contact problem: spring elements to surface

Hi,

I have created a Type5 contact between spring elements as slave which is impacted by a component as master(shell elements). since my requirement was to make the spring elements fail, i used failure criteria for these elements. The elements failure is accomplished well as soon as the failure limit is reached, however I could see the spring elements penetrated into the surface, when the elements are impacted. I think my contact did not work well. Could anyone please suggest if the contact type is right one?

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Altair Forum User

Hi,

How did you create the spring elements, that is are they connected to free nodes?.

Can you please share the model file so that we can review.

Ushay

Hi George,

I am really sorry, i am not supposed to share the model. Instead i have attached the presentation document to the dropbox, which describes the problem.

Altair Forum User

Hi,

I recommend to try with /PROP/TYPE13 (SPR_BEAM) spring for stitch. When the failure parameters are reached the spring element will be disappeared from the model.

Please check the gif attached along which shows spring rupture upon displacement failure criteria is reached.

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

Ushay

Hi George,

thanks for the valuable suggestion. I have tried with type 13 earlier, but even for this I need to take the contact into account right? Because the surface when hits these beam elements, creates some additional forces over them. I would like to include this effect and hence trying with the contact interface for spring and surface.

Altair Forum User

Hi,

I don't think its possible to establish a connection between the spring elements and a surface. Only those nodes can be added but I don't think it will serve the purpose in this case.

Ushay

I too have the same opinion. I will let you know if I find a way. Thank you so much.

Ushay

Hi George!

I am trying to plot the force exerted by the surface over these spring elements. I have requested for the Spring forces in TH plots, however this gives the plot based on the Force-elongation curve that I defined in the failure criteria of the Spring elements. How to get the maximum / exact force the surface exerts on these spring elements?

Altair Forum User

Hi,

Since the user provided a rupture criteria the spring elements will behave accordingly and we will be only able to capture the forces based on its behavior.

Else you will have to try removing the rupture criteria so that you may get the maximum force exerted on the spring elements.

Ushay

Hi George,

thanks for that. But as per the manual, all the data for this property is mandatory, so I cannot go ahead by deleting the curve definition and failure criteria. Is there anyway to do with other type of property? I have an idea to implement prop type 13 spring_beam elements, but this also needs force vs displacement data. That would be great if you can give a tip. Thanks

Altair Forum User

Hi,

These are two different scenarios you are specifying.

If you are interested to know the maximum force exerted on the spring elements at a particular time you have to remove the failure parameters and run the analysis and has to check the maximum force.

In this case, you are specifying a failure, that is user is failing the elements at a particular criteria and so we will not be able to know the maximum force exerted on it.

Could anyone please suggest if the contact type is right one?

Regarding the contacts between the spring elements and surface, can you try with Type 11 interface, which is used to simulate impact between lines for 1D mesh, or edges in shell and solid meshes. Please go through https://www.youtube.com/watch?v=mLGwVwYSmt4&index=4&list=PLQ7KUGFuVz4u5y3SvIEIU07427-gATaG6 which shows modelling a Type 11 interface in RADIOSS.

Ushay

Thank you very much George!