I have to design a hydraulic flange that has a minimum safety factor of 3 when a pressure of 500 bar is applied inside. see attached
I started with an EN-GJS-600-3 cast iron but I can't get the desired coefficient despite the many versions designed (increase of thickness in overstressed areas, addition of ribs, increase of fillets...).
As the results don't satisfy me (best social security coef obtained of about 2.3), I thought I would turn to other solutions. For example, an angled tube (made of steel for example) on which a collar would be welded at each end and which would be fixed with half flanges.
Do you have any other ideas or other solutions that you think could allow me to have a social security coef higher than 3?
I can't find the mechanical properties of the different materials used in 3D printing, especially steels... Do any of you have a link to share with me?
On design 2 I am less efficient because the maximum stress is no longer in the same place. The maximum stress was at the elbow in solution 1 and at the fillet fillet in solution 2.
Yes, I had seen this type of cast iron, but for economic reasons, I was forced to use a cast iron higher than EN-GJS-600 only as a last resort.
I can't justify the phenomenon concretely but when I add material in the elbow it increases the constraint in terms of connection leave. I think it's due to the fact that the cross-section decreases greatly at this level, which must cause a concentration of stress.
Again, I don't have any certainty, but that's the conclusion I came to when I saw the results.
I only went through the document quickly but did you try to reduce the section locally, towards the center of the pipe for example? What is the constraint in this area?
The idea is that the imposed displacement on Z creates a couple in the room. In the 1st case, I think that the max stress comes from the fact that the bending of the tube is combined with the pressure at the elbow. In the 2nd case, the elbow is so reinforced that the bending no longer occurs at this point but is transferred to flange 1 which therefore becomes the weak point. Hence the idea that perhaps by relaxing the bending of the tube on a less constrained area, it would perhaps make it possible to better distribute the stresses and therefore to improve the safety coeff.
The 0.5mm displacement is due to the dimensional tolerances of the parts on which the flanges will be attached.
Yes, I did the simuations without this imposed displacement and it logically reduces the constraints at the connection fillets, but it only slightly influences the stress at the elbow.