Hi all, I'm currently doing a project and am tasked to design a rectangular chamber to withstand certain vacuum and/or positive pressure.

I've come up with the design. However now the issue is with simulations that I should be doing on the chamber.

Are there any rules or steps to ensure an accurate simulation?

I've been running a few iterations (following some steps I found online) and I'm not sure if I can trust the results. Though I'm rather certain it shouldn't fail since the pressure involved is low, but I'd like to have some accuracy to show for my report.

So generally, I would select a Static Study (I've seen some comments on doing a buckling study, but I've yet to look into it).

Then apply pressure on the inside/outer walls of the chamber (1bar vacuum or 3bar pressurised).

What I'd like to ask is:

1) Restraints. If my chamber is to be rested on a frame (not nailed or bolted), how do I restraint it? I've seen some comments suggesting Inertial Relief, but some other comments say it gives quite some error.

2) Mesh. I selected Standard mesh at 5mm. I understand I need to do mesh independence/convergence tests, but the max stress still trends upward while my computational power starts to suffer. Can't seem to reach a convergence point. I've seen suggestions to do H-adaptive studies. Is that a possible solution? Also, how would I know if the adaptive study reaches the percentage accuracy by the fifth iteration?

I've attached a picture of the chamber without its cover below.

Hi Eddie,

The setup you have created would not qualify for using the "Inertial Relief" option. That option requires that you have applied equal and opposite forces to the model such that the net force balances out to zero (SOLIDWORKS Help - Simulation: Inertial Relief). The pressure applied to the model is significantly non-zero in the -Z direction though. So, first thing to do is turn that option off.

Once you have that option off you need to think about how to stabilize the model in a way that does not adversely impact the results. Looking at your loading and the shape of the model this can readily be done by cutting out a corner of the model and applying 'Symmetry' fixtures to the resulting cut faces (GoEngineer - SOLIDWORKS Simulation: Symmetry Constraints). This would take care of stability for all rigid body translations/rotations except for the Z-direction translation.

Since you noted that this object is going to be set on a surface you would want to restrain the model by placing a 'Virtual Wall' contact condition for the model to push against (SOLIDWORKS Help - Simulation: Virtual Wall Contact). This stabilizes the Z-direction and lets the model then solve to completion.

It does look like you end up with a stress concentration (possibly a singularity) after 5 iterations of h-adaptive mesh. You may want to modify the geometry of the model in this place to have a fillet to help alleviate this as perfect sharp corners are not common for inside corners in manufacturing.

Attached is a modified model showing the setup itself.