« Return to Thread: zero Force everywhere!!
stress relaxation problem...
by aruk77500
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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]
>
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]
>
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