STEEL - Materials for Civil and Construction Engineers - page 131

testing machine, it was found that the specimen yielded at a load of
37.5 kips and fractured at 52.5 kips.
a. Determine the tensile stresses at yield and at fracture.
b. Estimate how much increase in length would occur at 60% of the
yield stress in a 2-in. gauge length.
3.18 A round steel alloy bar with a diameter of 0.5 in. and a gauge length
of 3.2 in. was subjected to tension, with the results shown in the
accompanying table. Using a computer spreadsheet program, plot
the stress-strain relationship. From the graph, determine the
Young's modulus of the steel alloy and the deformation correspond-
ing to a 8225-lb load.

Deformation,

10 - 4 in. Load, lb

2,000 11.28

4,000 22.54

6,000 33.80

8,000 45.08

10,000 56.36

12,000 67.66

3.19 Testing a round steel alloy bar with a diameter of 15 mm and a
gauge length of 250 mm produced the stress-strain relation shown
in Figure P3.19.

750

500

250

0

0 0.01 0.02 0.03 0.04

Strain, m/m

FIGURE P3.19

Determine
a. the elastic modulus
b. the proportional limit
c. the yield strength at a strain offset of 0.002
d. the tensile strength
e. the magnitude of the load required to produce an increase in
length of 0.38 mm
f. the final deformation, if the specimen is unloaded after being
strained by the amount specified in (e)