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

0.05%

Step-by-step 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%