Simulation of hydraulic press plates

[jpC2NLM]

Good day all,

I am stuck with an issue which I'm not quite sure how to solve with the Simulation functionality.

I have a hydraulic press where I am pressing 2 extremely thin materials in-between two Aluminium plates to fuse them. This process needs to be up-scaled. I would need to determine the plate thickness I would need to have the least possible displacement (in other words, I need to determine the plate thickness to have the most uniform pressure applied across the entire plate section). The plates outer dimensions are 430x340mm, inner hole (hole is for the press piston to reside) 3mm deep with 53mm diameter. I have used 10, 15 and 20mm thickness but can't seem to get my settings in order on the Simulation Workspace.

What I have tried:

1. A Static Stress Study with the following: A load with a force of 29 500N applied in the middle of the plate where the hydraulic press would be applying pressure and the constraint as the bottom of the plate.

2. A Static Stress Study with the following: A load with a pressure of 13.5MPa applied in the middle of the plate as well as at the bottom of the plate with the constraints as the outer 4 faces on the plate.

3. A variety of the above mentioned with different faces selected as constraints etc.

All results seem unreasonable and the thicker the plate the more displacement I get in the middle without any idea of what effect it has towards the outer edges of the plate as curling/bowing is bound to happen.

Any help is welcomed! Thank you in advance.

[jpC2NLM]

The hydraulic press I am using:

[TheCADWhisperer]

Can you File >Export and then Attach your *.f3d file here?

[jpC2NLM]

Thanks! Please find file attached.

[TheCADWhisperer]

Rather than the Extruded "divot" in the top of the plate - I would use Split Face.

I would also Split Face on the other side of the plate for the contact of the material.

Look at the problem in reverse by applying reaction force.

The circular split face Fixed, and the (reaction) load applied on the rectangular split face on other side opposite of the hydraulic ram.

I will post example later today.

Here is my first example (without splitting the rectangular face on bottom.

[jpC2NLM]

That is a great idea. I do however want to indent the plate to ensure the piston always finds the center position. Your advise and help is much appreciated.

[tyler_henderson]

A couple of other things to consider:

• If the plates are thin then you might need to use a finer mesh.  As a general rule, you should try to have at least 3 mesh elements through the thickness of the plate.  Fusion Simulation doesn't have Shell elements yet, so a fine mesh is the only option right now.
• Try Nonlinear Stress.  If the pressure/stress is going beyond the Yield Stress of the material then it likely won't behave linearly.

[jpC2NLM]

Thanks for the information @tyler_henderson, you have a good point. I will give it a go as well!

[Anonymous]

A thicker plate should deflect more in the middle than a thinner plate.

If you're seeing significant deflection, you need to run non-linear. 

You also need to make sure you are using separation contacts on the plate interfaces that you expect bowing. This is going to allow the surfaces to actually lift instead of bonding them together. 

I didn't look at your file so I'm not sure what all you've already done.

[jpC2NLM]

Thanks @Anonymous I have not made contacts like such but will also see if I could get my head around it.