Question

Consider a mild steel specimen with yield strength of 43.5 ksi and Young's modulus of 29,000 ksi. It is stretched up to a point where the strain in the specimen is 0.2% (or 0.002). If the specimen is unloaded (i.e. load reduces to zero), the residual strain (or permanent set) is: 0.05% 0.1% 0% 0.2%

Answer 1

Answer:

0.05%

Explanation:

From the question, we have;

The yield strength of the mild steel, $\sigma _c$ = 43.5 ksi

Young's modulus of elasticity, ∈ = 29,000 ksi

The total strain, $\epsilon _c$ = 0.2% = 0.002

The inelatic strain $\epsilon_c^{in}$ is given as follows;

$\epsilon_c^{in}$ = $\epsilon _c$ - $\sigma _c$/∈

Therefore, we have;

$\epsilon_c^{in}$ = 0.002 - 43.5/(29,000) = 0.0005

Therefore, the inelastic strain, $\epsilon_c^{in}$ = 0.0005 = 0.05%

Taking the inelastic strain as the residual strain, we have;

The residual strain = 0.05%