Answer :
Answer:
0.234
Explanation:
True stress is ratio of instantaneous load acting on instantaneous cross-sectional area
σ = k × (ε)^n
σ = true stress
ε = true strain
k = strength coefficient
n = strain hardening exponent
ε = ( σ / k) ^1/n
take log of both side
log ε = [tex]\frac{1}{n}[/tex] ( log σ - log k)
n = ( log σ - log k) / log ε
n = (log 578 - log 860) / log 0.20 = 0.247
the new ε = ( 600 / 860)^( 1 / 0.247) = 0.234
Answer:
The true strain that results from the application of a true stress of 600 MPa, will be 1.25.
Explanation:
The relation between true stress and true strain is given by the following formula:
σ = K (ε)^n
First, we find the value of n by substituting the values found by first test:
σ = 578 MPa
K = 860 MPa
ε = 0.2
Therefore,
578 MPa = (860 MPa)(0.2)^n
0.2^n = 0.67209
taking ln on both sides:
n ln(0.2) = ln(0.67209)
n = -0.3973/ln(0.2)
n = -1.6
Now, for the new stress value of 600 MPa, we calculate the strain:
600 MPa = (860 MPa)(ε)^-1.6
(ε)^1.6 = 1.4333
Taking power 1/1.6 on both sides, we get:
ε = 1.25