Static Pinned simulation

[scastrophotography]

Hello there,

This is something quite basic, but I am not sure on the proper way to go about setting up the static simulation study.

The situation is a simply hinged joint with each end pulling in opposite directions for simplicity sake. The two plates are fixed together with a pin which has 0.5mm hole clearance all around on both plates.

My question is around what is the best way to set this up so that it most accurately represents a real world situation.

My questions arise specifically around weather to use a pin or no pin (but then use a pinned constraint in the 3 cylinders), or to use a modeled pin, and use contacts to fix the pin in the places where I want to, or use a fixed constraint between the pin and the 3 cylinders?

It occurs to me, that if we were to use contacts, with a tolerance just above the amount that is the distance between the pin and 3 cylinders, so about 0.7mm, the pin would be bonded to the cylinders and not be representative of the real world, simply because the pin can not pull on the backside of the cylinder in an operating situation, but would do so in a bonded contact situation.

Can anyone give me some ideas or guidance here please?

Here is a simple model.

Hello there,

This is something quite basic, but I am not sure on the proper way to go about setting up the static simulation study.

The situation is a simply hinged joint with each end pulling in opposite directions for simplicity sake. The two plates are fixed together with a pin which has 0.5mm hole clearance all around on both plates.

My question is around what is the best way to set this up so that it most accurately represents a real world situation.

My questions arise specifically around weather to use a modeled pin, or no pin (but then use a pinned constraint in the 3 cylinders), or to use a modeled pin, and use contacts to fix the pin in the places where I want to, or use a fixed constraint between the pin and the 3 cylinders?

My issue is that if I were to use a bonded contact which allowed the modeled pin to be bonded to the 3 cylinders, it would not accurately represent whats happening in a real situation because the backside of the pin would not pull on the hole/cylinder, but in the bonded simulation, it would. I hope I am making this clear.

Can anyone give me some clarification or guidance on this please?

Here is the model: https://a360.co/3xHEZUx

Thanks

Joshua

[scastrophotography]

Hello,

Does anyone have any insights into this? Am I overthinking it?

Thanks

Joshua

[henderh · Accepted solution]

Hi @scastrophotography,

The modeled pin approach is the way to go. Using Pin constraints constrains the cylindrical face DOFs in space, much like a Fixed constraint would. 

I used a Separation contact type that'll allow compressive forces, but not tension, then moved the bodies so they're initially contacting each other (this can be done in the Simplify workspace without affecting the model in the Design workspace).

The setup provides realistic results if those two changes are made (model attached).

Stress result showing actual deformation:

With exaggerated deformation:

Contact forces on the pin:

[scastrophotography]

Thankyou Hugh, I appreciate your reply, it was very helpful.

I also just realised I wrote the same question twice in my original post, I accidental deleted most of it part way through and retyped it, it must have kept it somehow though haha.