Separation contact not working

[e.hopDXAM3]

For a FEM analysis I'm using the stress analysis plugin of autodesk inventor 2017. Here I'm analysing a cover with a snap fit hooks that clicks onto a product. The product slides over the snap fit hook and pushes it away untill the snap fit hook engages. I tried to simulate this by applying seperation contacts between the relevant surfaces on the product and the cover. This works well, but the seperation contact also seems to continue outside of the product which is causing the snap hook to bend further without engaging (see attached picture).

I don't understand why this manual contact seems to continue outside of the product itself. Maybe somebody has encountered a similar situation before and knows how to let the contacts work as planned?

[g.ceruti]

have you checked the deformed amplitude factor in the deform options tab?

try to set to "Actual" and set the factor to 1

[e.hopDXAM3]

Thanks for your reply, but the picture I posted previously already has the deformation setting on actual, so its not the case that the deformation is shown exagerated.

[shigeaki.k]

Hello @e.hopDXAM3,

it may have something to do with your contact setup.  Can you paste the screenshots of the contact settings or attach the actual model? Could you also check that you have not selected additional surfaces for contact definition by mistake? 

Regards,

Shigeaki K.

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[e.hopDXAM3]

Beside the automatic contacts I created manual separation contact between the radius of the snap hook and the chamfer on the products which it interfaces with (see attached picture). This is what I did for 6 edges and created another seperation contact on the bottom of the product to serve as a stopper.

I also tried other manual contact configuration where I also created seperation contacts between the radius on the snap hook and sufaces on the product above the chamfer, but this made no difference to the result.

[swalton]

Quick Question:

Are you using Nastran In-CAD or Inventor Professional's native FEA tool?   

[e.hopDXAM3]

I'm using the Inventor Professional's native FEA tool

[Roelof.Feijen]

Hi @e.hopDXAM3,

If you look at the deformation results, do you look at the actual deformation or the exaggerated deformation?

Would it be possible to attach your model?

If you do not want to share it in public, maybe you could send me a PM with a download link?

[e.hopDXAM3]

Hi Roelof,

The deformation was set on actual as you can see in the picture I attached to the post (btw I'm using the Inventor inCAD stress analysis tool). It seems like the manual contact is extrapolated outside of the actual model.

I'm new to this forum, what is a PM with a download link?

[Roelof.Feijen · Accepted solution]

Hi @e.hopDXAM3,

PM stand for Private Message.

Download link. I use WeTransfer to create a download link and send the link to someone else.

BTW. This post should be in the Inventor forum, not in the Nastran In-CAD forum. Maybe a moderator can move this pots?