Beam Deflections Laboratory

Beam Deflections Laboratory

EMCH 361 Beam Deflections Laboratory  
An Old Student
September 4, 2002
Introduction
The purpose of the Beam Deflection Lab is to evaluate the mathematical model for forces
exerted on a simply supported beam and the deflection of that beam due to a point load at
the beams center. Experimental data will be compared to the theoretical expectations to
determine if the mathematical models are good approximations for determining load
distribution and beam deflection.
Experimental Procedures
The apparatus for this experiment consisted of two bathroom scales, two 2”x4” nominal
blocks, and one 2”x4” nominal 8’ board. The board was supported on the blocks, which
were positioned on the bathroom scales as shown in figure 1-1. Prior to setting up the
apparatus, the subjects weight was measured on both bathroom scales and recorded. After
stepping off the scales, zero was verified and the subject was weighed again to confirm
repeatability in our measurements. All four weights were averaged to determine the
subject’s weight (P) for the experiment.   The effective length of the 8’ board was
measured from the inside edge of one block to the inside edge of the other as illustrated
in figure 1-1 using a 25’ tape measure with 1/8
th
inch increments.
Once the initial conditions were met, the scales were adjusted to read zero with the
apparatus assembled so that the weight of the wood would not be measured. Several
points were marked on the board and the subject positioned himself so that his center of
mass was directly over each mark. The readings of both bathroom scales (R1 and R2)
were taken simultaneously then recorded. This was repeated at 8 additional points. The
data can be seen in Table 1-1. The theoretical expectations can be found in Table 1-2.
Figure 1-1
a
L
P
R1 R2
3.5”
1.5”This old lab report did not get an A grade for a number of reasons, including missing information in the
report and appendix and improperly...