GATE MT Fracture behaviour, Griffith theory, linear elastic fracture mechanics, fracture toughness, fractography, ductile to brittle transition. PYQs & Answers

Questions 1–10 of 10. Imported answers require independent review unless marked reviewed.

Which one of the following graphs represents Griffith’s criterion for the growth of a crack in a brittle isotropic infinite large plate with a center crack?

In the graph,

is the magnitude of the total strain energy released (shown by solid curve) and

is the total surface energy (shown by dashed line) and

is the critical crack length (shown by downward arrow) at which the crack starts growing. The tangent to the

curve parallel to the

line is shown by the dotted line.

Your answerChoose one option.

Diagram for Metallurgical Engineering question 45

Diagram for Metallurgical Engineering question 45 (figure 2)

Diagram for Metallurgical Engineering question 45 (figure 3)

Diagram for Metallurgical Engineering question 45 (figure 4)

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

A large rectangular component is undergoing fully-reversed cyclic loading, and the component is known to grow the dominant fatigue crack from the outer surface. If the stress amplitude (

) is 100

and the critical stress intensity factor

of the material is 50

then the crack length at which the component will fail catastrophically is _____

. (Round off to one decimal place)

Given: The geometric factor

for this loading condition is 1.12.

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

When cracks propagate in a brittle material, the following option(s) is/are correct

Your answerSelect all correct options. You can choose more than one.

elastic strain energy decreases

surface energy increases

surface energy decreases

elastic strain energy increases

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

With reference to the stress intensity factor, find the correct match of nomenclature (Column A) with the mode of deformation applied to the crack (Column B).

Column A: (P) Mode I (Q) Mode II (R) Mode III

Column B: (X) Forward shear mode (Y) Parallel shear mode (Z) Crack opening mode

Your answerChoose one option.

P – Z, Q – Y, R – X

P – Z, Q – X, R – Y

P – Y, Q – X, R – Z

P – Y, Q – Z, R – X

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

An infinite metal plate has a central through-thickness crack of length

mm. The maximum applied stress (in MPa) that the plate can sustain in mode I is: __________ (round off to nearest integer). Assume: Linear elastic fracture mechanics is valid Given: Fracture toughness,

MPa m

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

A component subjected to tensile stress in a mechanical device is monitored periodically for cracks by NDT. The NDT technique can only detect cracks (both surface and internal) which are larger than 1 mm. Keeping a 10% margin of safety, the maximum allowed tensile stress on the component will be _____ MPa (round off to the nearest integer).

Given, fracture toughness

and assume crack geometry factor of unity.

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

The length of internal cracks in two samples of the same glass is measured to be

and

. The ratio

of the fracture strength of the two samples is ____________.

Your answerChoose one option.

0.5

1.0

2.0

4.0

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

A glass fibre of 5 micron diameter is subjected to a tensile stress of 20 MPa. The surface energy and elastic modulus of this material are 0.3 Jm

and 70 GPa, respectively. Pick the correct answer based on the information provided above:

Note: The glass fibre contains a population of flaws of different lengths.

Your answerChoose one option.

The fibre will undergo brittle fracture

The fibre will undergo plastic deformation, but not fracture

The fibre will undergo elastic deformation, but not fracture

The fibre will undergo buckling

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

A brittle material (Young’s modulus = 60 GPa and surface energy = 0.5 J.m⁻²) has a surface crack of length 2 μm. The fracture strength (in MPa) of this material is __________ (answer up to two decimal places)

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

A perfectly elastic-plastic material has a yield stress of 450 MPa and fractures at a strain of 0.45. The ratio of resilience to toughness for this material is ________ (answer up to three decimal places)

(Given the Young’s modulus E = 4.5 GPa)

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

GATE MT Fracture behaviour, Griffith theory, linear elastic fracture mechanics, fracture toughness, fractography, ductile to brittle transition. PYQs

How to practice Fracture behaviour, Griffith theory, linear elastic fracture mechanics, fracture toughness, fractography, ductile to brittle transition.

Question 45

Question 63

Question 26

Question 29

Question 49

Question 22

Question 19

Question 29

Question 16

Question 52