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Drilling in Composite with Hashin Damage

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Peterle123

Aerospace
Oct 26, 2020
14
Hello,

Im modelling a Drilling operation in Abaqus for a composite Material. I used the following Materialparameters to define the composite:
I used Hashin Criteria for Damage modelling. But when i try to simulate it, there is no damage and an error occurs and the modell looks like this:
How can i make the Model work, so that the Elements get deleted? Do I need more parameters? I tried to use Element Deltion oin, but it doesnt work either.

Thanks for your help.
 
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You have to add the STATUS variable to field output requests and then, after the simulation, make sure that it’s selected in Result —> Field Output —> Status Variable.
 
It seems that the damage criterion wasn't fulfilled. You can plot special variables such as DAMAGEFT to see this. Check the documentation chapter "Damage evolution and element removal for fiber-reinforced composites" for more details.
 
You should check the output variables representing other criteria as well. You may have to adjust the material properties to achieve the desired goal.
 
I checked the output variable for the hashin damage and it looks like this:
The other Hashin criteria modes look the same.
It is weird because the red parts should fail and thus should be removed from the modell. Or am I wrong? I cant change the material properties because these are given.
 
Maybe I did something wrong with the units. I use mm for lenght, kg for mass and MPa. What unit do I have to use for the Fracture Energies? I used kj/m^2. Is this wrong? If yes what would be the correct unit?
 
Indeed, units in Abaqus can be quite confusing and cause some problems. With mm used for dimensions you should define mass in tonnes. Fracture energy would be in mJ/mm^2.
 
Are you sure that deletion is enabled in Element Type window ? Which type of elements do you use for the deformable part ?
 
Now I got this Error message:

"Excessive incremental rotation of the elements in element set ErrElemExcessIncrementalRotation-Step1.

There is only one element with excessive rotations"

I also get this in message files:
"The ratio of deformation speed in element CFK_45-2.1050 vs. the
wave speed of the element, 553.613E-03 exceeds 0.3.


The maximum ratio of deformation speed to wave speed is 0.55361 in element
1050 of instance CFK_45-2 at increment 757595.
"

ow can I fix this?
 
I looked at the STATUS plot and I saw that it is still 1 for every Element, even if the MAtrix Damage is 1. How can I change the STATUS of the Element to 0 so it fails?
 
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