Why the elements cross each other?

Hello there, I'm running an impact analysis in 2D, and the triangle will impact the rectangulaire with a certain velocity.

image.png.ee3848770254c7621197684173530755.png

The problem is that after several seconds, those elements will cross each other as it shown in the figure. I'm wondering if it's because the interface type 7 isn't a good choose in this condition?

image.png.314f7723665d9f71fc52ff86aceefe72.png image.png.80574c847125f011dda08f5a3cae0c6e.png

And in the attachment, you can find my file .hm.

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Altair Forum User

Hi,

Please try keeping the impactor slightly apart thereby creating a small gap, and provide the Gap value in the interface card and try running.

QuyNguyenDai

@Raaaad Maybe try to refine your mesh?

Altair Forum User

I've tried the Gap and now it's better but here comes another problem that after two objects have been in contact for some time there will be some elements crossing each other, I use interface type 9. And my purpose is to make the impactor deeper, and I tried to refine my mesh, although this problem can be mitigated, the depth of the impactor insertion will drop drastically, as the calculation will stop because of negative volume of certain elements.

So do you have any suggestion?

image.png.8c1c94cf363dbb1d166deb0ec3007c20.png image.png.405c5556dd4b0f79d616bd5eea68366e.png

tinh

I think you have to simulate damage phenomena, not just contact

Altair Forum User

What does that mean? Just like I should add the failure parameters to the material?

QuyNguyenDai

Try to make both meshes with similar size within contact area.

Altair Forum User

Hi,

Provide a Gap value in the interface card as suggested earlier. You can also try with similar meshes as suggested by Q.Nguyen-Dai.

Negative volume happens when the element is very deformed and their characteristic length goes to 0. You can try running with Ismstr=1. Also check the material parameters.

In the model file shared above please recheck the unit consistency followed, especially for the elastic material.