Which WRC 107/297 Parameters Should I Check and When Is My Geometry Valid for a WRC/297 Analysis?
Which WRC 107 or 297 parameters should I check? When is my
geometry valid for a WRC 107 or 297 analysis of a nozzle on
a pressure vessel subject to external loads?
These are questions that don’t have to be asked when the finite
element templates used for the nozzle calculations have been
used in ASME Code work and run more than 100,000 times.
FE107 also automatically compares 107 and 297 results against
the finite element analyses (FEA) so that users can know when 107
or 297 calculations are accurate enough.
From the comparison of FEA with WRC 107 and WRC 297 results it’s easy to
know if you should feel comfortable with a design.
The table below shows an example of the output.
|
Source |
Axial |
In-Plane |
Out-of-Plane |
Torsion |
|
FEA |
9.91 |
2.57 |
5.66 |
2.42 |
|
WRC 107 |
11.69 |
3.54 |
6.90 |
6.90 |
|
WRC 297 |
22.52 |
4.36 |
9.41 |
9.52 |
Comparison of FEA, WRC107 and WRC297 Stress Intensification Factors (SIFs)
In the example shown above, the WRC 107 and 297 results are too conservative,
with the 297 results being overly conservative by about two times as is often
the case. The conservatism or lack of conservatism is a function of the
geometry of the problem – which is why all critical analyses should be
checked.
FE107 also computes Stresses AND Allowables Loads.
FE107 Stress Plot Showing High Stress Location
Loads can be entered in local or global coordinates so that confusion does
not occur.
WRC 329 in Section 4.9 shows how the addition of a reinforcing pad to a
nozzle would actually increase the stress because the reinforcing pad
increases the stiffness, which increases the load more than the pad
reduced the stress.
FE/107 solves this problem by providing correct stiffnesses, stresses and
allowable loads.
Allowable Loads, Flexibilities, Stresses, ASME Output
AND
“Inspector Ready” Reports
Allowable loads and stiffnesses are calculated automatically
without any loads being input. If the loads are input, FE107
will produce ASME Code output.
Only four input values are required to generate allowable
loads, stress intensification factors and flexibilities –
the diameter of the nozzle and vessel, and the thickness of
the nozzle and vessel.
By Vessel Engineers – For Vessel Engineers!
Simple to Understand Nozzle Input AND Output
The input screen for FE107 is shown below:
FE107 was designed by vessel engineers for vessel engineers.
Anyone can put a square grid on intersection geometry these days,
but understanding element types, penetration line models, boundary
condition ovalization, beam load applications and Code stress calculations
is an entirely different matter.
FE107 has a one minute learning curve and takes about two minutes to run.
For less than US$1000, the vessel analyst gets exactly what he or she needs.
Various Geometries (with and without Pads)
- Cylinder-to-cylinder intersections
- Hillside Nozzles
- Laterals
- Elliptical Heads
- Hemispherical Heads
- Dished Heads
- Conical Heads
- Flat Heads
- Pad Reinforced Nozzles
- Barrel Shaped Nozzles
- Straight Nozzles
Diameters, wall thicknesses, nozzle angles and offsets are the
only inputs required to generate the above models.
Reinforcing pads and fillet weld sizes can also be entered.
Stresses per FEA and WRC Compared
If the stress is 10% of the allowable, then you can be off
by 10 times and still not have a problem. If the stress
is 100% of the allowable, then you cannot be off at all!
FE107 helps the user evaluate the criticality of a vessel nozzle geometry and the
load.
Load Definition is one of the biggest mistakes in
nozzle analysis!
Don’t get the load directions wrong!
FE107 load input is clear and uncomplicated.
Local and global definitions of loads are available,
along with pressure and varying temperature analyses.
(click on image to enlarge)
Material properties come into FE107 automatically
from MatPRO.
MatPRO – Materials for FE107 and much more!
FE107 links to the powerful and economically priced material database and
“condition calculator” MatPRO.
- How close a stress is to cyclic failure
- If creep-fatigue interaction is a concern
- Whether a crack, corroded, or eroded area satisfies API 579 Fitness for Service Rules
MatPRO features are listed on the
MatPRO product page.
MatPRO lets you enter stresses from CAESAR,
Ansys, or any other program! Read more about using MatPRO.
FE107 results are easy to understand and use.
Stresses are classified by location in the model.
ASME Allowable values are color coded for easy
identification. 3D plots animated results for
each ASME Code stress category are available with
the click of a button.
Graphics You Can Use!
FE107 graphic engine was designed by the first
Microsoft® VIP for DirectX® and Tony Paulin,
and was designed for pressure vessel and
piping geometries.
Rotate, pan and zoon animated displaced shape models
while viewing static or dynamic stress states.
Stresses beyond certain limits may be shown, arrows
and sprites can be used to show the highest stress
state and a variety of other interrogation tools are
available.
The FE107 animated graphics is the fastest way possible
to review and validate finite element output results.
Inspector Ready Reports
The key to any analysis is communicating the results
to others.
It’s not just good enough to “know” the system is OK,
a concise, easy to understand report must make that
clear to the inspector and the owner. FE107
generates automatic reports
with figures and graphics showing input values, FEA plots and
colorized stress tables.
GEOMETRY INPUT
=======================================================
Dimensions for Cylindrical Shell
Outside Diameter D = 33 [in.]
Wall Thickness T = 1 [in.]
Dimensions for Unreinforced Branch
Branch Diameter d = 12 [in.]
Branch Wall Thickness t = 1 [in.]
Start with No Obligation!
A SHAREWARE version of FE107 is available on the
PRG website
that includes WRC 107 and WRC 297 capability without the FEA.
The SHAREWARE download is smaller than 5Mb and can be
emailed anywhere.