Learning Forum

[Anita Amirsardari]

Hi ANSYS community, 

I'd like to know how I can write an APDL script to conduct nonlinear static analysis where the death command for elements can be implement based on the level of stress or strain reached in the analysis. 

I have read the post "I want to SEE the failure!" from May 2018, however the links do not work. 

I would really appreciated it if someone can please provide me with some guidance!

[Erik Kostson]

Hi

Search for that and they will be some links that might help:

https://innovationspace.ansys.com/forum/forums/topic/i-want-to-see-the-failure/

https://innovationspace.ansys.com/forum/forums/topic/ekill-and-element-distortion-in-workbench/

This is the main principle and workflow:

https://simutechgroup.com/performing-ekill-element-death-in-mechanical/

If you search for "I want to SEE the failure" on an search engine, there will be more links to look at.

Hope this helps.

Erik

[Anita Amirsardari]

Hi Erik, 

Thank you very much for the references. I was able to find a link which opened up to the APDL command for ekill. However, when I am trying to follow the script, it appears that I have an issue with applying the load such that each step is solved using the loop command. 

I am essentially running an incremental static nonlinear analysis.  A displacement load of 20mm is to be applied in 100 substeps. At each substep, I'd like to check the strain or stress level and apply ekill if the threshold is exceeded. But currently, I can see that the problem in my script is that the load is not applied correctly (without even trying to execute ekill). Essentially, in the first load step the 20mm displacement is applied, rather than 20/100 = 0.2mm, thus encountering convergence issue. The relevant part of my script is below. Could you please advise what I may be doing wrong? 

------

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Apply load on selected nodes !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
NSLA, R,1
NSEL,R,LOC,X,-100, 100
NSEL,R,LOC,Y,300
NSEL,R,LOC,Z,27
CM, n0, NODES
D,n0,UY,20, , , , , , , , , 
ALLSEL,ALL
!*
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Define Solution Controls !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
/SOLU
!total number of steps for solve
    steps=100
    TIME_END=1
    timeinc=TIME_END/steps
    time,timeinc
    solve
*do,ICOUNT,1,steps-1
  /solu
  allsel,all
  time,timeinc*ICOUNT+timeinc
  solve
  finish
*enddo