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UMAT

Two UMATS in one Subroutine

Submitted by ABAqirl on
research
UMAT
ABAUS

Dear All,

I have the problem. i created very simple example with two elements. To one element i prescribed the behaviour Mat1, to another element Mat2. I tried to use two different UMATS for this two elements.

I created Subroutine Myname.f, in which i use CMNAME if (CNMAME.EQ.'MAT1) THEN

CALl UMAT_1()

ELSE IF (CMNAME.EQ.'MAT2) THEN

CALL UMAT_2()

END IF

Then i put two UMATS in the same SUBROUTINES ,

But as a result the program gives MISTAKE , it says that The UMAT doesn't exist

What is the mistake?

Look for free-code UMAT on polymer viscoplasticity model of M.C. Boyce

Submitted by Liu Jinxing on
software
polymer
UMAT
Boyce

I just attended USNCCM11, and heard from a presentation that there should be free code for polymer viscoplasticity model from M.C. Boyce.Unfortunately, I googled from half an hour and dowloaded nothing this afternoon. Can anybody give more info ?

Thanks in advance !

Combining UMAT with XFEM

Submitted by Panos Efthymiadis on
research
xfem
Crystal plasticity
UMAT

Hi all,

I 'd like to ask whether anyone has applied XFEM for a user-material (UMAT). What is the process to do that? Could anyone provide some advice, documentation or guidelines?



All the best,

            
Panos



p.s. I 've heard that a UEL code is needed to couple XFEM with UMAT.

Crystal Plasticity Modelling

Submitted by Panos Efthymiadis on
research
UMAT

Hi all,

     I want to set up a critical shear strain - normal stress criterion, in UMAT by prof. Huang. For the strains it is easy to get a critical strain along a slip plane; but for the stresses the notation is quite weird. It is not the same! See below:

C       Array STATEV:

C       3*NSLPTL+1 - 6*NSLPTL  :  current components of normals to slip

Damage modeling with UMAT

Submitted by Panos Efthymiadis on
UMAT

Dear all,

      I am using a Abaqus modeller with fortran subroutines. I have written a UMAT subroutine and now want to apply some damage initiation-evolution criteria. But I get the following error: a damage initiation property was used with a user material.

I wanted to apply the criteria externally from the subroutine.. How can I go through with this problem? I tried different criteria (stress and strain based) to check if it is a matter of the output variables... No result..

How can I model the progressive damage of composite materials

Submitted by Jameswei on
software
UMAT
progressive damage
USDFLS

Recently, I indulged myself into the progressive damage simulation of composite materials. I firstly used the USDFLS to create several fields to define certain kinds of damage, such as fiber crack, matrix crack, shear damage and delamination. One curious thing that I experienced into this is that ABAQUS/Standard informed me that "Stiffness defined by engineering constants is not physically reasonable. Check choice of poisson's ratios". I checked the data and changed some to comply with the rules of the transversely isotropic materials and the program proceeded. 

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