What is the magnitude of the maximum stress that exists at the tip of an internal crack having a radius of curvature of 3.5 × 10-4 mm (1.378 × 10-5 in.) and a crack length of 4.5 × 10-2 mm (1.772 × 10-3 in.) when a tensile stress of 170 MPa (24660 psi) is applied?

Respuesta :

Given:

applied tensile stress, [tex]\sigma[/tex] = 170 MPa

radius of curvature of crack tip,  [tex]r_{t}[/tex] =  [tex]3.5\times 10^{-4}[/tex] mm

crack length = [tex]4.5\times 10^{-2}[/tex] mm

half of internal crack length, a = [tex]\frac{crack length}{2} = \frac{4.5\times 10^{-2}}{2}[/tex]

a =  [tex]2.25\times 10^{-2}[/tex]

Formula Used:

[tex]\sigma _{max} =  2\times\sigma \sqrt{\frac{a}{r_t}}[/tex]

Solution:

Using the given formula:

[tex]\sigma _{max} = 2\times170 \sqrt{\frac{2.25\times 10 ^{-2}}{3.5\times 10^{-4}}}[/tex]

[tex]\sigma _{max}[/tex] = 2726 MPa (395372.9 psi)