I'm getting a max. stress where it doesn't quite make sense to me. I've got an internal pressure of 15,000 psi, and I'm assuming all the nozzles are fixed (welded). It's showing a max. stress where I wouldn't expect. Any thoughts?
Constraints
Loads
Results
Did you run it with convergence? What's the mesh look like in that area?
Also, there's a lot of interpretation required with something like this. Frequently, you'll see weirdness in tiny little pinprick areas, and a lot of the time those are just quirks of the way the mesh was generated rather than an actual problem area in the part design.
Upload the assembly and the models, we'll take a look.
Rusty
You've modeled this as a single monolithic part. Is that actually the case, or are the 4 small nozzles along the side separate items that are pressed into place and then welded? This will make a difference in how your part gets analyzed.
Rusty
Okay.
The problem I think is your fixed constraints. Because you're essentially supporting the slope on each nozzle in a rather absolute fashion but not supporting the sides of the nozzle, you're seeing a knife edge of high stress where the support ends.
Based on what I see here in your part, it looks like you've got the flat surface on top there with the intent of having that whole area - the flat and the nozzles - be fully supported?
Rusty
@Anonymous wrote:
I was trying to simulate that it would be a complete weld at that place...like a weldolet. So the sloped area and flat area would be constrained/welded. I'll check that, but I believe they are both currently constrained. Are you saying that's an issue?
I'm not necessarily saying it's a problem with your design - I don't know all your specs or anything - but I'm saying that by defining those surfaces as fixed entities, the part will not perform in FEA the same way that it will in the real world. Your support with a fixed constraint is absolute. There is no give. In the real world, your support piping is going to be subject to the same forces and heat expansion, etc., that the manifold is under, and it's all going to be flexing and deforming in the same way. Your set of fixed constraints do not - cannot - simulate that.
Rusty
Thank you. I noticed this later (i missed pressure at bottom of hole 1) as I was trying to fix things...i've changed it somewhat...I was going to run the simulation on the following piece....
@TheCADWhisperer wrote:
A couple of things I noticed -
you did not apply the pressure to the conical face at the bottom of the Hole1.
you have gone well beyond the linear elastic deformation (a limitation of Inventor FEA) into plastic deformation.
you have not installed the latest Service Pack and Updates for your version of Inventor.
Good catch on the hole bottom, but I'm not positive you're correct about the plastic deformation. Most of the super high stress areas I'm seeing are due to mesh singularities or issues with the constraints.
(Or, if you are, then it's a design issue - this is steel, so if you're past the yield strength then you've got other problems.)
Rusty
That's probably the way I'd do it. I'd probably make the piece of pipe the length they actually will be, too, and you don't need to bother capping those ends, probably. You can just fix the end of the pipe. (That said, if the pipe is actually capped off it probably wouldn't hurt anything.)
Rusty
It looks like you have applied a custom material properties - I didn't look it up, but be sure the Sy is correct.
