the mid point of elbow

Dear all ,

When I model one stanchion / trunnion support from the mid point of elbow , ie: Node 10-20 (20 is defined as a bend) then Node 19 to 1000 (node 19 is mid point of elbow and node 1000 is trunnion support) ; however , I find the coordinate for node 1000 is same as node 20 , from my understanding the coordinate @ node 1000 should be different with node 20 and it should be indicated to be similiar with node 19 ~

Could somebody give me any idea about this issue ?

Thanks & Regards,
YFH

My setup is 8"NS LR elbow that is 1' x 1', starting at 0,0,0. It is node 10-20-30. If I attach a 1' base support to it at node 19-1000, the coordinate for node 1000 is 1',-1',0, whereas node 20 is 1',1',0.

Double check your nodes to make sure you're not using them redundantly.

Dear sir ,

Thanks for your kindly response ; I would like to know that node 19 is defined as mid point of elbow, then as per your case study , the coordinate for node 1000 should be 0.36',-1',0 since the offset 0.36' is a real mid point location of 8" LR elbow , isn't it ?
I am just curious why I can't find the coordinate for mid point of elbow even I have already designed a base support from this point ?

While I hate to use the phrase, it's "because that's how it's done." It is more economical at this time and has lower risk associated with conforming to historical work practices, by and large.

When the construction group lays out how they are going to put out the pipe, they use string to indicate placement, and elbows are replaced with 90° angles. They measure from that point, but know they will need to leave extra to account for this, and cut off the extra amount they don't need when it's time to install it. (Because that's how they do things, that's why drafting specifies the piping thusly, and because that's how drafting does it, CAESAR follows along.)

From a stress standpoint, Dave has demonstrated that using the standard work practice for estimating stresses is sufficiently similar to "actual" stress calculations that it typically does not merit the extra effort used to specify precise dimensions.

Now, if you're installing an elbow base support on the space station made using hastelloy, wrapped in sheets comprised of carbon nanotubes, dipped in the platinum melted from King Ferdinand XXII's crown, you would have understandable reason to be able to specify such a specific length.

yes, you are right.

but the question

"why I can't find the coordinate for mid point of elbow even I have already designed a base support from this point ?"

is still pending....

the question is about software working, not about "real world"

Vermaccio,

It is not a feature in the software because it was not deemed necessary to perform the role of stress analyst for the reasons listed.

Hi Michael ,

As Vermaccio said that this is about software working and it seems not hard to add and list the coordinate for mid point of elbow in Caesar II program. While somebody who starts to learn or review the input file , this question may be always happened and this is why I am curious about this issue.

Thanks & Regards,
YFH

CAESAR II lists coordinates of nodes for entered node numbers only. Entered nodes appear in the From or To fields. This does not include the nodes developed around a bend. You see coordinates of the Tangent Intersection Point but not the bend beginning, end and midpoint.

I think this is what you want. Feel free to check the math.

Blue indicates input. Green indicates output.

If you need a specific angle, use solver to change the offset to meet that angle.

so: the output data "L branch (CL-Base)" indicates the lenght from "bottom of trunnion" to "the intersection point between trunnion vertical axe and elbow lower surface"?

If yes: if bottom of trunnion has an absolute elevation "K",
the absolute elevation of "intersection point between trunnion vertical axe and elbow lower surface" will be K+"L branch (CL-Base)".


question: what is "NS"? and what unit lenght have we to use? inch or mm?

"NS" should read "Nominal Size." It determines overall size of the elbow. E.G. a Long Radius 8" NS elbow is 12" long from CL of inlet to CL of outlet, despite having an OD of 8.625". I'm not thoroughly familiar with metric piping, as long as NS•Elbow Radius = CL to CL dimensions of the fitting, the dimensions will work out. The spreadsheet is otherwise blind to units. Use mm, cm, in, ft, km, etc, as long as you're consistent.

Offset pushes the branch left (-) and right (+) from this view.

L branch (CL-Base) should be read as "Length of branch connection from base to extrados along the branch centerline."

L branch (Outer Edge-Base) should be read as "Length of branch connection from base to extrados along the longest edge of the branch."

L branch (inner Edge-Base) should be read as "Length of branch connection from base to extrados along the shortest edge of the branch."

Elevation of the horizontal pipe minus "K" is this spreadsheet's input "L". Note again, that "L" must be same units as NS and OD, if you modify this input to be the difference of elevations.

Perhaps this will be easier to read.

thank you

I checked result for inch and mm dimensions.

- inch calculus is correct.
- mm calculs is NOT correct.

the problem is in nominal size.
example:
in english we have 8".
In metric we have 200mm but 8"*25.4=203.2mm and all small differences due to unit conversions cause wrong result.

So is better to use the inch measures.

i made an excel check, how can i attach it here?

Use the full "Reply" option, there is a "File Manager" link at the bottom of the form.

Then I would suggest replacing NS value with 1, and the bend radius with CL CL length of elbow.

Hi Michael,

Appreciated your kindly effort really~

Hi Dave / Richard,

As per the content of CII webinar "Modeling and evaluating bends with attachments" , it can be built an "offset" element from the mid point of bend (by CII default value) to model the attachment ; I think it is meaningful to list/show the coordinate for mid point of bend , isn't it ?

Regards,

here the check i made.
- 1st sheet: inch
- 2nd sheet: mm

in every sheet there is an (autocad) drawing referred to excel calculus (for 8" elbow and 62 trunnion).

As you can see the "inch" calculus is ok but the "mm" calculus isn't.

Vermaccio,

You input "L" incorrectly on the mm tab.