Tensile strength:

What will be its ultimate tensile strength?

Solution

The condition for necking is = n = 0.3077

Hence using this value of, the true stress at necking

= 449.35 (0.3077)^0.3077

             = 449.35 × 0.696

 = 312.67 N/mm²

Hence maximum load, where, Au is the area of cross-section at P_u.

 Note

0.3077 = ln  (128.6144/ A_u)

∴          128.6144 / A_u  = 1.36

or         A_u = 94.55 mm²

∴        

                  = 312.67 × 94.55 N

                  = 29.6 kN

The ultimate tensile strength =  P_u / A₀  = 29.6 × 103 / 128.6144