RE: C.O.G OF PIPES

From: <awolfe@muel.com>
Date: Tue Jun 01 2004 - 09:06:00 EDT

If you are using any AutoCAD based Piping design software it can easily be calculated. First get your piping into the neutral ACIS format. Perform the command MASSPROP and select the Piping that you want to know the COG of.
It will output something like this:

• SOLIDS ----------------

Mass: 8656.47243 lb
Volume: 8656.47243 cu in
Bounding box: X: 289.62640 -- 528.45536 in Y: 306.07426 -- 332.88676 in
Z: -5.50000 -- 5.50000 in
Centroid: X: 403.71350 in
Y: 310.79544 in
Z: 0.00000 in
Moments of inertia: X: 836374238.43652 lb sq in Y: 1454812878.88051 lb sq in
Z: 2291138653.50112 lb sq in
Products of inertia: XY: 1084846436.51312 lb sq in YZ: 0.00000 lb sq in
ZX: 0.00000 lb sq in
Radii of gyration: X: 310.83495 in
Y: 409.95208 in
Z: 514.46426 in
Principal moments (lb sq in) and X-Y-Z directions about centroid:

I: 173960.13929 along [0.99956 -0.02972 0.00000]
J: 43979940.70730 along [0.02972 0.99956 0.00000]
K: 44105437.03069 along [0.00000 0.00000 1.00000]

The Centroid is what you're looking for. The other information is not correct as AutoCAD ACIS solids do not take into effect density, material, etc. But the COG is correct.

Regards,

Aaron Wolfe
Piping Designer
Paul Mueller Company
P.O. Box 828
Springfield, Mo 65801
(417) 575-9780
E-mail: <a href="/group/PipingDesign/post?postID=-T8gt2t6AM7AW_aCFW4b3sqi1n_JOTYltNqB_tZVhYGiWA4X5n09tWLRmADTsvb_lrFwj3R1oKk">awolfe@muel.com</a>

-----Original Message-----
From: <a href="/group/PipingDesign/post?postID=B7jahjPJ2HHsnbieSQznEiAUp7uzXW-nzA5fuDGZ2QtGCQhC0ROjUFpx75H5YR9kcxhtRCMVntavBSjTEpG5K3xF">Jagarlamudi.Suresh@ril.com</a> [mailto:<a href="/group/PipingDesign/post?postID=B7jahjPJ2HHsnbieSQznEiAUp7uzXW-nzA5fuDGZ2QtGCQhC0ROjUFpx75H5YR9kcxhtRCMVntavBSjTEpG5K3xF">Jagarlamudi.Suresh@ril.com</a>] Sent: Tuesday, June 01, 2004 3:48 AM
To: <a href="/group/PipingDesign/post?postID=7kYcCHsORLrV7I9jFH9XESfVBZuX0MmP9xKmOYhoY3X7JWS3EfxZuUfplSmFqJCe1mdiU0hS-s32HaRp0wE_UpJqLTXA">PipingDesign@yahoogroups.com</a> Subject: Re: [PipingDesign] C.O.G OF PIPES

are you working on Caesar II or any other software? If you are working on Caesar II then you will get C.O.G of the system in different cases while checking of your error and warning report as well
as you will get this information in output report also. In output report it is in miscellaneous data as given below

CAESAR II  C.G. REPORT          FILE:DB057A00._P
                                Total Wght     X cg      Y cg      Z cg
------------------------------------------------------------------------
------
                                   (N. )      (mm.)     (mm.)     (mm.)
   Pipe                  :       616068.6   42072.5   49200.0  -30980.2
   Insulation            :            0.0       0.0       0.0       0.0
   Refractory            :            0.0       0.0       0.0       0.0
   Fluid                 :       966795.6   40285.5   49571.0  -30255.0
   Pipe+Insl+Refrty      :       616068.6   42072.5   49200.0  -30980.2
   Pipe+Fluid            :      1582862.6   40981.0   49426.6  -30537.3
   Pipe+Insl+Refrty+Fluid:      1582862.6   40981.0   49426.6  -30537.3

If you are not using Caesar II you can calculate it by manual calculations.
X =W1*x1+W2*x2+..../(W1+W2+...)
Y =W1*y1+W2*y2+..../(W1+W2+...)
X and Y are C.O.G point coordinates.

x1,x2,.. are x coordinates of C.G of each pipe segment.
y1,y2,.. are Y coordinates of C.G of each pipe segment.
W1,W2,... are weight of each segment.

The above is for 2D plane calculation like Same way we can calculate for 3D
with addition of Z coordinate to the above. In the above calculation you must consider all straight pipes,elbows and reducers.
For straight pipe C.G is at centre of the pipe. For 90 and 45 degree elbows it is interms of Radius. For finding the C.O.G in 3D you must draw different views in different planes and calculate it by using above said method.

I think this information may help you.
From
suresh.J

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Yahoo! Groups Links Received on Tue Jun 01 09:06:00 2004