A 32mm rebar with a guage length of 200mm was subjected to tension to fracture according to ASTM E-8 method. The load and deformation data were as shown in table below.
Load(kn) Displacement(mm) Load Displacement
0 0 472.9 8.4
62.2 .1 487.1 9.7
188.9 .2 496.4 11.1
329.8 .4 505.7 12.4
383.4 1.7 512.8 13.7
426 4.0 522.6 15.3
447.3 5.9 532.4 18.5
462.5 7.2 525.9 22.4
a Using a spreadsheet program obtain the following:
a) a ;lot of the stress strain realtionship.
b) a ;oot of the linear portion of the stress strain relationship.
c) proprotional limit
d) yield stress
e) ultimate strength
f) if the rebar is loaded to 390kn only ad then unloaded, what is the premantnt change in length.