Fatigue analysis. Code stress instead equivalent stress.

Posted by: MynamePavel

Fatigue analysis. Code stress instead equivalent stress. - 05/11/22 02:09 AM

Good time for every body.

I have to do assessment by EN13480 that references to En13445. I selected ABS as combination method for all FAT load cases. If I look to FAT load case result as allowable circles number and check by S-N chart coresponded stress it is code stress but not 3D Max stress.

How to switch type stress for FAT analysis (from code stress to equvivalent)?
Posted by: MynamePavel

Re: Fatigue analysis. Code stress instead equivalent stress. - 05/11/22 02:11 AM

List of load cases:
Picture 1

Fat result:
picture 2
See load case 106
Node 1258
Allowable circles number is 1527

stress result:
picture 3
for same node.
According S-N chart 1527 circles correspond to 439830KPa
But in stress report it is next to code stress 453509KPa


CII options:
Picture 4
Posted by: Richard Ay

Re: Fatigue analysis. Code stress instead equivalent stress. - 05/11/22 08:26 PM

Sorry, we can't access your pictures - the Browser responds with "the site can't be reached".

However, the code stress for the FAT load cases is the 3D Max/Equivalent stress, regardless of the piping code used in the analysis. There is no need to switch anything.

If this doesn't help, please file a Support Request on Smart Support.
Posted by: MynamePavel

Re: Fatigue analysis. Code stress instead equivalent stress. - 08/01/22 06:07 AM

Hello,
I'm trying to do picture uploading again. As it is looks that I have same ptoblem now. See picture (stress in [kPa)]:

There is node 2438 where report "Cumulative Usage" gives to me allowable number of circle = 3593
Note all these events from 70 to 74 are fatigue and mention as FAT.

According S-N curve for N=3593 I have S=315950kPa


And then I check stress by "Stress Extended (Legacy)" for same node:

As it sown in the picture above the stress that has been used to find Nallow is not 3DMax but it is Code Stress.

And option:
Posted by: MynamePavel

Re: Fatigue analysis. Code stress instead equivalent stress. - 08/01/22 07:26 AM

And one more picture. This is "Cumulative Usage Extended"
where shown that 315949kPa used for FAT load case.

But as I post before it is code stress.