"Leak before break" (LBB) means that the crack must be able to grow through the wall thickness before unstable rupture of pressure vessel. An engineer tries to design a pressure vessel that is capable of withstanding a static pressure and that will "leak-before-break". The required material has a fracture toughness of and a yield strength of 586 MPa. The diameter of the vessel is specified to be 1.2 m with a wall thickness of 12.5 mm. A crack with surface length of 15 mm can reliably be detected.
(1) Confirm that the pressure vessel will leak before burst when the surface length of the crack is smaller than this size by calculating the maximum size of the surface crack that can develop and still maintain the LBB criteria.
(2) Explain briefly the importance of the precision of surface crack detection using LBB criterion.