zero Force everywhere!!

[ziyad]

Hi all,
I had recieved following warrning when modeling load test on board pile. Has anyone an idea what does this mean. Attached inp.file.

regards
Ziyad

warrning:"There is zero FORCE everywhere in the model based on the default criterion. please check the value of the average FORCE during the current iteration to verify that the FORCE is small enough to be treated as zero. if not, please use the solution controls to reset the criterion for zero FORCE."Load-test.inp

[srinivas srinivas-2]

hello ziyad,

    I didn't understood your problem, your inp file is good its an error free file. you can run it successfully. Iam using ABQ-6.8-1.
 I found no errors.
--- In Abaqus@..., ziyad <ziyad02@...> wrote:

>
>
> Hi all,
> I had recieved following warrning when modeling load test on board pile. Has
> anyone an idea what does this mean. Attached inp.file.
>
> regards
> Ziyad
>
> warrning:"There is zero FORCE everywhere in the model based on the default
> criterion. please check the value of the average FORCE during the current
> iteration to verify that the FORCE is small enough to be treated as zero. if
> not, please use the solution controls to reset the criterion for zero
> FORCE." http://www.nabble.com/file/p24147811/Load-test.inp Load-test.inp
> --
> View this message in context: http://www.nabble.com/zero-Force-everywhere%21%21-tp24147811p24147811.html
> Sent from the Abaqus Users mailing list archive at Nabble.com.
>

[yowasi]

You might want to recheck your units.

Also, your entries for loads are expanded to, for example, "e+06" which I assume would be newtons. This expansion makes your numbers very large. If the calculation involves inverting at some point, you are bound to end up with very tiny numbers, which could easily be declared to be zero during computation!

Regards,
Robert

--- In Abaqus@..., ziyad <ziyad02@...> wrote:

>
>
> Hi all,
> I had recieved following warrning when modeling load test on board pile. Has
> anyone an idea what does this mean. Attached inp.file.
>
> regards
> Ziyad
>
> warrning:"There is zero FORCE everywhere in the model based on the default
> criterion. please check the value of the average FORCE during the current
> iteration to verify that the FORCE is small enough to be treated as zero. if
> not, please use the solution controls to reset the criterion for zero
> FORCE." http://www.nabble.com/file/p24147811/Load-test.inp Load-test.inp
> --
> View this message in context: http://www.nabble.com/zero-Force-everywhere%21%21-tp24147811p24147811.html
> Sent from the Abaqus Users mailing list archive at Nabble.com.
>

[steve manifold]

 

So if you invert 1e+06 you get 1e-06.  This is too small for modern
computers?

 

 

From: Abaqus@... [mailto:Abaqus@...] On Behalf Of
krobkrobkrob
Sent: Thursday, June 25, 2009 7:33 PM
To: Abaqus@...
Subject: [Abaqus] Re: zero Force everywhere!!

 






You might want to recheck your units.

Also, your entries for loads are expanded to, for example, "e+06" which I
assume would be newtons. This expansion makes your numbers very large. If
the calculation involves inverting at some point, you are bound to end up
with very tiny numbers, which could easily be declared to be zero during
computation!

Regards,
Robert

--- In Abaqus@... <mailto:Abaqus%40yahoogroups.com> , ziyad
<ziyad02@...> wrote:
>
>
> Hi all,
> I had recieved following warrning when modeling load test on board pile.
Has
> anyone an idea what does this mean. Attached inp.file.
>
> regards
> Ziyad
>
> warrning:"There is zero FORCE everywhere in the model based on the default
> criterion. please check the value of the average FORCE during the current
> iteration to verify that the FORCE is small enough to be treated as zero.
if
> not, please use the solution controls to reset the criterion for zero
> FORCE." http://www.nabble.com/file/p24147811/Load-test.inp Load-test.inp
> --
> View this message in context:
http://www.nabble.com/zero-Force-everywhere%21%21-tp24147811p24147811.html
> Sent from the Abaqus Users mailing list archive at Nabble.com.
>





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

[ziyad]

Hi Robert,
yes, I am using the SI units (N, Pa, Kg,....), for example pressure from 3.5 MN acting on area of 1.37 m2 I defined as 2.53467E+006.
Do u think I should use another unit system?

