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strain-displacement matrix

Hello everyone,

I have a basic question in ABAQUS. For developing a user element in ABAQUS, the strain-displacement tensor, or the so-called B-matrix, needs to be calculated in the UEL subroutine. Applying the B-matrix on the displacement vector gives rise to the strain vector. However, we know that there are more than one strain measure for corresponding, or in other words, different conjugate stress measures.

 What is here not clear for me is what type of strain tensor is calculated by applying B on the displacement vector: (eps=B.d) what is eps here?

Time Incerement Effect in Abaqus


I have written a user material for Abaqus to simulate the behavior of trabecular bone in large strain compression. The model undergoes elastic and plastic deformation. In the plastic regime, hardening and damage are growing depending on cumulated plastic strain.

Total or Updated Lagrange?

Hi Guys,

Would someone let me know if ABAQUS uses total Lagrange or updated Lagrange formulation to calculate the strain-displacement or the so-called B matrix (ref. K J Bathe finite element procedures chapter 6), or whether or not one can switch from total to updated Lagrange and vice versa in ABAQUS?



ABAQUS User Subroutine references

Dear iMechanica users,

If you are concerned with user subroutines in ABAQUS, the link below may be helpful:


Best, Hadi

Nonlocal Damage implementation using ABAQUS UEL

Hi everyone,

In order to simulate nonlocal damage in trabecular bone structures in
ABAQUS, I need to implement the constitutive laws into the user element
subroutine (UEL), since it is not possible to implement nonlocal FE in
UMAT, as far as I know!

I would be very much grateful if someone, who has experience in this
regard, esp how to implement 3D elements, e.g. C3D8, into a UEL code,
shares some knowledge.



UEL for 2 or 3D element types

Dear iMechanica users,

I would like to write a UEL for 2 or 3D element types used in large deformation, but, I really have little experience in it. Is there any UEL example apart from the simple 1D example in Abaqus manual and the complicated one written by Eugenio (XFEM)?



Reading elsets from UMAT in ABAQUS

Dear all,

I intend to read the element sets which I have in my Abaqus input file from the user material code (UMAT) and check to which elset the current element, which is characterized by "NOEL" in the UMAT, belongs.



Abaqus UEL for von Mises Plasiticity needed

Dear all,

I need an Abaqus UEL for von Mises plasticity as sample to learn how to write a UEL for plasticity. Does any body have any similar UEL code?



Reading Abaqus input file at each increment

Dear friends,


combining UMAT and UEL

I am trying to combine UMAT and UEL in my Abaqus calculation to simulate crack propagation by using a damage criterion. My UMAT calculates the damage variable in each time increment and whenever the damage variable violates the damage criterion in one or more elements, I should seperate the damaged element(s) via XFEM theory which can be implemented into a UEL code; therefore, I should use both UMAT and UEL in my calculation. Is there any way to combine these two codes together?

Reading Abaqus .fil file

Dear all,

in order to access the last value of my state variable SDV at specific integration points and specific elements, I need to write the SDVs into .fil file in order to be able to read them inside my UMAT at each time increment.

I use the subroutine DBFILE to read the .fil file; the keyword to access the state variables is "5", but I don't know how I can go to the value which has been already written to the current integration point.

Could anyboby help?

Thanking in anticipation,


Abaqus CAE

I intend to create a
composite model, containing a cylindrical fiber surrounded by a cube,
by Abaqus CAE v 6.7-1. I create
two separet parts, one for the cube and the other one for the cylinder. Then, I
cut the cube by the fiber; the third part (lets say the cut part) is created
automatically. Now, I need to mesh the parts and merge them. 

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