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August 6, 2011, 16:31 |
polyflow
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#1 |
Senior Member
hamid
Join Date: Nov 2010
Posts: 185
Rep Power: 15 |
does anybody know how can i sue polyflow for the viscoelastic materials with "complex mudulus" properties?
thank you |
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September 7, 2011, 21:14 |
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#2 | |
New Member
Nicolas Clemeur
Join Date: Sep 2011
Posts: 7
Rep Power: 14 |
Quote:
I have written a software called RheoChart (google for it) that can help you in this procedure. |
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September 8, 2011, 03:05 |
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#3 | |
Senior Member
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Do you have any experience in using Cox-Merz rule for this purpose? I have some graphs for dynamic modulus in linear regime but I don't have any data in non-linear. As I know, we cannot use linear properties such as dynamic modules to find non-linear variables but you said that you used both linear and non linear properties simultaneously! would you elaborate it more? (is it physically correct?) I guess you're using linear and non-linear spectra as two parallel elements; right? PS: Thanks for your great software; when do you intend to release newer version? (is there any chance that creep properties are also included?) Bests,
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Amir |
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September 8, 2011, 03:16 |
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#4 | |
New Member
Nicolas Clemeur
Join Date: Sep 2011
Posts: 7
Rep Power: 14 |
Quote:
I am not sure I have said that. I said that in the first step you fit the parameter with the linear data and then you use non-linear data to fit non-linear parameter... |
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September 8, 2011, 03:59 |
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#5 |
Senior Member
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Dear Nicolas,
I apologize if I couldn't understand the point; I'm really new in viscoelastic modelling. As you know, I want to model a gel-like material in non-linear regime; because I don't have non linear data, I want to use cox-merz rule to obtain steady shear viscosity and finally as you've suggested before, I'll use one GNF mode and some non linear mode such as giesekus and I'll try to find variables of these modes with your software. Upon your experience, is this procedure correct? As you see, I don't use linear data directly. would you please elaborate your procedure in this example? PS: Thanks for your great software; when do you intend to release newer version? (is there any chance that creep properties are also included?) Bests,
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Amir |
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September 8, 2011, 06:55 |
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#6 | |
New Member
Nicolas Clemeur
Join Date: Sep 2011
Posts: 7
Rep Power: 14 |
Quote:
Thank you! There should be a release reasonnably soon (I can't really commit to a date, but I think one or 2 months is probably reasonnable.) I am actually working at implementing the creep kinematic in shear flow. |
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September 8, 2011, 08:20 |
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#7 | ||
Senior Member
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Now it's clear that G and should be set by linear data and with non linear one. I think that in student license there shouldn't be any restriction over number of modes, so I will increase mode numbers gradually in order to achieve best fitting. Thanks again,
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Amir |
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September 8, 2011, 08:30 |
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#8 | ||
New Member
Nicolas Clemeur
Join Date: Sep 2011
Posts: 7
Rep Power: 14 |
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Cheers Nicolas |
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September 8, 2011, 08:45 |
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#9 | ||
Senior Member
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Quote:
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Bests,
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Amir |
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September 8, 2011, 20:07 |
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#10 | |
New Member
Nicolas Clemeur
Join Date: Sep 2011
Posts: 7
Rep Power: 14 |
Quote:
http://powerlab.fsb.hr/ped/kturbo/Op...cFluidFoam.pdf There is no mention of a solvent viscosity there... Anyway, I am not the best person to answer that question. Cheers Nicolas |
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September 9, 2011, 02:12 |
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#11 | |
Senior Member
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Thanks for your time. About DCPP model you have mentioned, I don't agree with you; in page 16, polymer shear stress is computed by usiig parameters of this model and after summing these stresses, DEVSS method is used in page 18; note that solvent viscosity is in left hand side of this equation: It's worth to note that virtual function is used for evaluating shear stress in OpenFOAM, so the procedure of computing stress is same for all models, just stress formulations change. Here, because I know that the solvent is water, I'll introduce one constant viscosity mode and hold its value during fitting in your software. Bests,
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Amir |
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September 9, 2011, 02:24 |
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#12 |
New Member
Nicolas Clemeur
Join Date: Sep 2011
Posts: 7
Rep Power: 14 |
Quote:
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September 9, 2011, 02:44 |
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#13 | |
Senior Member
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Quote:
So it seems reasonable that we consider solvent viscosity as one or more separate modes and the formulation won't change. It's a great flexibility of your software which can handle both.(with or without solvent mode) As you said, I think also that this separation in considered to improve stability. But in many tutorials, solvent viscosity is considered. Bests,
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Amir Last edited by Amir; September 11, 2011 at 13:14. |
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