Question

For a brittle material that has a specific surface energy of 0.33 J/m2, and flexural strength and elastic modulus values of 88.1 MPa and 61 GPa, respectively, calculate the critical stress (in MPa) required for the propagation of a surface crack of length 0.04 mm.

Answer 1

Answer:

critical stress = 17.899 MPa

Explanation:

given data

specific surface energy = 0.33 J/m²

flexural strength = 88.1 MPa

elastic modulus values E = 61 GPa

surface crack of length = 0.04 mm

to find out

critical stress (in MPa)

solution

we get here critical stress that is express as

critical stress = $\sqrt{\frac{2E\gamma}{\pi a}}$      .....................1

here E is elastic modulus values and a is surface crack of length and γ is specific surface energy

put here value we get

critical stress = $\sqrt{\frac{2*(61*10^9)*0.33}{\pi *0.04*10^{-3}}}$

critical stress = 1.7899 × $10^{7}$ N/m²

critical stress = 17.899 MPa