I need to determine the loads on a pump suction nozzle, but there is a very long radius bend with a horizontal dummy leg right next to it. I am confused about the input of this dummy leg. Is anyone willing to see if I have done this correctly? My file is attached, as well as a drawing that I used to double check the offset dimensions. I just want to see if I have my signs correct for the offset and for the dummy leg element length.

Also, I do not have FE-Bend, so what is the next best way to estimate the SIF, or do I even need to worry about this?

Thanks in advance.

Hi Trevor,

Did you ever hear anything back on this? I'm interested in hearing thoughts on this as well.

FEBend will only go up to a 18.8125" bend radius for these diameters. At that radius and temperature, I got the following results:

Stress Intensification Factors

Branch/Nozzle Sif Summary

Peak Primary Secondary
Bend In : 1.918 1.865 3.687
Bend Out: 1.819 1.694 2.905
Trun In : 1.452 1.280 2.151
Trun Out: 1.378 1.109 2.042
Pressure: 5.337 9.823 10.673

B31 CODE
Peak Stress Sif .... 1.710 Inplane
1.456 Inplane Single Flange
1.241 Inplane Double Flange
1.425 Outplane
1.214 Outplane Single Flange
1.034 Outplane Double Flange

FEA SIF’s

There are primary, secondary and peak Stress Intensification Factors. The first are the SIF’s due to primary loads, the second one is due to secondary loads and the third one is due to peak stresses. The Peak SIF’s are the ones that need to be entered in a beam analysis program like CAESAR II.

I would use the highest SIF for both inplane and outplane for both bend and trunnion because I don't believe Caesar properly applies the two and is dependent on your model orientation.

BEND FLEXIBILTIY FACTORS:

Shell finite element flexibility factors printed below
consider the effect of the attached pipe, and the optional
welded staunchion. Ki, Ko values printed should be entered
directly into a beam type pipe stress program. The CODE
Ki, Ko factors were computed using h = (tR/r^2), and
K = 1.65 / h. Additional factors are for one and two ends
flanged respectively.

FE Computed Ki = 3.210
FE Computed Ko = 3.510
Single Double
CODE Computed Ki = 4.321 3.681 3.135
CODE Computed Ko = 4.321 3.681 3.135


The values below are the ratios of the shell finite element
rotations at the trunion ends due to inplane and outplane
moments to the beam-type rotations at the trunion ends due
to the same moments. Ratios greater than 100% indicate that
the shell model is more flexible than an equivalent beam
model. The beam model assumes that the trunion pipe
connects to the horizontal weldline on the bend.

Inplane Bending Ratio = 24.471 %

Outplane Bending Ratio = 6.486 %

Peak
Bend In : 1.918
Bend Out: 1.819
Trun In : 1.452
Trun Out: 1.378
Pressure: 5.337

Dears

If any one can help for review the caesar input where i has the same problem.

Best regards

Dears,

I found a good information a bout this topic in old post titled by "offset method".

Best Regards