
∈ₙ= 0.20    σₙ = 575 MPa
K = 860 MPa
the true strain that results from the application of a true stress of 600 MPa (87,000 psi) IS ∈ₙ  = 0.24
Explanation:
Given that ,∈ₙ= 0.20    σₙ = 575 MPa
K = 860 MPa
When  σₙ= 575 MPa, what is ∈ₙ
Use ,  σₙ= K ∈ˣₙ  , solve for X
575 MPa = 860 MPa(0.20)Ë£
Take log of each side
log(575) = log860 - X log(0.20)
X = 0.25
Plug in X :
600 MPa = 860 MPa(∈ₙ )
X=0.25
∈ₙ =[tex](600/860)^{1/0.25}[/tex]
∈ₙ  = 0.24