Panos Efthymiadis's blog

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.

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

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..

Dear all,

      I want to model crack initiation and propagation for a user defined material, using Abaqus. When I try to model , I get the following error:

A MATERIAL PROPERTY THAT IS NOT ALLOWED WITH A USER MATERIAL HAS BEEN SPECIFIED

when I take out critical damage initiation, the model works fine; which means that it doesnt allow me to couple UMAT with crack initiation. Does anyone know how to handle this problem?

All the best,

         Panos

Dear all,

      I would like to ask you how is it possible to import into abaqus a 2-D or a 3-D Voronoi structure. so far I ve been able to create my grains into Matlab or fortran but I dont know how to import them into abaqus.

All the best,

    Panos

Dear all,

       I would like to ask you, how is it possible to simulate fatigue in Abaqus. I have created my loading. But if I run it as it is it will never reach a critical value, so you could say there is no damage evolution. Is it the only way is to apply some type of hysteresis loop evolution and say that after some cycles the hysteresis loop changes?

Any advice is more than welcome!

Regards,

            Panos

Hi,

 I d like to ask you how could fatigue loading be modelled in cae. I know that you can set up the load as a sin function with min and max values. But where do you set-up the total nr of cycles? Is at the step part and where exactly?

And another question could anyone provide me with details of the input file for the hysteresis loop, where the stess nd strain resistance of the material drops after certain cycles..

Regards,

   Panos

Hi all,

       I am having some troubles with the extrude command in Abaqus cae. I have modeled my sample as a 2-D geometry and now I want to move to 3-D for the same section. But I am having trouble extruding my 2-D section. It seems to me very weird and far to complicated the extrusion process in abaqus for such a simple task...

Thank you,

          Panos

Hi all,

             I would like to ask how is it possible to import  a sketch or a part into Abaqus without using any other software needed, like CATIA, PARASOLID etc... Currently I am using Matlab to create my geometry. What I obtain is my exact geometry in terms of points given by x,y and z coordinates in txt format or inp format. But still struggle to import my geometry into Abaqus. Any help, more than welcome...

Best regards,

              Panos