Applies To
Product(s):	AutoPIPE
Version(s):	ALL;
Environment:	N/A
Area:	Modeling
Original Author:	Bentley Technical Support Group
Date Logged & Current Version	Oct. 2016 10.01.00.09

Problem:

How to model a vertical vessel held in place by 4 supports in AutoPIPE?

Example:

 

Solution:

In this example, Start with a Vertical Pipe, and add the vessel to the top of it using the following process:

Note: this procedure assumes that all the correct pipe properties are already assigned in the model.

Step #1: Make Vertical pipe node point the current point. 

Step #2: Insert Flange Set. (ex. B04)

Step #3: Insert pipe to bottom of vessel (ex. B05)

Step #4: Insert Vessel piping (Outside Dia = 60 in) from bottom of vessel to same height as the vertical location of the 4 Vessel supports. (ex. B06)

Step #5:  Insert Vessel piping from support height to top of vessel. (ex. B07)

Step #6: Set previous node point as the current node point (ex. B06)

Step #7: insert Segment 

Set Tee Type to Other, SIF = 1.0 in/out of plane

Note: During model consistency check the following warning may appear " W726-10:  User SIF required at junction  at following point(s)". Setting the SIF as shown above takes care of this. However the warning may still remain. Another precaution would be to insert a User SIF at this location and to Over ride all other SIFs as indicated below

 

Step #8: Insert a pipe run in the direction towards a support location, length would be distance from center of vessel to outside surface of the vessel. (ex (ex. B06 to C01, Dx = 30in)

 

Repeat 3 more times.

(ex: Seg D - Dz = 30in, Seg E - Dx = -30in, Seg F - Dz = -30in)

Note - make sure before inserting a new segment that the active point is B06 on the vessel piping and not B06 on the branch piping. See the lower right corner of the application screen to see the current Node point, current Segment, and current PIPE id.

Internal vessel piping is segment C with Pipe Id = 8sch40.

Vessel is segment B  with Pipe Id = Tank,

Note: Do not use Beams from the center of the vessel  to the outside surface. 

Step #9: Select last 4 inserted pipes as pictured above and Insert> Rigid Options Over Range> 

Step #10: At this point make a decision

Option #1: Assume the vessel is rigidly supported at this surface location

or

Option #2: Take credit for steel properties from outside surface of vessel to actual support location

Choose option #1 or Option #2 ??? 

Selected Option #1:

At each of the 4 support locations (ex. C01, D01, E01, F01) insert an rigid anchor.

Done!!

Selected Option #2:

At each of the 4 support locations (ex. C01, D01, E01, F01) perform the following:

a. Insert Beams with correct properties as needed from surface of vessel to support location.

b. Insert supports as needed to mimic type of support, 

For instance

- Slotted support to allow thermal growth of vessel

- Restrained to move left, right, up or down relative to local directions

- etc..

In this example only added beam with V-stop support.

 Done !!

In conclusion:

Most vessels with one or multiple connections supported in various ways can be approximately modeled in AutoPIPE with a little effort.  It is important to make it clear that the results of the piping used to model the vessel from the piping analysis should be ignored. Modeling the vessel as an equivalent pipe is only useful to take into account the movement of the connection point between the vessel and the pipe due to different loadings. 

See Also

Beam Structure modeling

Bentley AutoPIPE