Output Results Stresses 1

[Boghi1990]

Hi,

I have run a structural analysis to investigate the Circumferential, Radial & Axial Stresses in a pipe wall. In the stresses output results, there are listed several types of stresses(Von Mises Stresss, Principal Stresses and Tensor Stresses). Which of these do I need to look for in order to get the circumferential, radial and axial stresses?

Any suggestion or advice would be appreciated.

Regards,

One Point

 

[Boghi1990]

rb1957 (Aerospace),

You said:" i'd fully constrained the face axially (x?) and constrained one node in y and z and another (diametrically opposite) in z." and also " for this you need 3 (only) constraints ... 1 in y- and z- to react the forces and another in either y- or z- placed to react Mz (ie if you choose a 2nd y- it should be offset in z from the other y- constraint)..."

Reading the above comments I get a bit confused about how to correctly apply those nodal constraints. From what you have said, I need to use only two nodes. One node constrained in Y & Z and the other node constrained in eithe Y or Z. What about X direction?

Attached here is a print screen of the constraints I have assigned. One end(left) of the pipe (Node A) is constrained against Y & Z and the other end of the pipe (Node B) is constrained against Z.

What does it mean (" ie if you choose a 2nd y- it should be offset in z from the other y- constraint)..."? Why if I chose a 2nd Y, it needs to be offset in Z direction from the other y constraint?

 

[rb1957]

the first was a quote from the previous post (hence the "..."); I'm saying that the quote doesn't properly restrain rigid body motion.

we've clearly had a breakdown in communication ...

i'm surprised the model runs if you constrain just three freedoms (x, y, and z at a single node) ... somehow you or the FEA are constraining the other three freedoms (Mx,My,Mz).

i thought your previous post showed constraining every node in x, y, and z ?

Quando Omni Flunkus Moritati

 

[Boghi1990]

rb1957 (Aerospace),

I have run the structural analysis with the constraints as you suggested. Please see my previous post. I have got unrealitic displacement results in order of 187 inches magnitude. Attached here is a print screen of the displacement results. According to your suggestion (one node restrained against y and z, and the other node restrained against z), it looks like the thermal load applied to this pipe, causes the model to deform quite a lot in both y and z directions.

 

[rb1957]

it looks like you are constraining 3 freedoms (pinned) at two nodes which are in-line. this has two unintended side effects ...

1) you are constraining the length of the pipe (so it can't lengthen under load),
2) it doesn't constrain Mx (torque on the pipe) ... surprised it runs (again).

i suggest constraining the pipe with ...

1) x constraint on every node on face x = 0

2) (x,y,z) constraint at one node on face x = 0, say the bottom CL, like the point already constrained (yes?)

3) (x,z) constraint at one node on face x = 0, say the top CL

the idea is that 1) reacts Fx, My, and Mz; 2) and 3) react Fy, Fz, and Mx

Quando Omni Flunkus Moritati

 

[Boghi1990]

rb1957 (Aerospace),

I think I did not quite understand your suggestions. So, how many nodes I need to constraint ? Where these nodes have to be selected ? On face A of the pipe, on face B of the pipe or on both faces (A&B)?

What does it mean "1) x constraint on every node on face x = 0" ? What is "on face"?

What does it mean " (x,y,z) constraint at one node on face x = 0, say the bottom CL, like the point already constrained (yes?)"? What is CL?

What does it mean " (x,z) constraint at one node on face x = 0, say the top CL"?

Attached is the FEA model. I have marked up face A, the left end of pipe and face B the right end of pipe.