The elastic portion of the stressstrain diagram for an alumi

The elastic portion of the stress-strain diagram for an aluminum alloy is shown in the figure (Figure 1). The specimen from which it was obtained has an original diameter of 12.7 mm and a gage length of 49.3 mm. When the applied load on the specimen is 40 kN, the diameter is 12.67494 mm. Determine Poisson\'s ratio for the material. Express your answer to three significant figures and include appropriate units.

Solution

Poisson\'s ratio = Lateral strain/ longitudinal strain

Lateral strain = change in dia/ original dia= 0.02506/12.7=0.00197323

Longitudinal strain = 0.007 from graph

Poissons ratio = 0.00197323/0.007= 0.28188