Jump to content
gslee

Question about Variable Gap and Gapmin of type 7

Recommended Posts

Hi,

 

I want to know if what I thought is correct.
 

The interface setting of two shells is as follows.

 

image.thumb.png.31b416bca7b47339344ab36941349e89.png

 

Top shell is 1T and bottom shell is 3T.

 

Distance between two shells is 2mm. -> No initial penetration

 

image.png.998a1f031e17280557cc1ef4ae3995b6.png

 

 

Igap determines how the size of the gap is calculated.

Igap = 1 

 

 

image.thumb.png.f76d09d1fcdc29aeb881c457b9cfb3a8.png

Then, in my model,  Variable Gap = 2

 

And then my question is as follows.

 

In this model, if Gapmin is 1.5 , contact force is applied when distance between two shells is 1.5 below figure??

(when  1.5 < distance between two shells, contact force is not applied???  )

 

image.png.3b471515c5806a851dbe6b3143986a06.png

 

Thanks

 

Share this post


Link to post
Share on other sites
3 hours ago, gslee said:

 

In this model, if Gapmin is 1.5 , contact force is applied when distance between two shells is 1.5 below figure??

(when  1.5 < distance between two shells, contact force is not applied???  )

 

Due to Igap = 1 the variable gap will take highest value; in this case Variable Gap = max [Gapmin=1.5,(gs+gm)=2= 2 

 

In case the initial distance between shells is 1.5 there will be initial contact penetrations, which can be handled by Inacti=5 or 6 or Fpenmax.

 

 

Share this post


Link to post
Share on other sites

Hi,

 

in my model, initial distance is 2.

 

If External force is applied on model and gap distance is small.

 

And then if gap distance ≤ 1.5, contact force is applied??

 

Thanks

Share this post


Link to post
Share on other sites

The contact force is applied when the distance between the shells is less than the Variable gap calculated as follows for your model,

thickness slave shell = ts=1

thickness master shell = tm=3

gs=ts/2 = 0.5 mm

gm=tm/2 = 1.5 mm

Gapmin= 1.5 mm

Variable Gap = max [Gapmin,(gs+gm)] 

Variable Gap = max [1.5,(0.5+1.5)] =2 mm

 

So the contact force will be applied when the shells are 2 mm apart.

 

If using variable gap then Gapmin can usually be left blank and a default value is calculated by Radioss which is typically smaller than the variable gap.  However, since there are few situations where the calculated default Gapmin can be larger then the variable gap, we typically recommend setting Gapmin to a value which is 1/2 the thickness of the thinnest part.

 

Thanks,

Andy

 

 

Share this post


Link to post
Share on other sites

Thank you so much.

 

If I use variable gap, gapmin must be smaller than variable gap.

 

And in that case contact force is independent of gapmin value.

 

Is it right?

 

Thanks

 

 

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
You are posting as a guest. If you have an account, please sign in.
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...