Regards
Ziyad

yowasi wrote:

You might want to recheck your units.

Also, your entries for loads are expanded to, for example, "e+06" which I assume would be newtons. This expansion makes your numbers very large. If the calculation involves inverting at some point, you are bound to end up with very tiny numbers, which could easily be declared to be zero during computation!

Regards,
Robert

--- In [e-mail], ziyad <ziyad02@...> wrote:
>
>
> Hi all,
> I had recieved following warrning when modeling load test on board pile. Has
> anyone an idea what does this mean. Attached inp.file.
>
> regards
> Ziyad
>
> warrning:"There is zero FORCE everywhere in the model based on the default
> criterion. please check the value of the average FORCE during the current
> iteration to verify that the FORCE is small enough to be treated as zero. if
> not, please use the solution controls to reset the criterion for zero
> FORCE." http://www.nabble.com/file/p24147811/Load-test.inp Load-test.inp
> --
> View this message in context: http://www.nabble.com/zero-Force-everywhere%21%21-tp24147811p24147811.html
> Sent from the Abaqus Users mailing list archive at Nabble.com.
>

[yowasi]

There is a good reason why I used "could" and not "will". The same reason underlies the mention of the need to recheck units. Play with a few numbers where units are mixed (which is a very easy mistake to make) and where numbers could (as a result) differ by such orders of magnitude.

Regards,
Robert

--- In Abaqus@..., "Steve Manifold" <s.manifold@...> wrote:

>
>  
>
> So if you invert 1e+06 you get 1e-06.  This is too small for modern
> computers?
>
>  
>
>  
>
> From: Abaqus@... [mailto:Abaqus@...] On Behalf Of
> krobkrobkrob
> Sent: Thursday, June 25, 2009 7:33 PM
> To: Abaqus@...
> Subject: [Abaqus] Re: zero Force everywhere!!
>
>  
>
>
>
>
>
>
> You might want to recheck your units.
>
> Also, your entries for loads are expanded to, for example, "e+06" which I
> assume would be newtons. This expansion makes your numbers very large. If
> the calculation involves inverting at some point, you are bound to end up
> with very tiny numbers, which could easily be declared to be zero during
> computation!
>
> Regards,
> Robert
>
> --- In Abaqus@... <mailto:Abaqus%40yahoogroups.com> , ziyad
> <ziyad02@> wrote:
> >
> >
> > Hi all,
> > I had recieved following warrning when modeling load test on board pile.
> Has
> > anyone an idea what does this mean. Attached inp.file.
> >
> > regards
> > Ziyad
> >
> > warrning:"There is zero FORCE everywhere in the model based on the default
> > criterion. please check the value of the average FORCE during the current
> > iteration to verify that the FORCE is small enough to be treated as zero.
> if
> > not, please use the solution controls to reset the criterion for zero
> > FORCE." http://www.nabble.com/file/p24147811/Load-test.inp Load-test.inp
> > --
> > View this message in context:
> http://www.nabble.com/zero-Force-everywhere%21%21-tp24147811p24147811.html
> > Sent from the Abaqus Users mailing list archive at Nabble.com.
> >
>
>
>
>
>
> [Non-text portions of this message have been removed]
>

[aruk77500]

hello group,

I need to take idea of you about a problem.

I want to make a stress relaxation analysis of PA6. Let's say a polymer rod is pretensioned by applyling a strain. And then, I want to calculate the time required for the stress to come below a certain limit under this constant strain.

