Pressing - MES

[Anonymous]

Hello dear,

I'm trying make a simulation of a uniaxial powder pressing with friction on MES of Autodesk Simulation Multiphysics, but I had some problems:

1- Constitutive model Drucker-Prager of talc powder.

2- Frictional contact between the surfaces of the parts.

The model is constituted of a mold fixed, two alumina parts, a on bottom and a on top the talc powder, a talc powder part that will be pressed and compacted, and a mlc part that wiil be fixed by the talc powder pressed and deformed! A pressure of 3 bar is aplied on the top alumina part. There is friction between the talc part and the all others parts. I wanna study the stress on mlc part by the pressing of talc powder!

When I have tried to model the contact law and the powder material of the talc part by Drucker-Prager, was errors!

Please help me!

I'm sending my FEM model archive to you can see and understand better! If you want the CAD model archive I can send too!  Any doubt send me a message or e-mail, fellipezanelatto@gmail.com

Best regards,

Fellipe.

[zhuangs]

Hi Fellipe,

I did not see any contact pairs defined in your model when I opened the file pressing.zip.  And it seems that you attached a model before you checked it.  Since when I ran the simulation, the mesh module first runs.

There is an error related to the 3rd part, which uses "Isotropic" material model rather than "Drucker -Prager" in "Element Definition", and the material properties (Young's modulous, Poisson's ratio, etc.) are not defined.  If the user selects a material model in "Element Definition" and want to input a new material, the user has to input all the necessary material properties.

If you want to use  "Drucker -Prager" for the 3rd part:

(1) Double click "Element definition", select "Drucker -Prager", and then click "Ok" to close "Element defination" window.

(2) Double click "Material < default >" , then click "Edit Properties" to difine the material properties.

-Shoubing 

[Anonymous]

Hi,

I didn't understand very well, I didn't define contact properties and material properties of Drucker-Prager model because whem I tried was wrong. I tried many modes but nothing was good. Do you understand my problem? If yes try enter with the right conditions to simule my model using parameters default that I change the values here, please!

And another doubt, have I always check the model before of simule?

Thank's very much!

Fellipe.

[zhuangs]

You don't need the 'check' the model before 'run simulation', since 'run simulation' includes all the processes of 'check' at the beginning.  

 First of all, for talc powder, I am wondering what kind of material model you prefer, and whether you know any material properties.

Second, based on my investigation on the boundary load and constraint groups, it seems contact happens:

Part/Surface   with   Part/Surface

     3/6              with       4/15

     3/6              with       4/20

     3/7              with       2/15

     3/7              with       2/20

     1/3              with       2/22

     1/8              with       2/23

     1/8              with       3/5

     1/8              with       3/8

     1/8              with       4/23

     1/2              with       2/19

     1/2              with       3/5

     1/2              with       3/8

     1/2              with       4/19

But I am confused by Part 5.  There is no boundary conditions on it, and what constraints its motions? Bonded with Part 3? or contact with Part 3.

-Shoubing

[Anonymous]

Hi Shoubing,

About the constitutive material of talc powder, part 3, I studied that the better model is the Drucker-Prager but I didn't find parameters to talc powder, only to other powder types, you can use any parameters default using the Drucker-Prager model, or if you don't find any parameters, use any other model that represent a powder!

About the contact between the parts, there is friction between part 3 and part 1 on cylinder, there is friction between part 3 and part 5 on 4 faces, and all others parts in contact!

The part 5 is constrain in bottom face by a spring to limit your motion in Z axis and is locked by stress and friction from compression of part 3 that is compacted and molded by pressure on part 4 up and limited for the part 2 down. The part 1 is fixed, limit the course of part 2 and mold the part 3 with friction!

Thank you very much!

Fellipe.

[Anonymous]

Hi Shoubing,

did you see my problem? I specified the conditions in previous message, help me please!

Thank you so much,

Fellipe.

[zhuangs]

I will modify your model based on your further information and will let you know soon.

-Shoubing

[Anonymous]

Hi Shoubing,

Have you modified my model? I'm looking forward to see! Any problem contact me.

Fellipe.

[Anonymous]

Hey Shoubing,

pleaseee! did you see my problem?

Thanks,

Fellipe.

[zhuangs]

Hi Fellipe,

I will help modify your model and do some further testing and investigation, probably today, since I am quite busy recently.  I will let you know more information if needed this afternoon or tomorrow morning.

Shoubing

[zhuangs]

Hi Fellipe,

I just sent email to our technical support team for help to set up your model.  Later I can help them make your model run.

Shoubing

[zhuangs]

Hi Fellipe,

I added some contact pairs on your model (with static friction coeff. 0.3, dynamic friction coeff. 0.2, since you did not provide these data), with some setting changes as well, but no good running is obtained.  Further investigation found that your model has some unnecessary bonded nodes in your mesh, for example, between part 1 and part 4, as shown in the attached figure.  In this case, MES contact cannot work well.

Shoubing

[Anonymous]

Hi Shoubing,

thank you very much by attention, could you send me the model to see? How can I eliminate this nodes in contact? But whem the model run, what results? errors or warnings? or nothing? and what the most available mode of simulation to this problem if not MES?

Fellipe.

[zhuangs]

In this case, the model cannot converge well or at all.

In the modified model ( the model is sent to you), I disable part 5 since at first I didn't know its feature.  If we can well set up the model: mesh, contact pairs, etc., the model should work well.  After all, it is not too complicated.

However, I cannot dedicate too much in your model.  Two options:

1. Please well mesh your model, and the define all necessary contact pairs, like those I added.

2. Call 1-866-487-8680, then choose option "6", then option "4", to contact our technical support team for hep and support.

For either of the two options, once the model is well set up, I can help, if needed, to set contact setting to make the model run.

Shoubing

[Anonymous]

Hi,

I changed the model but the frictional contact keep with problems, the simulation gives errors and warnings when I don't use default contact bonded, why?

Thanks!

Fellipe.

[zhuangs]

Hi Fellipe,

I am wondering whether you fixed the matched node issue and whether you well set up all the necessary contact pairs.  Why no post or upload your log file and let's see what are those errors and warnings.

Shoubing

---

fellipezanelatto wrote:

Hi,

I changed the model but the frictional contact keep with problems, the simulation gives errors and warnings when I don't use default contact bonded, why?

Thanks!

Fellipe.

---

[Anonymous]

Hi Shoubing,

I'm trying send you my model to see but the file size is too large, can you pass me your e-mail to send? Take a look at frictional contact surfaces that I disabled to run but active please! And, if possible, change the material properties of  talco_compacted part to a any kind of Drucker-Prager constitutive material because I didn't get it!

Thanks!

Fellipe.

[zhuangs]

Please use “Archieve->Create->Save (model only)” to create .ach file and then send to me.  Only the .FEM file is not enougH.  Moreover, send me your log files with the errors or warnings which you mentioned.

Shoubing

[zhuangs]

Hi Fellipe,

Your updated model has been modified to run smoothly with frictional contact.  The modified has been sent.

Shoubing