Question

A cylindrical test specimen with a 15-mm diameter is tested axially in tension. A 0.58 mm elongation is recorded in a length of 200 mm when the load on the specimen is 36 kN. The material behaves elastically during testing. What material could the specimen be made of?a. Aluminumb. Magnesiumc. Polystyrened. Steel

Answer 1

Answer:

a. Aluminium

Explanation:

The strain of the specimen when tested

$\epsilon = \frac{\Delta L}{L} = \frac{0.58}{200} = 0.0029$

The area of the 15mm (0.015m) diameter specimen

$A = \pi(d/2)^2 = \pi(0.015/2)^2 = 0.000177 m^2$

So the stress when subjected to F = 36kN (36000 N) load is

$\sigma = F/A = 36000 / 0.000177 = 203718327.2Pa$

We can calculate the Young Modulus of the specimen

$E = \sigma/\epsilon = 203718327.2/ 0.0029 = 70247699020 Pa = 70.25 GPa$

This is Young Modulus of an Aluminium material