What kind of analysis should I carry? A general static step to apply the pretension and then what? a visco analysis? What kind of material behaviour should I use for such a problem? What are the outputs in Abaqus I should check? Is there a smiler problem in Abaqus documentation?

Thank you very much for your taking the time.

fatih

--- In Abaqus@..., "Steve Manifold" <s.manifold@...> wrote:

>
>  
>
> So if you invert 1e+06 you get 1e-06.  This is too small for modern
> computers?
>
>  
>
>  
>
> From: Abaqus@... [mailto:Abaqus@...] On Behalf Of
> krobkrobkrob
> Sent: Thursday, June 25, 2009 7:33 PM
> To: Abaqus@...
> Subject: [Abaqus] Re: zero Force everywhere!!
>
>  
>
>
>
>
>
>
> You might want to recheck your units.
>
> Also, your entries for loads are expanded to, for example, "e+06" which I
> assume would be newtons. This expansion makes your numbers very large. If
> the calculation involves inverting at some point, you are bound to end up
> with very tiny numbers, which could easily be declared to be zero during
> computation!
>
> Regards,
> Robert
>
> --- In Abaqus@... <mailto:Abaqus%40yahoogroups.com> , ziyad
> <ziyad02@> wrote:
> >
> >
> > Hi all,
> > I had recieved following warrning when modeling load test on board pile.
> Has
> > anyone an idea what does this mean. Attached inp.file.
> >
> > regards
> > Ziyad
> >
> > warrning:"There is zero FORCE everywhere in the model based on the default
> > criterion. please check the value of the average FORCE during the current
> > iteration to verify that the FORCE is small enough to be treated as zero.
> if
> > not, please use the solution controls to reset the criterion for zero
> > FORCE." http://www.nabble.com/file/p24147811/Load-test.inp Load-test.inp
> > --
> > View this message in context:
> http://www.nabble.com/zero-Force-everywhere%21%21-tp24147811p24147811.html
> > Sent from the Abaqus Users mailing list archive at Nabble.com.
> >
>
>
>
>
>
> [Non-text portions of this message have been removed]
>

[Alberto Echeverria]

Dear Fatih,

 

I think you should read about how to do a creep analysis. If you apply a
creep type law (There are different models depending on the creep mechanism,
Norton , time hardening, strain hardening…) for your material under
prescribed strain conditions you will see that elastic strain will transform
into creep strain and this way the stress (dependent on the elastic strain)
will decrease.

 

I remember that you ought to use *Visco kind of analysis.

I cannot remember if there are examples, please check the documentation.

 

Kind regards,

 

Alberto

 

 

De: Abaqus@... [mailto:Abaqus@...] En nombre de
aruk77500
Enviado el: miércoles, 01 de julio de 2009 13:20
Para: Abaqus@...
Asunto: [Abaqus] stress relaxation problem...

 






hello group,

I need to take idea of you about a problem.

I want to make a stress relaxation analysis of PA6. Let's say a polymer rod
is pretensioned by applyling a strain. And then, I want to calculate the
time required for the stress to come below a certain limit under this
constant strain.

What kind of analysis should I carry? A general static step to apply the
pretension and then what? a visco analysis? What kind of material behaviour
should I use for such a problem? What are the outputs in Abaqus I should
check? Is there a smiler problem in Abaqus documentation?

Thank you very much for your taking the time.

fatih

--- In Abaqus@... <mailto:Abaqus%40yahoogroups.com> , "Steve
Manifold" <s.manifold@...> wrote:

>
>
>
> So if you invert 1e+06 you get 1e-06. This is too small for modern
> computers?
>
>
>
>
>
> From: Abaqus@... <mailto:Abaqus%40yahoogroups.com>

