WOOD - Materials for Civil and Construction Engineers - page 441

Table P10.19

10 3 in.

Load (lb) Deflection ( )

0 0

100 27.9

200 55.6

300 83.2

400 111.2

500 140.0

600 166.7

700 194.3

800 222.2

900 250.1

1000 275.4

1100 314.8

1200 359.5

1300 405.0

1400 468.6 (failure)

a. Using a computer spreadsheet program plot the load-deflection re-
lationship.
b. Plot the proportional limit on the graph.
c. Calculate the modulus of rupture (flexure strength).
d. Does the modulus of rupture computed in (c) truly represent the ex-
treme fiber stresses in the specimen? Comment on the assumptions
used to compute the modulus of rupture and the actual response of
the wood specimen.
10.20 A wood specimen was prepared with actual dimensions of
and grains parallel to its length. The specimen was sub-
jected to compression parallel to the grains to failure. The load-de-
formation results are as shown in Table P10.20.
a. Using a computer spreadsheet program, plot the stress-strain
relationship.
b. Calculate the modulus of elasticity.
c. What is the failure stress?
10.21 A pine wood specimen was prepared with dimensions of
and grains parallel to its length. The
specimen was subjected to compression parallel to the grains to
failure. The load-deformation results are as shown in Table P10.21.
a. Using a computer spreadsheet program, plot the stress-strain re-
lationship.
b. Calculate the modulus of elasticity.
c. What is the failure stress?

1 in. *

1in. * 4 in.

50 mm * 50 mm * 200 mm