Ansys contact problem!!

[lgianluca]

Dear friends,
I'm dealing with a spring sheet inserction on a tube.
I'm conducting a static structral analysis because i would understand the max stress on the spring element.
The simulation is a 2D sim. to let reduce the computing time.
The friction contact was regularly detected (see image attached).
My problem is that applimg a displacement on the spring i'm not able to see the spring deformation (see results images).
Please help me because i'm loosing mi life!!!!!
Thanks friends!!

 

[Erik Panos Kostson]

Not sure what you need help with.

The spring is being pushed down, and it slides perhaps along the semi sphere (not sure if contact is working). Basically a rigid body movement (visible on the images).
It will slide of course if there is not enough friction force to prevent it.

Also the part seems to be 3D?

If someone is to help more information and clarification is needed.

 

[lgianluca]

Dear Erik,
thanks for the reply.
The model is 2d (you see 3d because i active 3d ansys representation).
yes basically it's a rigid body movent. I set a friction coefficient of 0,1. Anyway geometrically it should there be a spring deformation but it doesn't happen.
Why?

 

[lgianluca]

if you see the second image there's a penetration of the spring inside the sphere, why?

 

[L_K]

One load step is sufficient for the analysis. Initial contact (8 elements) is detected which is good.
You could try setting number of substeps to 100. Also check the mesh size in the contact area,
too coarse mesh can cause trouble.

 

[lgianluca]

Dear L_k I decreased the load step (the displacement of 5 mm was decreased in 2 load step). I increased the substep to 500 but there's again penetration of spring and so any deformation. The mesh also was increased but i can't understand what is wrong!!

 

[Erik Panos Kostson]

If it is not confidential post you files and perhaps someone can have a look.

 

[lgianluca]

Dear Erik,
it's possible post the files? if yes, in which way?
Thanks!!!

 

[karachun]

Use any of file exchangers, Google Drive, Dropbox etc.

 

[Erik Panos Kostson]

You can also do it here see image below:

 

[Erik Panos Kostson]

Test for upload


Seems to work

 

[karachun]

Also it is good form to tell version of Ansys and clear mesh and calculated data before creation of archive.

 

[lgianluca]

Dear friends,
attached the link of simulation

https://we.tl/t-qfPNxpmk4o

The simulation was not runned for space issue.
Thanks!!

 

[lgianluca]

version of Ansys is 17.0

 

[Erik Panos Kostson]

A 3D shell (say that is used for a 3D slab). The geometry should be set to 2D for plane stress and strain analysis (go to the geometry, right click and select properties in the in the properties of schematic geometry, set the drop list set to 2D instead of 3D). So if you convert the geom. to 2D (also project to the XY-plane), and use a lower initial contact stiffness with an aggressive stiffness update, it works fine. See image below for this contact setting. Attached also the 2D projected geometry I used (imported to Strand7/Straus7 in Italy, projected there and exported back out).

Link

 

[lgianluca]

Dear Erik you have right!!
The problem is that i was seeing 2d surfaces without setting it right.
Now i designed the 2d skecth directly on design model without importing it from a cad software (conversion errors!!)
Below i report you my updated simulation but it's not working for convergence problems.
i have a good mesh a high substeps and loadsteps. Could you check it? thanks a lot!!!!

https://we.tl/t-EYPzdRESfe

 

[Erik Panos Kostson]

See the attached instructions. Follow them in detail and it will work. That is it for me now, I will be quite busy today so I will not have anymore time to look at it.

 

[lgianluca]

Dear Erik thanks a lot for your availability.
I will try and let you know.
thanks agsain friend and if you will come to Italy let me know!!!

 

[Erik Panos Kostson]

Prego. have a good weekend and let me know how it goes.

 

[lgianluca]

Dear Erik your suggestions are working well!!, thanks again