- #1

WillemBouwer

- 81

- 1

I have to run a FEA analysis on a nozzle check valve body DN700... Its been to a professional engineer and he has completed the study so I am trying to do it myself to get to know the software better... I'm using PTC CREO 2 mechanica as the software...

Attached find a picture of the valve body.

I have constaint the valve at the hole locations on the flanges, as pin constaints. Where the angular constraint is free and the axial constraint is fixed.

The valve is rated at 40 bar, therefor should be tested at 1.5 time working pressure so 60 bar... So the load I used was a pressure load on the surfaces of the entire inside of the body for full open condition, and on the surfaces up to the point where the disc should close the flow off for the fully closed condition.

I would like to analize the valve in both fully open and fully closed conditions. With the disc of the valve pressing against the diffuser and the body when fully open, and pressing against the centre piece and the body at fully closed position...

I have set the material to be SG42 Cast iron and meshed the body...

At fully open condition I get the Maximum Von Mises stress to be 224 MPa at the bolted area

At fully closed condition I et the Maximum Von Mises stress to be 221 MPa on the fins of the body...

However a picture of the professional engineers findings have been attached. He finds the Max Von Mises stress to be 312.5 MPa which differs from my analysis.

Now the question is: Why is his stress more, what am I not thinking about? Can anyone help please, thanks... It is complex to explain what I did but ask eny questions, haha...

Attached find a picture of the valve body.

I have constaint the valve at the hole locations on the flanges, as pin constaints. Where the angular constraint is free and the axial constraint is fixed.

The valve is rated at 40 bar, therefor should be tested at 1.5 time working pressure so 60 bar... So the load I used was a pressure load on the surfaces of the entire inside of the body for full open condition, and on the surfaces up to the point where the disc should close the flow off for the fully closed condition.

I would like to analize the valve in both fully open and fully closed conditions. With the disc of the valve pressing against the diffuser and the body when fully open, and pressing against the centre piece and the body at fully closed position...

I have set the material to be SG42 Cast iron and meshed the body...

At fully open condition I get the Maximum Von Mises stress to be 224 MPa at the bolted area

At fully closed condition I et the Maximum Von Mises stress to be 221 MPa on the fins of the body...

However a picture of the professional engineers findings have been attached. He finds the Max Von Mises stress to be 312.5 MPa which differs from my analysis.

Now the question is: Why is his stress more, what am I not thinking about? Can anyone help please, thanks... It is complex to explain what I did but ask eny questions, haha...