Parts goes through one another during simulation

[astenath29]

Hi,

I am conducting a satic FEA on a trolley/carrier like structure. The result shows that there is high deformation of the model. Two of the parts of the model fails to recognised adjecent boundary of another part as shown in image 2.  Image 1 shows the mesh of the part before the analysis. I have used bounded contact but some reason the two L-shape pipe doesnt seem to see the axle pipe. 

Please feel free to suggest any possible solution. Thanks

Regards

Asif

Image 1 

Image 2

[AstroJohnPE]

Hi Asif,

Do the pipes have a flat spot on them where they come into contact, or are they perfectly round? Two round bars at 90 degrees to each other contact at a single point (theoretically). I'm not sure if the contact detection algorithm can handle this or if it needs an extended surface to detect the nodes in contact.

I also noticed that the pipes in the X direction are not connected to the vertical pins. If the pipe and pins are set to bonded contact, my guess is the CAD model includes a space between the pipe and pin, and the mesh matching tolerance is too small to stretch the surfaces and bring them into contact.

[astenath29]

John,

Thank you for replying. The pipe is fully round. Do you think I should create a flat spot on the pipes and than carry out analysis. I believe the pin and the pipe does have small gap or contact at single point. Thanks. 

[zhuangs]

Surface contact should be defined between the L-shape pipes and the straight pipes.  "Bonded" contact can only work for the surfaces without gap or the gap is very very small.

-Shoubing

[arizawilmer]

Hello

A first solution will be to create a small flat surface in the connection planes of the pins, then suppress the pins and use the bolt connection of Autodesk simulation to create new pin connections.

Your model is going run fast. After this you can analyze the stress over the pins. If you have welding between the tubes try to draw the elements between then.

Cheers

[astenath29]

Hello,

I have solved the problem, firstly I created the flat surface on the pipe and secondly I joined the pipe to the rivet/pin rather than mating the pipes and than attaching the pin. 

Thanks everyone for suggestions.