[mailto:Abaqus@... <mailto:Abaqus%40yahoogroups.com> ] On Behalf
Of

> krobkrobkrob
> Sent: Thursday, June 25, 2009 7:33 PM
> To: Abaqus@... <mailto:Abaqus%40yahoogroups.com>
> Subject: [Abaqus] Re: zero Force everywhere!!
>
>
>
>
>
>
>
>
> You might want to recheck your units.
>
> Also, your entries for loads are expanded to, for example, "e+06" which I
> assume would be newtons. This expansion makes your numbers very large. If
> the calculation involves inverting at some point, you are bound to end up
> with very tiny numbers, which could easily be declared to be zero during
> computation!
>
> Regards,
> Robert
>
> --- In Abaqus@... <mailto:Abaqus%40yahoogroups.com>

<mailto:Abaqus%40yahoogroups.com> , ziyad

> <ziyad02@> wrote:
> >
> >
> > Hi all,
> > I had recieved following warrning when modeling load test on board pile.
> Has
> > anyone an idea what does this mean. Attached inp.file.
> >
> > regards
> > Ziyad
> >
> > warrning:"There is zero FORCE everywhere in the model based on the

default
> > criterion. please check the value of the average FORCE during the
current
> > iteration to verify that the FORCE is small enough to be treated as
zero.
> if
> > not, please use the solution controls to reset the criterion for zero
> > FORCE." http://www.nabble.com/file/p24147811/Load-test.inp Load-test.inp

> > --
> > View this message in context:
> http://www.nabble.com/zero-Force-everywhere%21%21-tp24147811p24147811.html
> > Sent from the Abaqus Users mailing list archive at Nabble.com.
> >
>
>
>
>
>
> [Non-text portions of this message have been removed]
>

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

[yowasi]

Hi Ziyad,

Are you still getting the same warning message?

It is not a question of the units system but one of consistency. The SI system is king! Use whichever system you wish as long as you're consistent. If, for example, you are using Pa and m, you do have to check that you have not written mm somewhere when you really meant m. Similarly if you had used MPa and mm, you would have to check that you had not written m when you meant mm etc etc.

If all that is checked and fine, then you have to look elsewhere for a possible cause of the warning message you got.

Hope that is useful.

Regards,
Robert

--- In Abaqus@..., ziyad <ziyad02@...> wrote:

>
>
> Hi Robert,
> yes, I am using the SI units (N, Pa, Kg,....), for example pressure from 3.5
> MN acting on area of 1.37 m2 I defined as 2.53467E+006.
> Do u think I should use another unit system?
>
> Regards
> Ziyad
>
>
> yowasi wrote:
> >
> > You might want to recheck your units.
> >
> > Also, your entries for loads are expanded to, for example, "e+06" which I
> > assume would be newtons. This expansion makes your numbers very large. If
> > the calculation involves inverting at some point, you are bound to end up
> > with very tiny numbers, which could easily be declared to be zero during
> > computation!
> >
> > Regards,
> > Robert
> >
> > --- In Abaqus@..., ziyad <ziyad02@> wrote:
> >>
> >>
> >> Hi all,
> >> I had recieved following warrning when modeling load test on board pile.
> >> Has
> >> anyone an idea what does this mean. Attached inp.file.
> >>
> >> regards
> >> Ziyad
> >>
> >> warrning:"There is zero FORCE everywhere in the model based on the
> >> default
> >> criterion. please check the value of the average FORCE during the current
> >> iteration to verify that the FORCE is small enough to be treated as zero.
> >> if
> >> not, please use the solution controls to reset the criterion for zero
> >> FORCE." http://www.nabble.com/file/p24147811/Load-test.inp Load-test.inp
> >> --
> >> View this message in context:
> >> http://www.nabble.com/zero-Force-everywhere%21%21-tp24147811p24147811.html
> >> Sent from the Abaqus Users mailing list archive at Nabble.com.
> >>
> >
> >
> >
> >
>
> --
> View this message in context: http://www.nabble.com/zero-Force-everywhere%21%21-tp24147811p24259352.html
> Sent from the Abaqus Users mailing list archive at Nabble.com.
>