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

critical stress = 17.899 MPa

Step-by-step 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{(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{(2*(61*10^9)*0.33)/(\pi *0.04*10^(-3))}`

critical stress = 1.7899 ×
`10^(7)` N/m²

critical stress = 17.899 MPa