John P
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| posted on 15/8/06 at 04:25 PM |
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Help - Second Moment of Area
I need to calculate the buckling load for a vertically mounted hydraulic cylinder in accordance with an agreed formulae from a British Standard.
Trouble is I need the Second Moment of Area of the cylinder rod in 4th power milimetres.
Sounds easy but I'm getting confused.
The cylinder rod is 60mm diameter.
Thanks,
John.
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RazMan
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| posted on 15/8/06 at 04:54 PM |
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quote:
Originally posted by John P
Sounds easy but I'm getting confused.
You're confused - that goes way beyond my City & Guilds Engineering Certificate! You lost me after the word 'calculate'
 
[Edited on 15-8-06 by RazMan]
Cheers,
Raz
When thinking outside the box doesn't work any more, it's time to build a new box
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Aboardman
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| posted on 15/8/06 at 05:18 PM |
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is this any good
Area: 2827.4334
Perimeter: 188.4956
Bounding box: X: -30.0000 -- 30.0000
Y: -30.0000 -- 30.0000
Centroid: X: 0.0000
Y: 0.0000
Moments of inertia: X: 636172.5124
Y: 636172.5124
Product of inertia: XY: 0.0000
Radii of gyration: X: 15.0000
Y: 15.0000
Principal moments and X-Y directions about centroid:
I: 636172.5124 along [0.7071 0.7071]
J: 636172.5124 along [-0.7071 0.7071]
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TangoMan
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| posted on 15/8/06 at 05:36 PM |
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quote:
Originally posted by Aboardman
is this any good
Area: 2827.4334
Perimeter: 188.4956
Bounding box: X: -30.0000 -- 30.0000
Y: -30.0000 -- 30.0000
Centroid: X: 0.0000
Y: 0.0000
Moments of inertia: X: 636172.5124
Y: 636172.5124
Product of inertia: XY: 0.0000
Radii of gyration: X: 15.0000
Y: 15.0000
Principal moments and X-Y directions about centroid:
I: 636172.5124 along [0.7071 0.7071]
J: 636172.5124 along [-0.7071 0.7071]
That's just what I was going to say 
Summer's here!!!!
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jon_boy
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| posted on 15/8/06 at 05:44 PM |
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some one else has to retake somecourse work then?!
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matt_claydon
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| posted on 15/8/06 at 07:23 PM |
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Second moment of area for a solid circular section is (Pi)*(r^4)/4.
Using your diameter of 60mm this gives
Ixx = Iyy = 636200 mm^4
HTH,
Matt.
[Edited on 16/8/06 by matt_claydon]
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Aboardman
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| posted on 15/8/06 at 07:49 PM |
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quote:
Originally posted by matt_claydon
Second moment of area for a solid circular section is (Pi)*(r^4)/4.
Using your diameter of 60mm this gives
Ixx = Iyy = 10180000 mm^4
HTH,
Matt.
are you sure on the answer
pi * (30^4) / 4 =636172.51235
easy way to check second moment of any shape if you have autocad.
draw your shape, box circle, i beam, some fancy shape what ever you want.
make it a closed polyline, then turn the shape into a region, by using the region command.
then by using the tools/inquiry/region mass properties this will give you the values i gave before, however this is incorrect, you then need to reset
the ucs to the Centroid of the object. so that the values for the centroid are x0,y0
once you have done this redo the mass properties and there you go.
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matt_claydon
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| posted on 16/8/06 at 07:29 AM |
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Yep, thanks for pointing that out - small mistake on my part ; corrected now!
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Simon
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| posted on 17/8/06 at 12:24 AM |
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quote:
Originally posted by RazMan
You lost me after the word 'calculate'
Lost me after the word Help
ATB
Simon
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