Question

The flow curve for a certain metal has parameters: strain-hardening

exponent is 0.22 and strength coefficient is54,000
lb/in2 . Determine:
a) the true stress at a true strain = 0.45
b) the true strain at a true stress = 40,000
lb/in2.

Answer 1

Answer:(a)
`45,300.24 lb/in/^2`

(b)0.255

Step-by-step explanation:

Given

Strain hardening exponent(n)=0.22

Strength coefficient(k)
`=54000 lb/in/^2`

and we know

`\sigma =k\left ( \epsilon \right )^n`

where

`sigma =true\ stress`

`\epsilon =true\ strain`

(a)True strain=0.45

`\sigma =54000* 0.45^(0.22)`

`\sigma =45,300.24 lb/in^2`

(b)true stress
`=40,000 lb/in^2`

`40000=54000* \epsilon ^(0.22)`

`\epsilon ^(0.22)=0.7407`

`\epsilon =0.7407^(4.5454)=0.255`