Wooden Cantilever Beam

 

Experiment

Measure the deflection at two points, x=a and x=b, on the beam with dial gages as a function of load.  Plot deflection y versus load P and determine the slope of the lines.

 

Theory

 

Results

Assume theoretical y/P ratio and experimental y/P ratio are equal at "a" and "b" and solve for E at both places.  Use the following as reference values.

Common
Species Name
 Modulus of
Elasticity (Msi)
cedar 1.1
pine 1.5
oak 1.5
poplar 1.6
red oak 1.8
douglas fir 1.8
if not specified 0.9 to 1.8
averaged from US-grown, 12% moisture-content values in
Wood Handbook Chapter 4 - Mechanical Properties of Wood
  • June 2006, Lowes
  • 1"x3"x6' poplar $5.88
  • 1"x3"x6' red oak $8.44
  • 1"x3"x6' Douglas fir $3.53