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USERMAT coding

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rak
Posts: 3
 rak
Topic starter
(@rak)
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Joined: 11 years ago

Hi,

I highly appreciate anyone who takes a look at my questions and responses them...

I am beginner in using UPFs. I have red UPFs manual and USERMAT3D subroutine.

first of all, Recently, i have written my desired user material subroutine, which contains stress update(3 mode is considered using RMA:apex return mapping, line return mapping and surface return mapping), and material constitutive matrix. Now, i want to know if there is any other variable , which should be calculated? (i mean: Should the value for epesq and the other materials presented in USERMAT3D be calculated and written?)

moreover, is not there any problem with using a significant number of subroutines, which are to be called in the main part of USERMAT3D?(I have previously heard about some problems about using multiple routines in an user-defined routine...).

above all, I am a bit confused about verification process for validating my code...in fact, I dont know how i can test my code...(I think, testing a single element for a linear elastic material which is recommended for verifying the linking and activating procedure can not efficiently evaluate the codes accuracy in the case of materials plastic behavior). Is there any useful and well-prepared procedure for verifying an user material code?

thanks a lot for paying attention to my questions and for any probable response.

With The Kindest and Warmest Regards, Hadi

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Jorgen
Posts: 3964
(@jorgen)
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Joined: 3 years ago

It sounds like you are making good progress. The ANSYS docs describe which parameters you need to return, check the manual again.

You can use any number of subroutine functions in your Fortran code - not a problem.

Validation is important but there is no universal strategy to follow.

-Jorgen

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rak
Posts: 3
 rak
Topic starter
(@rak)
New Member
Joined: 11 years ago

Thanks a lot for your response.

in the case of using a couple of routines in usermat: Indeed, I want to update my stress array from an initial value...using USTRESS routine with USERMAT is ok? or should another subroutine be considered?...

for another, Now, I want to compile and link my code. But, At First, I want to be sure of my linking and compiling procedures accuracy. Thus, I decided to compile and link a simple elastic USERMAT and compare its results with ANSYSs standard elastic material.

But, I have not any obvious strategy to compile and link it.

is there any step by step guide to link user-written codes? (The mentioned strategy in UPFs manual is significantly useful, but not sufficient.).

I will highly appreciate you for any guidance...

Again, Thank You a lot...

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Jorgen
Posts: 3964
(@jorgen)
Member
Joined: 3 years ago

ANSYS provides a recommended script for compiling user-subroutines. I dont recall at the moment the location where it is stored, but if you should find it if you search. I manually compile my ANSYS source files, but I dont recommend that unless you are a compiler/linker expert.

-Jorgen

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