If the specific surface energy for magnesium oxide is 1.0 J/m2 and its modulus of elasticity is (225 GPa), compute the critical stress required for the propagation of an internal crack of length 0.3 mm.

Answers

Answer:

The critical stress required for the propagation of an initial crack = 21.84 M pa

Explanation:

Given data

Modulus of elasticity E = 225 ×

Specific surface energy for magnesium oxide is = 1

Crack length (a) = 0.3 mm = 0.0003 m

Critical stress is given by = ——– (1)

⇒ 2 E = 2 × 225 × × 1 = 450 ×

⇒ a = 3.14 × 0.0003 = 0.000942

⇒ Put these values in equation 1 we get

⇒ =

⇒ = 4.77 ×

⇒ = 2.184 ×

⇒ = 21.84

⇒ = 21.84 M pa

This is the critical stress required for the propagation of an initial crack.

Answer:The critical stress required for the propagation of an initial crack= 21.84 M paExplanation:Given data

Modulus of elasticity E = 225 ×

Specific surface energy for magnesium oxide is = 1

Crack length (a) = 0.3 mm = 0.0003 m

Critical stress is given by=——– (1)⇒ 2 E = 2 × 225 × × 1 = 450 ×

⇒ a = 3.14 × 0.0003 = 0.000942

⇒ Put these values in equation 1 we get

⇒

=⇒

= 4.77 ×⇒ = 2.184 ×

⇒ = 21.84

⇒= 21.84 M paThis is the critical stress required for the propagation of an initial crack.