Friction supports

[kiran.narsey]

Hi,

I am trying to generate a model with a friction support in 2 directions for a 3D model. Ive had a couple of queries come up with this:

1. I cannot add the friction support if both the X and Y direction are released?
2. When fixing a direction in the friction dialogue box in regards to the above, it appears to default back to a rigid support when inspecting the support after

Any clarification would be appreciated

[rsousa_]

In 3D model you can have friction supports in X and Y direction if direction in bearing pressure is defined in Z direction.If you don't check those direction in friction support menu, they will behave like friction supports in that directions.

If you check one direction it will become rigid in that direction.

It is not very intuitive and i think help file has an error when it  says:

"Support - Friction

During structure calculations the following conditions (for each case) are checked at each support with defined friction:

- for 3D structures (if two directions are released):

Ffrict (dir 1) < mi * Fn / gM + To

Ffrict (dir 2) < mi * Fn / gM + To"

In my opinion, the RSA will converge (as it should...) if the the total force is lower than mi * Fn / gM + To and not in each direction, as stated.

Regards

[kiran.narsey]

Thanks for your response. I understand the logic behind the friction support, however still have the original queries. I have included a few screen shots below to try explain. The first screenshot shows what I get when trying to add the friction in a 2D sense. The last screenshot is a result of trying to update the support after having fixed the UY direction to allow me to add the support.

 Without either UX or UY selected, I am unable to add the supportSupport listdouble clicking on the "friction" support takes me to the rigid support dialogue box

[rsousa_]

Have you tried fixing UZ direction before going to friction menu and checking friction option?

That will enable add button and maybe solve your problem.

[Artur.Kosakowski]

Hi @kiran.narsey

Try to define a new e.g. pinned support label first  first and then create a new friction with two horizontal directions being 'released'.

If I managed to answer your question(s) press the Accept as Solution button please. This will help other users to find solution(s) much faster. Thank you.

[kiran.narsey]

Thanks for the suggestions - was able to add the support based on each, however it still posses the issue that when I go to update, it takes me back to the "rigid" support inputs.

Additionally, when I run the model, it was providing an instability (even though hand checks show there should be sufficient capacity in friction alone). I feel this highlights that the support is not being considered correctly (roller as oppose to friction)

[Artur.Kosakowski]

Hi @kiran.narsey

I'm not sure how to understand the update part. What exactly did you want to change? Could you attach the current version of the model?

[kiran.narsey]

Hi Artur,

I have tried numerous times to attach the model, however it is not working. I have also tried on another post I submitted to no success. Is there an email address I can send the model to?

In this instance, the original model is the same.