deflection, aluminum plate
deflection, aluminum plate
(OP)
I am trying to find out the deflection of a piece of 3/8" x 2" x 2" aluminum plate ( 6061 ) , with a point load of 225 lbs. It is supportated on all 4 sides.
Thanks
HBlake
Thanks
HBlake





RE: deflection, aluminum plate
RE: deflection, aluminum plate
Incidentally as it is a point load, the deflection is in fact infinite.
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: deflection, aluminum plate
Don't you mean stress is infinite ?
RE: deflection, aluminum plate
The theoretical stress would be infinite. Not deflection. I am sure it was just a typing error by Greg.
RE: deflection, aluminum plate
a 3/8" thick piece of Al, 2" square, will deflect just about 1/2 a gnat's hair under 225 lbs ...
if you want a precise number, Roark has lots of tables, try 11.4 case 1b (7th Ed). I suspect that you could approximate the problem as a simply supported (or doubly cantilevered) beam. for the simply supported case, this would give you a maximum moment of 225*2/4 = 112 in.lbs, and a stress of 112*6/0.375^2 = 4.8ksi and a deflection, if my math is right, of 5/16*(4.8/0.1875)*(2^2/1E7) = 0.003"
RE: deflection, aluminum plate
Garland E. Borowski, PE
Borowski Engineering & Analytical Services, Inc.
Lower Alabama SolidWorks Users Group
RE: deflection, aluminum plate
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: deflection, aluminum plate
-theoretical bending stresses become infinite at a concentrated load
-theoretical deflections remain finite at a concentrated load
-theoretical bending stresses at a concentrated load are not realistic, because the elementary bending theory for plates is not valid, as that theory assumes that the direct stress due to load application is negligible with respect to bending stress: a different treatment is required (see Timoshenko P&S point 19)
-deflections at a concentrated load as calculated by the elementary bending theory are realistic
prex
http://www.xcalcs.com
Online tools for structural design
RE: deflection, aluminum plate
though I concur with rb1957 on the low practical usefulness of your goal, you could use the calculation sheet available on the site below under Plates -> Bending+shear -> Rectangular -> Simply supported -> Conc.load
You'll see that the center deflection is 0.252 mils, where with simple bending that value is .206 mils.
rb1957 hope your fast calculated figures are incorrect, not the results of those sheets!
prex
http://www.xcalcs.com
Online tools for structural design
RE: deflection, aluminum plate
corus
RE: deflection, aluminum plate
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: deflection, aluminum plate
Hblake
RE: deflection, aluminum plate
RE: deflection, aluminum plate
What does an accurate description of the BC's count for once you have the pretty coloured result plot ? Depends what SIDE you are on.
RE: deflection, aluminum plate