2D crack sim - Cohesive elements have degradation 1 but still carrying Stress - they do not break

[DomL]

Hello,

did anybody face similar problem in 2D simulation? In my crack simulation with cohesive elements they start to develop, finally they reach SDEG 1 with MAXSCRT 1 CUBESCRT less then 1, but they still carry stress like they didn't break. They are not degrading at all, they are just growing in size.
I'm using traction separation law, where I tried both displacement control and energy control for DAMAGE EVOLUTION.
I confirmed with 3 elements simulation that setup of simulation is good, but when I add more complex geometry with more elements they start to behave very strange.

*COHESIVE SECTION, ELSET=COH, MATERIAL=MATCOH, RESPONSE=TRACTION SEPARATION, THICKNESS=SPECIFIED, CONTROLS=DELname
1.0, 1.0
*TRANSVERSE SHEAR STIFFNESS
6000000.0, 6000000.0, 6000000.0
*MATERIAL, NAME=MATCOH
*Elastic, type=TRACTION
** Enn, Ess, Ett
6000000.0, 6000000.0, 6000000.0
*DAMAGE INITIATION, CRITERION=MAXS
** Snn, Sss, Stt
200.0, 200.0
***DAMAGE EVOLUTION, TYPE=DISPLACEMENT, SOFTENING=LINEAR
**0.005,
*DAMAGE EVOLUTION, TYPE=ENERGY, SOFTENING=EXPONENTIAL
0.35
*SECTION CONTROLS, NAME=DELname, ELEMENT DELETION=YES

Looking forward to any help!!
Cheers!

 

[FEA way]

Make sure that the STATUS variable is requested and check its value. Try with *Section controls, max degradation set to a value a bit lower than 1. If it doesn't help, try with *Section controls, cohesive compression damage = yes.

 

[DomL]

Hi, thanks for the input, I've come across all of these ideas through out other questions around forums.
I've tried everything, STATUS is there, and it's 1
I was trying the max degradation but nothing happens. Also, as I understood if you set it on, for example on 0.9 it means that it leaves 1-0.9=0.1 "carrying" capacity of the cohesive element.
Compression damage I've tried as well, but I could find any changes in all circumstances I had it on.

Any other suggestions?