Problem of interaction between two parts

[Loic42]

Hi everybody,

I'm in my first year of master's degree in mechanics and materials, and currently doing an internship for which I need to perform some simulations on Abaqus.

I work on a drilling process: carbide is used for the drill bit, and titanium for the workpiece.

I created the model on Abaqus (3D, dynamic, explicit), but after running it I don't get any results: anything is calculated even if the simulation is working (I mean the drill bit is rotating and translating, but pass through the workpiece without any interaction).

I made the hypothesis that the body is rigid and the workpiece is deformable. I created a tie constraint between the two parts, and define a friction coefficient.

For the titanium I used a Johnson Cook model, I filled the damage evolution and the plastic behaviour. Same for Carbide.

I ticked STATUS in my output fields.

But still nothing. Someone got an idea please ?

Have a good day,and thanks for your help

Loic




Ps: In the Warnings in get some comments of which:

"Some nodes involved in general contact have penetrated their tracked faces by more than 50.000 percent of the typical element dimension in the general contact domain, 3.1049. Please check the node set "InfoNodeDeepPenetFirst". Please make sure that these nodes and their contacting faces have sufficient mass to allow the code to calculate realistic contact penalties for enforcing the contact constraint.

All nodes involved in general contact that have undergone deep penetration of their tracked faces during this step have been listed in node set "InfoNodeDeepPenetAll". Please make sure that these nodes and their contacting faces have sufficient mass to allow the code to calculate realistic contact penalties for enforcing the contact constraint."

 

[Mustaine3]

Tie with friction and then messages regarding general contact? Maybe you start with easier models and become familiar with these options first.

 

[Loic42]

Thank you.

OKay, but the two things are different.. Let me know if I'm wrong, but the Tie constraint I used is to constrain the cutting edges, while the friction coefficient is to manage the contact between the tool and the workpiece... One doesn't rule out the other, isn't it ?

Thks

 

[Mustaine3]

With the tie you glue one region on another to prevent relative movement. Then a regular contact is usually unnecessary, because without any relative movement you need no contact.

 

[Loic42]

Yeah I agree for the tie. However I don't understand for the regular contact sorry.

By the way I search on the internet for my problem and find something which explains that it was due to the necessary to give a mass and an inerty moment..

But still not work. If someone has an idea, I'm still working on it,

Thanks

 

[IceBreakerSours]

You do not know what you are doing. Take a week (or more!) to start from the basics. Open the Getting Started guides in the documentation and go through them diligently.

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[Loic42]

Hi,

As you told me, I took the time to investigate the documentation of Abaqus, and even if at the beginning I thought it was not helpful, it finally was!!
I finally started again the design of my simulation on my own on Abaqus, and I think I understand everything more deeply.

The thing is, now I face a problem that I'm not able to solve even with my research in the doc, on the Internet, on forums...

During my simulations, the drill bit cuts the work piece, it deletes some elements but there is still a part which stays in position (refer to the attachement please) and the drill bit finishes by passing through the rest of the part.

It seems to cut only the first layer of elements and the last one (the ones of each surface)...
Does someone have an idea to solve this problem please ?

Thanks for your help, and hope this time someone will be more specific as well as I've made a lot of efforts to get my current result, and think I'm able to understand more about explicit method on Abaqus and this kind of work.

Sincerely.

 

[StefCon]

Hi,
Check out the picture im attaching. Maybe it helps with the contact definition (General contact).

 

[Loic42]

Hi,
Thanks very much, I try to figure it out with your picture and get in touch with you,

 

[Loic42]

Thanks so so much ofr your detailed explanations. You gave me the way to succeed.

Thanks so much, no let's optimize the mesh and simulate chips...

By the way, do you have an idea regarding the chip formation? I still have to investigate that, but for now I've not found a proper way to do that.

Thanks again, have a good day.

 

[StefCon]

Chip formation? I think that will happen automatically when the material data is correct and the model/mesh is good enough. How "good" is your current material data? Refining mesh can sometimes allow for chips to form.

The material data is hard to obtain. I can imagine that it will have both strain rate dependence and thermal dependence (inelastic heat generation and friction).

Take care when picking element type.

This is not an analysis that you do in your back yard. Some people do their phd in these things.

Cheers!

 

[Loic42]

Yeah I think so. Actually some chips are created during the simulation, but they don't look real, and for example they don't exit all along the flutes but by the other side of the hole.

The workpiece is made of titanium, and the material data I chose are quite good I think. Later I will add a carbon fiber composite so the problem will be more difficult considering the data will be less reliable.

I think I will work harder on the mesh first.

Yeah I guess. You mean thesis on material data or drilling simulations ? Indeed I did a review and found some interesting papers on both.

Thanks very much for your help.

 

[daBroo]

Hi,
I'm also making a drilling simulation in Abaqus for my masters degree and it would be very helpful if you send me your .cae or input file, I have minor problems in my simulation. My mail is antedabro_1@hotmail.com. Thanks in advance!