Learning Forum

[destroy]

Hello everyone,

I am doing transient structural simulation in Fluid-structure interaction framework.

I set a bonded contact between two surfaces. According to the user's guide - "If contact regions are bonded, then no sliding or separation between faces or edges is allowed. Think of the region as glued".

However, as you can see in the deformation picture (true-scale image), there is some substantial sepatation between the bodies. What setting should I change to avoid this?

I also tried to set the same thing in connections --> joints, but the effect was the same.

I applied the contact just because these two bodies has got different material properties. Maybe there is some other way to assign different material properties to two regions, beside this contact?

kind regards

destroy

[Rameez_ul_Haq]

,if you want to model the bodies as if they are glued (i.e. there is no relative translation or rotation between the faces of contact), then there is an easier way than applying a bonded contact.
Use Shared Topology option in the SpaceClaim or DesignModuler between the two bodies, which, as the name suggests, connects/shares the nodes on each face by applying a conformal mesh on these faces. This way, you don't need to apply the bonded contact or joint any more to connect these two faces.
Bonded contact can be used if you are trying to determine the force transfer between these two bodies, and stresses/pressure on the faces of the body in connection. If your target is to only transfer the force (without getting into too much detail how much force is transferred), then the prime option to opt for is Shared Topology between these faces.

[destroy]

Yeah, thank you for help. Now it works, I just created single part of these two bodies in Designmodeler, and I used shared topology.
By the way - do you have any idea why the bonded contact did not work as I expected? I always have a problem with contact, for example some time ago I was using frictionless contact between two moving bodies and I was getting an error "the solver engine was not able to converge the nonlinear (...)", and the error was present whatever I was trying to change in settings. I mean - is it a typical situation to have difficulties solving contact in Mechanical?

[Rameez_ul_Haq]

,well I don't have your model so I don't know why exactly the bonded contact did not work. Maybe you can add a Contact Tool and check if the contact is created properly or not. Sometimes, the contact is not created properly and it doesn't work during the analysis, so a trick is to actually notice that beforehand, by using the Contact Tool. This tool will tell you if the contact will be tracked during the solution or not.
As far as non-linear contacts like Frictionless, Frictional and Rough are concerned, these contacts can cause an initial Rigid Body motion if one (or both) of the bodies (which are a part of this contact) doesn't have any other ground connections. Other times, since the contact is already non-linear, it needs to find convergence in order to proceed. If the convergence is not found, then the solution does not converge and returns an unconvergence error. There are several methods to diagnose why non-linear contact is causing a problem, and plenty of ways to tackle and deal with these problems.
I would recommend watching YouTube playlists provided by ANSYS for contacts, in order to acquire a better understanding over this topic.

[destroy]

Thank you Rameez, much apprecieated, for sure I will search for information on Youtube:)