beam/plate in bending, is there a difference? 2

[PEinOHIO]

if i have a plate in bending (simply supported, force applied at the center), 15ft long, 5 ft wide, 1 inch thick, can i use standard beam bending formulas or is there a correction factor if it is more of a plate then a beam?

 

[rb1957]

L^4 is a pretty wicked term ...
i get hokie'd 1.6" for 180" length, and 0.27" for 115"

d = 12/30E6*5/384*0.3*L^4, assuming t = 1"

 

[hokie66]

It is tricky to measure self load deflection, as initial curvature comes into it. For the 68 pound load at centre span, I get 0.84", not too far from what you measured.

 

[desertfox]

I get a deflection 1.6mm for a plate 15ft * 5Ft and 1" thick.
I used this formula out of Mechanical engineers handbook by Carvill:-

ym = k1*Pa^2/E*t^3 where t=thickness 1"

P= point load at centre of plate
acting over a small radius

a= plate width
b= plate length
k1= b/a

 

[rb1957]

i suspect that's the formula for a plate simply supported on four sides, and is P representing the weight of the plate ... which'd be about 1.5 tons