Element Deletion using UMAT

[@Love_roundabouts]

Very helpful indeed!! Thanks you Kian!!

[@refquesog8104]

The option deepVar is grey in my Abaqus Learning Edition 2023. Is this a limitation?

[@kianaghani]

It seems so.

[@mahdivafaei4394]

please help me what is this error

[@mahmoodmoosavizadeh9087]

If possible Please make a tutorial for concrete under cyclic loading by using UMAT subroutine.

[@kianaghani]

Hi. I believe the CDP model is quite capable of modeling these type of loading.

[@Alexinter95]

Hi Kian, thank you for your video, it was really helpful! I'm trying to model elem deletion using VUSDFLD sub, I define the parameter and the depvar for it. I've also selected "Yes" on the "Ele Deletion" option in the Element Control panel. However, the visualization do not show the deleted elements. The value of the depvar is correctly updated btw. Have you ever encountered a similar issue?

[@kianaghani]

Hi, have you tried to toggle the status option on?

[@Alexinter95]

@@kianaghani which is the status option you talking about?

[@kianaghani]

@@Alexinter95 status in the field variables

[@dongyangyi8401]

Thank you very much for posting the video! this is very helpful! I want to ask if the deleted element still have influence on the overall simulation

[@dongyangyi8401]

also would you let me know if I can run a heat transfer analysis only with this method? I want to deactivate the element above certain temperature

[@kianaghani]

First, ABAQUS passes zero strain and strain for the deleted elements. For your next Q, use GETVRM in conjunction with USDFLD to save the temp. Then, pass it into UMAT and do whatever you want with it.

[@dongyangyi8401]

@@kianaghani Thank you. I know this sounds like a very straightforward step but would it be possible for you to show a series step of passing VUSFLD to UMAT? Also in this case would you use the Coupled thermo-mechanical element type?

[@kianaghani]

@@dongyangyi8401 You can save a PARAMETER to STATEV and pass it to UMAT. The most common element is the coupled thermo-displacement element.

[@dongyangyi8401]

@@kianaghani Thank you so much Mr. Agahani!

[@mmm_2391]

Hi, thank you for the video. I am having a strange response after deleting elements where stress is still in model after element deletion. Do you have an idea of what causes this?

[@kianaghani]

hello. It is probably due to bad stress definition in the UMAT.

[@mahdivafaei4394]

i get error found invalid intiger 0

[@kianaghani]

Take a look at the log or msg files.

[@rishiraj6242]

HI KIAN, I am trying to delete elements based on threshold temperature in abaqus standard using usdfld subroutine ,coupled thermal-displacement model. The elements are not deleting. What am i missing?

[@kianaghani]

Have you checked that coupled analysis has the deletion feature?

[@rishiraj6242]

@@kianaghani yes. Now I am able to delete elements based on temperature using VUSDFLD subroutine(EXPLICIT) but not with USFLD. Next I want to delete matrix and fibers and both will have different threshold temperature values. Can it be done?

[@kianaghani]

@@rishiraj6242 yes i think.

[@rishiraj6242]

@@kianaghani thank you very much for replying , I have been trying to do enforce separate element deletion temperature but it's deleting both the fibers and matrix (sequentially, first matrix then fiber and it's using the temperature for matrix deletion to do so). To do this I am assigning different variable number controlling element deletion for fiber and matrix. here's the code in VUSDFLD: ----------------------------------------------------------------------------------------------------------------------------------------------------------------------- subroutine vusdfld( c Read only - * nblock, nstatev, nfieldv, nprops, ndir, nshr, * jElem, kIntPt, kLayer, kSecPt, * stepTime, totalTime, dt, cmname, * coordMp, direct, T, charLength, props, * stateOld, c Write only - * stateNew, field ) c include 'vaba_param.inc' c dimension jElem(nblock), coordMp(nblock,*), * direct(nblock,3,3), T(nblock,3,3), * charLength(nblock), props(nprops), * stateOld(nblock,nstatev), * stateNew(nblock,nstatev), * field(nblock,nfieldv) character*80 cmname c c Local arrays from vgetvrm are dimensioned to c maximum block size (maxblk) parameter( nrData=6 ) character*3 cData(maxblk*nrData) dimension rData(maxblk*nrData), jData(maxblk*nrData) jStatus = 1 call vgetvrm('TEMP', rData, jData, cData, jStatus) c DOUBLE PRECISION MaxTemperaturematrix, MaxTemperaturefiber ! Set the maximum temperature threshold for element deletion MaxTemperaturematrix = 180 MaxTemperaturefiber = 1000 DO k = 1, nblock stateNew(k,1) = rData(k) IF (MaxTemperaturematrix MaxTemperaturefiber) THEN ! Element temperature exceeds threshold, mark for deletion stateNew(k,2) = 0 END IF END IF END DO RETURN END