To solve this problem it is necessary to apply the concepts related to stress failure, stress and last module Young.
Critical stress by definition is given as,
[tex]\sigma_c = \frac{K_{IC}}{Y\sqrt{\pi a}}[/tex]
Where,
[tex]K_{IC} =[/tex]Strain fracture toughness
Y = Young's module
a = Length surface crack
Our values are given as,
[tex]K_{IC} = 54.8Mpa[/tex]
[tex]Y = 1.11[/tex]
[tex]a = 0.8*10^{-3}m[/tex]
Replacing in our previous equation we have,
[tex]\sigma_c = \frac{54.8}{(1.11)\sqrt{\pi(0.8*10^{-3})}}[/tex]
[tex]\sigma_c = 984.77Mpa[/tex]
Therefore the critical stress is 984.77Mpa
