Unsymmetric Multi Bore Pressure-containing component and how to constrain it?

Question

Unsymmetric Multi Bore Pressure-containing component and how to constrain it?

SiggiN (Marine/Ocean)

(OP)

11 Dec 20 12:08

Hi all!

I was wondering if anyone has a good (accurate) technique for constraining an unsymmetric multi bore pressure-containing component?

I've attachted an illustration of a model:

Suppose each bore can be pressurized independantly (load asymmetry). e.g. in one load case two bores have internal pressure, an other load case four bores have internal pressure and so on

The flat surface introduces geometrical asymmetry

I was thinking of using Inertial Relief, but i do not know the theory enough to know exactly what it does.

Any tips and tricks would be appriciated :)

(I've attached a step file of my example component)

Regards
Siggi

https://files.engineering.com/getfile.aspx?folder=2971212a-b543-49eb-bc47-0

FEA way (Mechanical) · Answer 1 · 2020-12-11 12:12:37

You should ask yourself a question how this part is constrained in real life ? If its motion is somehow restricted, you must represent these constraints in the analysis too. Of course some additional boundary conditions may be necessary to avoid rigid body motions in static analysis but the model should represent real life conditions as closely as possible.

Mustaine3 (Mechanical) · Answer 2 · 2020-12-11 15:34:06

The geometry is 2D-symmetric. When material properties and loading follow the same symmetry, then you can use this.

Some more hints on boundary conditions:
- there is a 3-node approach to apply BC on a self-balancing systems
- soft springs can be used
- damping/stabilization can also help

karachun (Mechanical) · Answer 3 · 2020-12-13 15:00:36

If pressure loads are balanced then you may use 3-2-1 method.

https://www.digitalengineering247.com/article/free...

rb1957 (Aerospace) · Answer 4 · 2020-12-16 18:47:44

presumably the faces are plate elements, so you could fix 1 node in all 6dof.

There are many ways to restrain the model for rigid body motion. It doesn't matter how you do this, it only affects the plane that the model will displace around.

FEA's post is regarding the physical restraint of the part. If the part cannot displace in a limited number of directions, then the model needs to be restrained the same way.

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Unsymmetric Multi Bore Pressure-containing component and how to constrain it?