Contact between parts with 0.1 mm clearance

gopal_rathore

Hi @George P Johnson

I am working on a contact between two surfaces (Both of steel materials having hollow circular section)having clearance of 0.1 mm . I was using TYPE 19 contact but facing issues in the same and one of the node in the interface reduces time step.

Parameter sued with TYPE 19: Istf :4, Fric: 0.1, Gap min: 0.1, Inacti6, Iform2 .

 

Any other parameters recommended for solving type 19 ?

 

Thank you

 

 

Altair Forum User

Hi,

Can you try with a minimum stiffness (Stmin=1000N/mm)?.

If you still have issues use /DT/INTER/DEL option in engine file so that those slave nodes below the Tmin specified will be suppressed from the interface. This node will no longer impact any master segment for this interface.

Normally for zero gap contacts we model with Type 24 interface. This option also you can try.

gopal_rathore

Hi,

Time step is coming on a node which is in the interface and it keeps on reducing.. Are your referring time step for interface?

Altair Forum User

Hi,

If for some reason a node is highly penetrated, either the nodal time step or the kinematic time step may be very low. Then, it is possible to release this node from the interface using the option /DT/INTER/DEL in the engine file. All nodes reaching dtmin will be removed from the interface.

But please note that this option may be useful in order to keep a decent time step during contact, but if the number of released nodes is too large, poor results can be expected. 

gopal_rathore

Yes,

If no. of nodes is high, the results would be affected.

Earlier the interface was type 19 and now I am currently making it as TYPE 7 to see the effect. as even help also says that the Will update.

gopal_rathore

Hi @George P Johnson

Type 7 is also creating nodal time step issues.

 

For Type 24, can we have contact surface to contact surface contact? 

Any other parameters to be taken care of?

Altair Forum User

Hi,

Yes, you can model Type 24 interface with contact surface to contact surface.

No other specific parameters to be taken care.

gopal_rathore

Hi @George P Johnson

is it recommended to make type 24 between solid elements ?

I have solid components and have shell element layer of 0.01 mm thickness for making the type 24 contact. 

 

Also is there any difference if I sue type 19 in one go and type7 and type 11 at same location differently

 

I am facing issues in contacts in a simulation of high speed impact

 

I am sharing .gif through the secure link for overall problem overview

Altair Forum User

Hi,

Type 24 is recommended for all models where there is no physical gap (solids to solids) and also with negligible gap.

 

Altair Forum User said:

Also is there any difference if I sue type 19 in one go and type7 and type 11 at same location differently

I don't think this approach is required. Try with any one of this approach (directly Type 19 or Type 7 and 11).

 

Altair Forum User said:

I am facing issues in contacts in a simulation of high speed impact

Which type of contact is used for this model?. You can try introducing a Stmin value and also introducing a symmetric contact.

gopal_rathore

Hi @George P Johnson

I am using a combination of Type 7 and type 11 in one location and type 19 in another location. I have used type 24 but as this does not take care of edge to edge to edge contact, I am facing issues in intersection and thus Type 7 and type 11 needs to be used

The model was ran with DT/NODA/CST and at one point one of the noes in the type7, type11 combined interface became vulnerable and every other component in connection starting converging to it and ultimat ely leading to mass error (Image attached)

I am sharing one more gif. through secure link along with .out files

 

I am iterating with type 11 contact parameters, yes I have used Stmin: 1000

<?xml version="1.0" encoding="UTF-8"?>

jsk459

Hi All,

 

Could you please tell me which contact (type 7 or type 24) is better for very small and closely components with fine mesh(High impact quasi static analysis) without using GapMin, since if i use Gapmin again i need to de-penetrate due to this the original geometry will also change.  

 

Thanks,

Senthilkumar

Altair Forum User

Hi @jsk459

 

With type 7 there is a limitation that with a small gap time step is affected.

 

Use type 24 and it serves the same purpose. 

jsk459

Hi ,

 

Thanks for your suggestion. I think Type 24 is the surface to surface contact(As Ls dyna). How to use it as single surface contact in RADIOSS? 

 

Altair Forum User

Hi,

 

TYPE24 is a general node to surface contact interface using the penalty method. Three types of inputs contacts can be defined: single surface, surface to surface, or nodes to surface.

jsk459

Hi,

 

In general for single surface while selecting components it will show only the slave components selection option. but in type 24 both master and slave selection are present. Please let me know how to choose components for single surface ?

Altair Forum User

@jsk459

 

Single self-impacting surface only: surf_ID₁ > 0, and surf_ID₂ = 0

 

Select only one surface and second surface should be zero. 

jsk459

Hello All.

 

I hope that for No gap components it is better to use the Type 24. So is there any recommended properties for type 24 other than the friction value ?

Altair Forum User

@jsk459

 

Ipene set to 1 which includes self impact.

jsk459

Hi ,

 

In type 24 contact i can select all the components directly instead of creating & selecting the contact surfaces ?

gopal_rathore

Hi,

Yes you can do this, I prefer Hypercrash for making contacts . You can select components as slave and master and make contact between them.