Explanation:
(a) Formula for critical stress is as follows.
[tex]\sigma_{c} = \frac{k_{IC}}{\tau \sqrt{\pi \times a}}[/tex]
Here, [tex]K_{IC}[/tex] = 54.8
[tex]\tau[/tex] = 0.99
a = 0.8 mm = [tex]0.8 \times 10^{-3}[/tex] m
Putting the given values into the above formula as follows.
[tex]\sigma_{c} = \frac{k_{IC}}{\tau \sqrt{\pi \times a}}[/tex]
= [tex]\frac{54.8}{0.99 \times \sqrt{3.14 \times 0.8 \times 10^{-3}}}[/tex]
= 1107 MPa
Hence, value of critical stress is 1107 MPa.
(b) Applied stress value is given as 1205 MPa and since it is more than the critical stress (1107 MPa) as a result, a fracture will occur.
