[Abaqus] extraction of strain energy release rates using cohesive zone modeling

[Sindhu Kashyap [e-mail] [Abaqus]]

Dear all,
I am a student carrying out my Master's project. I want to perform a
comparative study of strain energy release rates for a delamination of
double cantilever beam using Virtual crack closure technique(VCCT) and
Cohesive zone modeling(CZM). I could extract the values of strain energy
release rates using VCCT directly in the visualization module. But i am not
able to directly extract the values of strain energy release rates using
Cohesive modeling method.
i have tried using both cohesive surface contact and cohesive element
contact. But i am not able to get the values of strain energy release rates
using any of the two methods of cohesive zone modeling.
Is there any way to extract strain energy release rates using cohesive
modeling approach?
Thanks in advance for your help,
SINDHU BR

[Martin Baeker [e-mail] [Abaqus]]

You can simply use the abaqus history variables like ALLIE if you only
need the strain energy in the whole model.

Or you can write the strain energy in each element as output to the odb.

Post by Sindhu Kashyap ***@gmail.com [Abaqus]
Dear all,
I am a student carrying out my Master's project. I want to perform a
comparative study of strain energy release rates for a delamination of
double cantilever beam using Virtual crack closure technique(VCCT) and
Cohesive zone modeling(CZM). I could extract the values of strain energy
release rates using VCCT directly in the visualization module. But i am not
able to directly extract the values of strain energy release rates using
Cohesive modeling method.
i have tried using both cohesive surface contact and cohesive element
contact. But i am not able to get the values of strain energy release rates
using any of the two methods of cohesive zone modeling.
Is there any way to extract strain energy release rates using cohesive
modeling approach?
Thanks in advance for your help,
SINDHU BR

Priv...-Doz. Dr. Martin BÀker
Institut fÃŒr Werkstoffe
Technische UniversitÀt Braunschweig
Langer Kamp 8
38106 Braunschweig
Germany
Tel.: [phone]
Fax [phone]
e-mail <***@tu-bs.de>
http://www.tu-braunschweig.de/ifw/institut/mitarbeiter/baeker
http://www.scienceblogs.de/hier-wohnen-drachen

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

[Shreyas Joglekar [e-mail] [Abaqus]]

It should be the area under force displacement curve

As you load the double cantilever beam, the force will increase, reach a
peak, then degrade to zero. The degradation of cohesive surface from peak
to zero will be dictated by the energy release rate value that you input.
Abaqus will accurately show you the input energy release rate for pure mode
I and pure mode II. It might deviate for in between mode mixities depending
upon your modeling strategy.

[image: image.png]

[Sindhu Kashyap [e-mail] [Abaqus]]

Thank you.
But can we get the strain energy release rate at each nodal point like we
get in VCCT? I am doing a comparative study of two techniques, VCCT and
CZM of 3D composite DCB and a standard plate specimen . In VCCT i have
directly got the values of energy release rates in visualization tab with
field outputs ENERT and ENEER1,2 and 3 for each node. But when i call for
the same field output in CZM method the values of all energy release rates
are zero irrespective of the loads or displacements applied. So my question
is ,is there any way where we can get the values of energy release rate in
CZM similar to VCCT for each node?

Please let me know as i am stuck with the extraction of energy release rate
results since a long time.
Thanks in advance.

Post by Shreyas Joglekar ***@ncsu.edu [Abaqus]
It should be the area under force displacement curve
As you load the double cantilever beam, the force will increase, reach a
peak, then degrade to zero. The degradation of cohesive surface from peak
to zero will be dictated by the energy release rate value that you input.
Abaqus will accurately show you the input energy release rate for pure mode
I and pure mode II. It might deviate for in between mode mixities depending
upon your modeling strategy.
[image: image.png]
--
Shreyas Joglekar
[Non-text portions of this message have been removed]

[Martin Baeker [e-mail] [Abaqus]]

you can get energies and densities for elements with ELSE/ELSEDEN

Post by Sindhu Kashyap ***@gmail.com [Abaqus]
Thank you.
But can we get the strain energy release rate at each nodal point like we
get in VCCT? I am doing a comparative study of two techniques, VCCT and
CZM of 3D composite DCB and a standard plate specimen . In VCCT i have
directly got the values of energy release rates in visualization tab with
field outputs ENERT and ENEER1,2 and 3 for each node. But when i call for
the same field output in CZM method the values of all energy release rates
are zero irrespective of the loads or displacements applied. So my question
is ,is there any way where we can get the values of energy release rate in
CZM similar to VCCT for each node?
Please let me know as i am stuck with the extraction of energy release rate
results since a long time.
Thanks in advance.

Post by Shreyas Joglekar ***@ncsu.edu [Abaqus]
It should be the area under force displacement curve
As you load the double cantilever beam, the force will increase, reach a
peak, then degrade to zero. The degradation of cohesive surface from peak
to zero will be dictated by the energy release rate value that you input.
Abaqus will accurately show you the input energy release rate for pure mode
I and pure mode II. It might deviate for in between mode mixities depending
upon your modeling strategy.
[image: image.png]
--
Shreyas Joglekar
[Non-text portions of this message have been removed]

Priv.-Doz. Dr. Martin BÀker
Institut fÃŒr Werkstoffe
Technische UniversitÀt Braunschweig
Langer Kamp 8
38106 Braunschweig
Germany
Tel.: [phone]
Fax [phone]
e-mail <***@tu-bs.de>
http://www.tu-braunschweig.de/ifw/institut/mitarbeiter/baeker
http://www.scienceblogs.de/hier-wohnen-drachen

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