Answer:
Not subject to detection
Explanation:
Assuming the value of strain fracture toughness is 77 Mpa [tex]\sqrt m[/tex]
The design stress is half hence [tex]\sigma=0.5\times 1400=700 Mpa[/tex]
Critical flaw size, [tex]a_c=\frac {1}{\pi}(\frac {K_{1c}}{Y/sigma})^{2}[/tex]
Where Y is dimensionless parameter, [tex]\sigma[/tex] is applied stress, [tex]K_{1c}[/tex] is plane strain fracture toughness, [tex]a_c[/tex] is critical length of surface crack
[tex]a_c=\frac {1}{\pi}(\frac {77}{1*700})^{2}= 0.0038515496\approx 0.00385m[/tex]
The critical length of surface crack is therefore 3.85 mm, which is less than detection apparatus size given as 4 mm
Since the critical flaw size is less than the resolution limit of flaw detection apparatus, the critical flaw for this plate is not subjected to detection.
