| Applies To | |||
| Product(s): | AutoPIPE | ||
| Version(s): | 2004, XM, V8i, CONNECT; | ||
| Environment: | N/A | ||
| Area: | Modeling | ||
| Original Author: | Bentley Technical Support Group | ||
| Date Logged & Current Version | June. 2016 10.01.00.09 |
Problem:
How to model a pipe Strainer / Filter in Basket or Y-type configuration with AutoPIPE?
Solution:
In essence all of these piping components are model in similar ways using the procedure below:
Insert a 1.5 ft long component starting at node point B05, the weight of the piping component is 100 lbs, and weight of contents inside is 50 lbs. Flange connections are 300# rating. For analysis purpose, model has 4 Temperature / Pressure Load cases to be consider for design.
a. Set current node point to B05
b. Insert Slip-on flange set, 300# rating. "Insert Matting Flange" enabled
c. Insert Run to CG of the component, Length = 9", creating B06
d. Insert Run, Length = 9", creating B07
e. Insert Slip-on flange set, 300#.rating, "Insert Matting Flange" enabled
f. Select Node points B05 - B07, Insert > Rigid Options over Range, Include Weight = Disabled, Include Thermal Exp.= Enabled
g. Enter weight of Pipe Component
Here the user must use caution to ensure that the weight is correctly accounted for.
Options to apply piping component weight:
#1: Insert Weight at CG of the component
or
#2: Insert Distributed load over Range
Notes:
1. AutoPIPE calculates the content weight of an typical piping component by multiplying: (inner pipe diameter) x (length of component) x (Pipe Property Specific Gravity) x (Analysis Set Density Factor [default=1]).
2. With inserting "Rigid Options over Range" in step above, the total weight of the component + contents were removed from that section of piping:
Notice how the Pipe and Contents weight were reduced by that section where Rigid Properties were added.
3. Insert> Weight values are accounted for during the Gravity load case.
Both Methods have Pros and Cons. Therefore, in this exercise use Option #1> Insert Weight at CG of Component.
Method A:
Select the CG node point and insert multiple weights to account for different items (ex. Weight of Component, Weight of Contents, etc..)
a. Account for Weight of the component - Insert> Xtra Data> Additional Weight, vertical Dy = -100 lbs
b. Account for Weight of the contents - Insert> Xtra Data> Additional Weight, vertical Dy = -50 lbs
Question: According to the modeling approach above, is the component modeled weight too heavy? or is the weight correctly modeled at exactly 150 lbs?
Answer: Correct, the model component weight is too heavy. Remember how the flanges were modeled above, mating flanges were added, therefore there are 2 flanges who's weight has been added to this piping component. Solution, either change 1 flange at B05 & B07 equal to 0.00 lbs. Or, subtract the total weight of the flanges at B05 & B07 from weight of component.
c. Either change 1 flange at B05 & B07 equal to 0.00 lbs. Or, subtract the total weight of the flanges at B05 & B07 from weight of the component.
Method B:
Delete 1 flange from B05 & B07, and insert the total weight of contents and weight of the component all at one time.
a. Select CG of the component (ex. B06)
b. Account for total weight of the component & contents - Insert> Xtra Data> Additional Weight, vertical Dy = -150 lbs
Finished modeling the piping component.
Conclusion:
Modeling a Filter or Strainer component are fairly similar; model 2 sets of flanges on a section of piping to represent the Filter / Strainer body, insert rigid options over length (ignoring weight while considering thermal expansion), add a weight for Filter / Strainer body at the mid point, and add another weight at the same mid point for weight of Filter / Strainer contents.
This modeling approach does not automatically remove the contents weight of the Filter / Strainer if the "Contents " option is disabled in an analysis set. Remember, If one wants to run an analysis that does not consider weight of contents than delete the weight value from step G above before running an analysis. And, reapply this weight value when contents are to be considered in an analysis.
See Also
Model Different Types of PIPING Components