Jump to content
Farzin

Contact Penetration

Recommended Posts

@Prakash Pagadala

Hello Prakash,

I am trying to simulate a model with several contacts in Optistruct (Non linear quasi static). The Materials are all linear but with very Little Young Module (40-300Mpa). But there are big Penetrations between sliding parts and the results are not correct.

Contacts with Problem:

 ID 16

 ID 17

 ID 26

 ID 27

 ID 28

Penetration.thumb.jpg.7fdc3164d36142f59c6212ecb04f2194.jpg

 

I have followed all Solutions in this Forum but it did not work out. I have tried following Solutions:

-Contact type: SLIDE

-Nlparam NINC increase to 200

-CNTSTB load collector  and CNSTB Card in Param (EXPERTNL)

- MORIENT= Opengap

-Additional Clearance: 0.1

-String Value>>Adjust>> Auto

-S2S and N2S (Both tried)

-Track INFINIT and Consli (Both tried)

- Symmetric Contact for IP 16  (2 identical contacts with reverse Slave/Master Component)

- PCONT>>STIFF>>HARD

Because the Simulation takes so much time i share the H3D results too.

 

Thank you so much for your help

 

P.s: I should mention that this Model with this Material Parameter has been simulated successfully in Abaqus.

 

Share this post


Link to post
Share on other sites
Guest

OK, 

I have modified the model a little and waiting for the analysis to come out. I will update you soon,

Share this post


Link to post
Share on other sites
Guest

Hi @Farzin

 

LGDISP is not working. I tried the same. I tried after few modifications and I see no penetration but the model doesn't converge for 1st subcase.

 

I am trying to fix the same and I will share the updated model soon,

Share this post


Link to post
Share on other sites
Guest
23 hours ago, Farzin said:

Currently i am trying a high value of NINC 1000. It takes a week to have the results.

I think NINC has nothing to do with that. 

Share this post


Link to post
Share on other sites
Guest

Hi @Farzin

 

Can you try with N2S and provide a stiffness of say 1e5?

 

You can try with increasing the stiffness, but that may not give reasonable results.

 

I will update my finding soon with another modeling change...

contacts.png

Share this post


Link to post
Share on other sites

Hi @Prakash Pagadala

I am very thankful for your help.

I will try your idea and update you the results.

Also the results from NINC 500 are out. (The loads are a Little different, but the principals are the same)

There is 2 issues that i found:

First. there is a jump in the Situation of the Geometry between load step 1 and load step 2. (With CNTNLSUB in Load step 2)

it resets some parts of the geometry. I dont know if it causes the contact Problem, in first load step the contacts are functional a Little but it gets worse in load step 2.

 End of load step 1

1.thumb.JPG.a2e14c0a136154c5360d97a43df1ab15.JPG

Start of load step 2

2.thumb.JPG.de8cf5979109f4b93a796b8a5f85f3ac.JPG

 

Second. As you can see in the first Picture, the pink part follows the blue part and goes upside ( Just like that it is Stick contact but it is actually slide) and i expected that it stays down.

Here is the Result file (Please ignore the movement of parts at the front, because the pressure was defined in incorrect direction)

 

https://www.dropbox.com/s/kmekskydyey7eie/R464.h3d?dl=0

 

Share this post


Link to post
Share on other sites

Hi @Prakash Pagadala

New Update: i tried your idea with stiffnes 1e5 (NINC 100) and the results are so similar to NINC 500 (1 week calculation) but in a very shorter time (10 Hours), which it makes your solution more helpful. The Level of penetration is the same. Not ideal but much better than the initial Situation.

 

Share this post


Link to post
Share on other sites
Guest

Hi Farzin,

 

It took 2 hrs on my machine with 1E5 stiffness. But my NINC is 10. 

 

Increase stiffness may give good results. 

Share this post


Link to post
Share on other sites

Hello @Prakash Pagadala,

New Updates: I have tried a new Setting with LGDISP and the contacts work very good without any Penetration but the Problem is that in Loadcase 2 it does not converge after 60% and the elements beginn to deform incorrectly, i have tried NINC 100 for loadstep 2 and it didn't help. Do you have maybe any Idea about this Problem?

I appreciate your help

FEM:

 

H3D:

https://www.dropbox.com/s/9e5cllc9r4s1m7p/T54.h3d?dl=0

Share this post


Link to post
Share on other sites

@Prakash Pagadala

Hi Prakash,

i found 2 wrong values in the model that i sent you. Could please correct them:

1- Node Set (ID= 2) ist redundant, you can delete it

2- The material Parameter for Material Meniscus (ID=3) ist E=59 and Nu=0.49

I am so sorry for the this wrong Settings

With Best Regards

Farzin

T544.fem

Share this post


Link to post
Share on other sites
Guest

HI @Farzin

On 9/21/2018 at 10:24 PM, Farzin said:

1- Node Set (ID= 2) ist redundant, you can delete it

 

I have deleted this already and ran the model and it converges to 70% 

 

Let me try with new material values and i will share my feedback soon,

Share this post


Link to post
Share on other sites
Guest

Hi @Farzin

 

The simulation is stuck at 70% convergence since the last couple of days and I have a .nl h3d which is around 4gb which I can't share right now.

 

I will check with experts on this and update you soon,

 

 

Share this post


Link to post
Share on other sites
Guest

Hi @Farzin

 

Any update?

 

If not, try with these settings, 

Use S2S instead of N2S

Use CONSLI instead of FINIT

Set S1=1.0e-4 in CNTSTB

Add NLADAPT, NOPCL,0 and run in 2018

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...