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Converting ABAQUS vumat into ANSYS usermaterial  


denjr
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Hello,

I am interested in converting an existing ABAQUS vumat into an ANSYS usermaterial. Has any one of you done that or is that feasible ?

Actually I started to look for the differences, then :

1- All variables are named differently despite of some intuitive similarities right ?

2- Admitting that I have changed all things with its appropriate name are there still fundamental incompatibilities for a direct use in ANSYS FE-code?

3- LAST : does ANSYS need for a specific Fortran compiler as ABAQUS does ?

My current vumat concerns plasticity of crystals, for studying the fatigue of polycristallin metallic materials. All responses are welcome !

Mandriam

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Jorgen
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I have written many user-material models for both Abaqus and ANSYS, so it is certainly feasible.

The main challenge is that an ANSYS usermaterial requires a tangent stiffness matrix (Jacobian), which is not used in a VUMAT.
So you have to code that part...

-Jorgen

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denjr
Posts: 6
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Joined: 9 years ago

Jorgen, thank you much !

Though, I thought the tangent stiffness matrix was the function of ddsdde tensor ...

In my case I use ddsdde as an effective elastic stiffness matrix (calculated for each block and at all time increment). That permits me to output my consistent tangent ...

So what does that Jacobian (in ANSYS user-mat) refer to ... ? Sorry I may be far from understanding the point :confused:.

Mandriam

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Jorgen
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Jacobian = Tangent stiffness

,)

-Jorgen

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