Answer:
we are supposed to determine the stress level at which a wing component on an aircraft will fracture for a given toughness of [tex]37 MPa\sqrt{m}[/tex] and maximum internal crack length [tex]1.29 mm[/tex] , given that fracture
occurs for the same component using the same alloy at one stress level [tex]206 Mpa[/tex] and another internal crack length (2.58 mm). It first becomes necessary to solve for the parameter Y for the conditions under which fracture occurred , therefore
[tex]Y=\frac{K_{lc} }{sigma\sqrt{\pi a } }[/tex]
[tex]=(37Mpa\sqrt{m} )/(206Mpa)\sqrt{\pi \frac{2.58*10^-^3m}{2} } \\=2.82[/tex]
[tex]sigma_{c} =K_{lc} /Y\sqrt{\pi a }[/tex]
[tex]=(37MPa\sqrt{m} )/(2.82)\sqrt{\pi \frac{1.29*10^-^3}{2} } \\= 293 MPa[/tex]
