
>
> Regards
> Jawad Qarni
>
>
>

--
Alankar
Ph.D. Student - Mechanical Engineering
School of Mechanical and Materials Engineering
Washington State University, Pullman
WA 99164-2920
USA

[Non-text portions of this message have been removed]

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sridharan.venkataramanan | 13 Oct 05:48 2008

RE: How to define Elasto-Plastic material property....

There is no ETAN option (like in LS-Dyna) inside abaqus. You need to
calculate few points beyond your yield point based on the slope and
input via *plastic. Do make sure that you cover the entire plastic
strain range expected. Otherwise abaqus would assume perfect-plasticity
beyond the last point.




Regards,
Sridharan

________________________________

From: Abaqus <at> yahoogroups.com [mailto:Abaqus <at> yahoogroups.com] On Behalf
Of Jawad
Sent: Saturday, October 11, 2008 6:07 PM
To: Abaqus <at> yahoogroups.com
Subject: [Abaqus] How to define Elasto-Plastic material property....

Hi;

I am facing a little difficulty in defining the elasto-plastic
material property in abaqus.

The model is bilinear kinematic hardening model, in which i need to
define the yield stress and tangent modulus (slope of the plastic
region).

In abaqus there is an option
Create Material -> Mechanical -> Plasticity -> Plastic
Its requires Yield Stress and corresponding Yield Strain but no
tangent modulus value. I dont have the value of plastic strain.

My other qs is how to define the elastic-perfectly plastic material
property in abaqus.

Thanks in advance....

Regards
Jawad Qarni

[Non-text portions of this message have been removed]

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Ibekwe Achinike | 22 Oct 19:38 2008
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Re: How to define Elasto-Plastic material property....

In addition, to completely define Elastic-perfect plasticity, add any other abitrary strain value for the same yield stress value. These two pairs is enough to completely define the required phenomenon.

Rgds,
Achinike
Newcastle University

________________________________
From: Dave Lindeman <ddlindeman <at> mmm.com>
To: Abaqus <at> yahoogroups.com
Sent: Monday, October 13, 2008 3:23:19 PM
Subject: Re: [Abaqus] How to define Elasto-Plastic material property....

You'll need to calculate the plastic strains by subtracting out the
elastic strain at each point on your stress-strain curve -- see the
Materials->Overview ->Inelastic Behavior section of the Materials part of
the User's Manual (19.1.1 in the 6.8 documentation) .

For an elastic-perfectly plastic material you simply need to define the
yield stress (which occurs at zero plastic strain):

*PLASTIC
yield stress,0.0

Regards,

Dave

------------ --------- ----
Dave Lindeman
Lead Research Specialist
3M Company
3M Center 235-3F-08
St. Paul, MN 55144
651-733-6383

Jawad wrote:
>
>
> Hi;
>
> I am facing a little difficulty in defining the elasto-plastic
> material property in abaqus.
>
> The model is bilinear kinematic hardening model, in which i need to
> define the yield stress and tangent modulus (slope of the plastic
> region).
>
> In abaqus there is an option
> Create Material -> Mechanical -> Plasticity -> Plastic
> Its requires Yield Stress and corresponding Yield Strain but no
> tangent modulus value. I dont have the value of plastic strain.
>
> My other qs is how to define the elastic-perfectly plastic material
> property in abaqus.
>
> Thanks in advance....
>
> Regards
> Jawad Qarni
>
>


[Non-text portions of this message have been removed]

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