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Hidroxid's picture

XFEM crack under compression.

Hi all,

 

I am doing crack modelling (XFEM) under moving compression and traction loading in Abaqus but I get warning regarding the crack under compression load as follows:

"THE LOADING CONDITION MIGHT MAKE MAIN CRACK UNDER COMPRESSION AT  NSET "X" THE CRACK PROPAGATION DIRECTION CANNOT BE PREDICTED. A VALUE OF ZERO IS PROVIDED FOR IT."

Anyone facing the same issue?

Kind regards,

Omid

Hidroxid's picture

Applying a moving pressure and traction in Abaqus

Hello all,

I have applied a moving ellyptical hertzian pressure load on a surface using a DLOAD which works, but I also need the traction load which is the multiplication of this pressure with a friction coeffcient.

Does anybody have any clue how to do it? Directly through abaqus or inside the same DLOAD?

 

Kind regards,

Omid

Hidroxid's picture

Huang's Crystal Plasticity UMAT taking into account Bauschinger effect for cyclic loading (kinematic hardening)

Hello,  

In the Crystal Plascticity UMAT model for Abaqus (by prof. Hunag) the Bauschinger effect which is important for cyclic loading, is not considered.  

Is there any edited version of this UMAT considering this effect for cyclic loading (by also considering kinematic hardening)?

 

Kind regards,

Omid 

Hidroxid's picture

Crystal Plasticity User Material for Abaqus incorporating twinning

Hello,

The most famous user material (UMAT) for Abaqus is the UMAT from prof. Hunag. But the twinning is not implemented in it.

Does anyone know if theere is any other UMATs which the twinning effect (plastic deformation due to twinning) is implemented?

 

Kind regards,

Omid

Hidroxid's picture

Pressure load on element-based surface? or converting element-based surface to geometric surface to apply pressure in abaqus?

I would like to use pressure load on a element based surface, in Abaqus. This surface is a combination of small surface elements (in an orphan mesh). But to apply pressure load you need to have a geometic surface.

How can I do this? Is it possible to make a geometric surface using this element-based surface?

 

Regards,

Omid

 

Hidroxid's picture

Assigning crystal plasticity material constants for one crystal with more than one element (default of Dr Huangs model)

Hi!

 

I am just a beginner in Abaqus UMAT and I have started working with Dr Huang's crystal plasticity UMAT in Abaqus.

When I am assigning one material constants for one element crystal it works but when I try to assign it to more than one element for one crystal (for example group of elements with same grain orientation) it give me error code 144.

Can anybody explain me the reason?

 

 

Thanks in advance,

Kind regards,

Omid

 

Hidroxid's picture

ainsotrpic plasticity in Abaqus

Hello

 

Does anybody know how to input ainsotrpic plasticity in Abaqus?

I have an orthogonal elastoc plastic material and to input elastic properties I use engineering constants but to input orthogonal plasticity (not for all components)  I have no clue.

 

Thnaks in advance,

Hidroxid's picture

problem with reduced quadratic elements (C3D20R) while used in a node to surface contact discretization

Hello,

Can anyone explain to me what is the problem with reduced quadratic elements (C3D20R) while used in a node to surface contact discretization?

I am using a traction-seperation formulation cohesive surface and for that I can only define node to surface contact. In this case element types of C3D8I and C3D20 work but C3D20R does not work! (I am using Abaqus)

Thanks a lot,

Hidroxid's picture

Reading abaqus field output data using python scripts in an especial coordinate (x,y,z location) and not node/element set

Hello everyone,

I am using python scripts to extract the field output (displacements) in a nodeset (which was defined in the model) and it does not seem that difficult but I have a question regarding reading output data for a especial coordinate (x,y,z location) and not the node label since when you change the discretization you lose the previous node labels. Does anyone have any idea how to do so?

Hidroxid's picture

loop inside a .psf file (parametric study file) in abaqus to get field variable output

Dear all,

Does anybody how we can put a loop (for example while loop) inside a .psf (parametric study) file in abaqus?

For example a loop on all the increments we want to get a field variable output. Take a look at the following code:

...

Hidroxid's picture

Sequential change of some parts in a Abaqus input file and running the code for each.

Hello everyone,

I am trying to run some simulation in abaqus, I need to change some input variables and run the code for new values and this should be an automatic process not by hand every time.

Now I want to check if there is any way to change some parts in a abaqus .inp (input) file (say the Forces or other BC's) and execute the code again in abaqus and store the results of each simulation.

 

Thanks in advace,

Hidroxid's picture

sequential Abaqus input change

Hello,

 I need to write a python script that changes the inputs in my MDB file and then runs the abaqus code and gets the output and then goes on with another sets of inputs.

Since I am quite a beginner in abaqus-python scripting, does anyone has any clue how to do this automatically, I mean not changing the inputs in every run manually.

Thanks,

Omid

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