FEA results with ABSA and ASME

[davidlee97]

Hello,

I'm working on analysis report for PED certificate, and I got some questions as following,

1. ABSA AB520 require "Plot with element stress and compare nodal (average) stress vs. element (non-average) stress (should <5%)". Is this to check the max. stress nodal and elment or some interested elements because some max. stress located at contact area, tip top or edge and those are non-critical theoretically. On the other side, I didn't find how to get all nodal stress of an element with Solidworks Simulation.

2. ASME 2007 shows the Linearization after FEA. If nowhere stress larger than general membrane stress, do I need to do linearization?

3. Traditionally, the report need to show the safety factor which is the ratio of allowable value and calculated value according to ASME VIII Div1, But FEA is following Div2 and no specification about safety factor there, do I need to calculate them? What's the ratio of?

I appreciate your great help!

David

 

[TGS4]

Have you ever performed an FEA to Division 2, Part 5? Is this your first time?

 

[davidlee97]

Hi TGS4,

Yes. It's the first time to run FEA per Div 2. That's why got some questions.

Thanks!

David

 

[TGS4]

I highly recommend that you search the archives in this forum. There have been many discussions around performing FEA for pressure vessels.

MY personal recommendation to you is to find yourself a mentor, work with them for the next year or two, until you feel a little more confident in performing these types of analyses. Take a Div. 2 class. Attend the ASME PVP Conference. Read as many papers as you can on the subject.

I have been doing this for many years now, and I have trained several engineers on this exact topic. On average, I would estimate that it takes about a year of closely-monitored experience until I am comfortable in having an engineer that I have trained to work independently on FEA for pressure vessels. It takes at least another year before they feel adequately prepared. It's a complex field that requires in-depth knowledge of the mathematics behind FEA, knowing your software, and a thorough understanding of pressure vessels. I call this my analogy of the three-legged stool. If you're missing any one of those three, you're left with a two-legged stool...

I would also recommend that you purchase and read ASME PTB-1-2009 (

http://catalog.asme.org/Codes/PrintBook/PTB1_2009_Section_VIII.cfm).

I would add WRC 429 to your reading list as well.

 

[Crompto29]

Check out

http://www.pveng.com.

It has plenty of FEA examples and guidelines. There is a worked example that answers your question 2.