Stress Concentration and Fatigue Analysis Quizzes - Machine Design

Question 1

Which of the following is NOT a factor influencing stress concentration?

Accepted Answer

Material yield strength

Answer

Geometric discontinuities

Answer

Loading conditions

Answer

Surface finish

Question 2

The stress concentration factor (Kt) is defined as:

Accepted Answer

The ratio of the maximum stress at the discontinuity to the nominal stress

Answer

The ratio of nominal stress to the maximum stress

Answer

The difference between the maximum and nominal stresses

Question 3

Which geometric discontinuity is most likely to cause stress concentration?

Accepted Answer

Sharp corner

Answer

Smooth fillet

Answer

Gradual taper

Answer

Rounded edge

Question 4

The fatigue life of a component is defined as:

Accepted Answer

The number of cycles to failure under a specified load

Answer

The time to failure under a specified load

Answer

The load at which failure occurs

Question 5

The S-N curve is a graphical representation of:

Accepted Answer

Fatigue strength versus number of cycles to failure

Answer

Stress versus strain

Answer

Load versus deflection

Question 6

Which of the following is a common fatigue failure mode?

Accepted Answer

Cracking

Answer

Buckling

Answer

Tearing

Answer

Melting

Question 7

The Goodman diagram is used to:

Accepted Answer

Predict fatigue life under combined static and alternating loads

Answer

Calculate fatigue strength

Answer

Determine stress concentration factors

Question 8

A stress concentration factor (Kt) is used to account for the increase in stress at a discontinuity in a component. Which of the following is NOT a common type of geometric discontinuity that can lead to stress concentration?

Accepted Answer

Smooth transition

Answer

Notch

Answer

Sharp corner

Answer

Hole

Question 9

Fatigue failure occurs when a material is subjected to repeated or fluctuating stresses. Which of the following factors does NOT significantly affect the fatigue life of a component?

Accepted Answer

Material yield strength

Answer

Stress ratio

Answer

Frequency of loading

Answer

Stress amplitude

Question 10

The S-N curve is a graphical representation of the fatigue strength of a material under varying numbers of cycles. Which of the following properties of the S-N curve is true?

Accepted Answer

The S-N curve is typically plotted on a logarithmic scale.

Answer

The S-N curve is independent of the material's yield strength.

Answer

The S-N curve provides an exact prediction of fatigue failure.

Answer

The S-N curve only applies to constant amplitude loading.

Question 11

Which of the following materials is generally known for its exceptional fatigue strength?

Accepted Answer

Titanium

Answer

Cast iron

Answer

Aluminum

Answer

Plastic

Question 12

Which of the following techniques can effectively extend the fatigue life of a component?

Accepted Answer

Reducing stress concentrations

Answer

Applying higher stress amplitudes

Answer

Lowering the material's yield strength

Answer

Increasing the number of loading cycles

Question 13

The Miner's rule is a widely used approach for estimating the fatigue life of components subjected to variable amplitude loading. Which of the following statements about the Miner's rule is correct?

Accepted Answer

The Miner's rule is based on the assumption of linear cumulative damage.

Answer

The Miner's rule considers the sequence of loading.

Answer

The Miner's rule applies only to constant amplitude loading.

Answer

The Miner's rule always provides an accurate prediction of fatigue life.

Question 14

In the context of stress concentration and fatigue analysis, which software tool is widely recognized for its capabilities?

Accepted Answer

ANSYS Mechanical

Answer

AutoCAD

Answer

Microsoft Excel

Answer

SketchUp

Question 15

A stress concentration factor (Kt) is used to account for:

Accepted Answer

The localized increase in stress at a geometric discontinuity

Answer

The material's yield strength

Answer

The average stress over the entire component

Question 16

The fatigue strength of a material is:

Accepted Answer

The maximum stress that a material can sustain without failure for a specified number of cycles

Answer

The ultimate tensile strength

Answer

The yield strength

Question 17

The Goodman criterion is used to predict fatigue failure when:

Accepted Answer

Both static and alternating stresses are present

Answer

The stress concentration factor is known

Answer

Only alternating stresses are present

Answer

Only static stresses are present

Question 18

Which of the following is a factor that affects fatigue life?

Accepted Answer

Material properties, geometry, loading conditions

Answer

Temperature only

Answer

Surface finish only

Question 19

The Miner's rule is used to:

Accepted Answer

Estimate the cumulative damage caused by multiple loading cycles

Answer

Reduce stress concentrations

Answer

Calculate the fatigue strength of a material

Question 20

Shot peening is a surface treatment used to:

Accepted Answer

Introduce beneficial compressive residual stresses

Answer

Decrease fatigue strength

Answer

Remove surface defects

Answer

Increase surface roughness

Question 21

Which of the following is a design consideration for components subjected to fatigue loading?

Accepted Answer

Avoiding sharp corners and sudden changes in geometry

Answer

Using brittle materials

Answer

Ignoring stress concentrations

Question 22

The stress concentration factor caused by a fillet is primarily influenced by which factor?

Accepted Answer

Fillet radius

Answer

Loading magnitude

Answer

Material yield strength

Answer

Surface roughness

Question 23

What is the significance of the Goodman diagram in fatigue analysis?

Accepted Answer

It provides a graphical representation of fatigue strength under varying mean stresses

Answer

It determines the fatigue life of a component

Answer

It predicts the fatigue limit of a material

Question 24

Which of the following is NOT a recognized type of fatigue failure?

Accepted Answer

Static failure

Answer

Torsional fatigue

Answer

Axial fatigue

Answer

Bending fatigue

Question 25

What is the primary purpose of using a fatigue strength reduction factor?

Accepted Answer

To account for uncertainties and variabilities in fatigue analysis

Answer

To simplify fatigue calculations

Answer

To increase the predicted fatigue life

Question 26

How do nominal stress and local stress differ?

Accepted Answer

Nominal stress is the average stress over a section, while local stress is the stress at a specific point

Answer

Local stress is always higher than nominal stress

Question 27

Why should stress concentrations be considered during design?

Accepted Answer

Stress concentrations can lead to premature failure

Answer

They are only relevant for complex geometries

Answer

They can improve fatigue life

Question 28

Which of the following is a common method for reducing stress concentrations?

Accepted Answer

Increasing fillet radii

Answer

Using sharp corners

Answer

Decreasing applied load

Question 29

What is the fundamental difference between fatigue failure and static failure?

Accepted Answer

Fatigue failure results from repeated loading below the yield strength, while static failure occurs due to a single high load

Answer

Fatigue failure only occurs in metals