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Elastic strain energy

Posted 18 août 2014, 08:14 UTC−4 Results & Visualization, Structural Mechanics Version 4.3b 8 Replies

Alexander Côté
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Is there a way to output the elastic strain energy (and not its density at certain points), as a number for my whole structure? i.e. the half of the volume integral of (stress x strain)?

Thank you
8 Replies Last Post 10 sept. 2014, 12:02 UTC−4
Frank van Gool COMSOL Employee

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Posted: 1 decade ago 18 août 2014, 08:47 UTC−4
Hi Alexander,

Do you mean the total elastic strain energy? This is called "solid.Ws_tot" in COMSOL and can be accessed under global evaluation for instance.
Note that you can also just create integrals manually under component>>definitions>>component couplings.

Best regards,
Frank
Hi Alexander, Do you mean the total elastic strain energy? This is called "solid.Ws_tot" in COMSOL and can be accessed under global evaluation for instance. Note that you can also just create integrals manually under component>>definitions>>component couplings. Best regards, Frank
Alexander Côté
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Posted: 1 decade ago 18 août 2014, 12:54 UTC−4
Hello Frank,

I suspect that's exactly what I want, but I can't find how to access solid.Ws_tot. Accessing just solid.Ws is no problem, but I cannot find where to input the "tot" part, it doesn't recognise it. I have version 4.2a, was it introduced later maybe?

Thanks very much for your help,
Alex
Hello Frank, I suspect that's exactly what I want, but I can't find how to access solid.Ws_tot. Accessing just solid.Ws is no problem, but I cannot find where to input the "tot" part, it doesn't recognise it. I have version 4.2a, was it introduced later maybe? Thanks very much for your help, Alex
Frank van Gool COMSOL Employee

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Posted: 1 decade ago 19 août 2014, 05:21 UTC−4
Dear Alexander,

that explains it. In 4.2a that was not yet introduced.
You can however take the volume integral over the whole domain, of solid.Ws and this gives you the same result as solid.Ws_tot.

best regards,
Frank
Dear Alexander, that explains it. In 4.2a that was not yet introduced. You can however take the volume integral over the whole domain, of solid.Ws and this gives you the same result as solid.Ws_tot. best regards, Frank
Alexander Côté
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Posted: 1 decade ago 19 août 2014, 06:21 UTC−4
Hi Frank,

Great, that clears it up, I have to upgrade... just to make sure, can I take the volume integral by starting an integration definition (intop1) in the model, and then doing intop1(solid.Ws)? Just asking because this gives a strange tiny number, far from what I expected...

Thanks again,
Alex
Hi Frank, Great, that clears it up, I have to upgrade... just to make sure, can I take the volume integral by starting an integration definition (intop1) in the model, and then doing intop1(solid.Ws)? Just asking because this gives a strange tiny number, far from what I expected... Thanks again, Alex
Frank van Gool COMSOL Employee

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Posted: 1 decade ago 19 août 2014, 06:42 UTC−4
Hi Alex,

Make sure that all the domains are included in the intop1.
Also, perhaps you can share the result that you have now, and the result what you expect (and why). Perhaps we can find out where this is coming from.

best regards,
Frank


Hi Alex, Make sure that all the domains are included in the intop1. Also, perhaps you can share the result that you have now, and the result what you expect (and why). Perhaps we can find out where this is coming from. best regards, Frank
Alexander Côté
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Posted: 1 decade ago 19 août 2014, 08:11 UTC−4
Ok I found the problem, it was a stray input value I forgot to change. It seems to work now. Thank you very much for your help!
Ok I found the problem, it was a stray input value I forgot to change. It seems to work now. Thank you very much for your help!
Balazs Fekete
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Posted: 1 decade ago 10 sept. 2014, 08:58 UTC−4
Dear Frank,

I have a question concerning to the strain density. I have an elastoplastic analysis and I want to investigate the the total (included plastic) strain energy at a certain point of the structure. I found only the elastic strain energy density option, however, I carried out my calculation with plastic material model.

Please, could you inform me how can i manage the plastic (or total) strain energy?
Thank you in advance!
BR
Balazs
Dear Frank, I have a question concerning to the strain density. I have an elastoplastic analysis and I want to investigate the the total (included plastic) strain energy at a certain point of the structure. I found only the elastic strain energy density option, however, I carried out my calculation with plastic material model. Please, could you inform me how can i manage the plastic (or total) strain energy? Thank you in advance! BR Balazs
Josh Thomas Certified Consultant
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Posted: 1 decade ago 10 sept. 2014, 12:02 UTC−4
Hi-

This functionality is available in version 4.4. To calculate plastic dissipation, you will first need to enable "Advanced Physics Options" from the "show" icon in the "model builder". Then, navigate to the branch "Linear elastic Material" in "solid Mechanics" physics interface and enable the "calculate dissipated energy" option in the settings window.

To evaluate the plastic dissipation, for example, you can right click on "Derived values" and choose "Global Evaluation" and then select "Total Plastic dissipation" from the "replace expression" menu.

--
Best regards,
Josh Thomas
AltaSim Technologies
Hi- This functionality is available in version 4.4. To calculate plastic dissipation, you will first need to enable "Advanced Physics Options" from the "show" icon in the "model builder". Then, navigate to the branch "Linear elastic Material" in "solid Mechanics" physics interface and enable the "calculate dissipated energy" option in the settings window. To evaluate the plastic dissipation, for example, you can right click on "Derived values" and choose "Global Evaluation" and then select "Total Plastic dissipation" from the "replace expression" menu. -- Best regards, Josh Thomas AltaSim Technologies

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