Solution Manual for Shigleys Mechanical
Engineering Design 11th Edition Budynas /
All Chapters 1 - 20 / Full Complete 2023
Section 1: Fundamentals of Design (Chapters 1-4)
1. Which of the following are primary considerations in the "Design for Manufacture and
Assembly" (DFMA) methodology? (SATA)
A. Minimizing the number of parts
B. Using exotic, high-performance materials
C. Designing for ease of handling and insertion
D. Maximizing the complexity of individual components
Correct Answers: A, C
Rationale: DFMA focuses on simplifying the product structure to reduce cost and assembly
time. This is achieved by minimizing part count (A) and making parts easy to handle and insert
(C), often by making them self-aligning. Using exotic materials (B) increases cost, and
maximizing complexity (D) is the opposite of the goal.
2. A mechanical design engineer is calculating the factor of safety for a ductile material. The
material's yield strength is known, and the maximum stress in the part is well-defined. Which
failure theory is most appropriate for this scenario?
A. Maximum Normal Stress Theory
B. Maximum Shear Stress (Tresca) Theory
C. Distortion Energy (von Mises) Theory
D. Modified Mohr Theory
Correct Answer: C
Rationale: The Distortion Energy (von Mises) theory is generally the most accurate and
widely used theory for predicting the yielding of ductile materials. It correlates well with
experimental data for most ductile metals. The Maximum Shear Stress theory is more
conservative but less accurate.
3. What is the primary purpose of a "factor of safety" in engineering design?
A. To make the design more expensive
B. To account for uncertainties in loads, material properties, and manufacturing
C. To ensure the part will fail at a predictable load
D. To satisfy a purely academic requirement
, Correct Answer: B
Rationale: The factor of safety is a design margin that accounts for unavoidable
uncertainties. These include variations in the applied load, inconsistencies in material
properties, manufacturing tolerances, and the consequences of failure.
4. A steel rod is subjected to an axial tensile load. The cross-sectional area is 200 mm², and
the applied load is 50 kN. Calculate the normal stress in the rod.
A. 100 MPa
B. 250 MPa
C. 400 MPa
D. 50 MPa
Correct Answer: B
Rationale: Normal stress (σ) is defined as force (F) divided by area (A). σ = F/A = 50,000 N /
200 mm² = 250 N/mm² = 250 MPa.
5. Which of the following are examples of a static load? (SATA)
A. The weight of a bridge structure on its supports
B. The force exerted by a car on a road during a crash
C. The tension in a cable supporting a stationary elevator
D. The load on a gear tooth as it rotates
Correct Answers: A, C
Rationale: A static load is one that is applied slowly and does not change in magnitude or
direction over time. The weight of a bridge (A) and the tension in a stationary cable (C) are
constant. A crash (B) is a high-impact dynamic load, and a rotating gear tooth (D) experiences a
fully reversed or fluctuating load.
6. A component is made of a material with a yield strength of 400 MPa and an ultimate tensile
strength of 550 MPa. The maximum von Mises stress in the component is 200 MPa. What is
the factor of safety against yielding?
A. 1.5
B. 2.0
C. 2.75
D. 0.5
Correct Answer: B
Rationale: The factor of safety against yielding (ny) is the ratio of the yield strength (Sy) to
the maximum stress (σ). ny = Sy / σ = 400 MPa / 200 MPa = 2.0.
7. In the context of materials selection, what does the term "endurance limit" refer to?
A. The stress at which a material will fail after one cycle
,B. The stress level below which a material has an infinite fatigue life
C. The maximum stress a material can withstand before yielding
D. The stress at which a material becomes perfectly plastic
Correct Answer: B
Rationale: The endurance limit (Se) is a property of certain materials, like steel, where the
S-N curve becomes horizontal. Below this stress level, the material can theoretically withstand
an infinite number of fatigue cycles without failing.
8. A shaft is subjected to a torque of 150 N·m. The shaft has a diameter of 25 mm. Calculate
the maximum torsional shear stress.
A. 48.9 MPa
B. 24.4 MPa
C. 97.8 MPa
D. 12.2 MPa
Correct Answer: A
Rationale: The maximum torsional shear stress (τ) is given by τ = Tc/J, where T is torque, c is
the outer radius, and J is the polar moment of inertia. For a solid shaft, J = πd⁴/32.
τ = (150 N·m * 0.0125 m) / (π * (0.025 m)⁴ / 32) = 1.875 / (3.835e-8) ≈ 48.9e6 Pa = 48.9 MPa.
9. Which of the following statements about the "stress concentration factor" (Kt) are true?
(SATA)
A. It is a theoretical factor based on geometry.
B. It is always greater than or equal to 1.
C. It is only relevant for static loading.
D. It is reduced by the material's notch sensitivity.
Correct Answers: A, B, D
Rationale: The theoretical stress concentration factor Kt is a function of geometry (A) and is
always ≥ 1 (B). For fatigue, it is modified by the notch sensitivity factor (q) to find the fatigue
stress concentration factor Kf (D). It is critical for fatigue (dynamic) loading, not just static (C is
false).
10. A cantilever beam of length L is subjected to a point load F at its free end. Where does the
maximum bending stress occur?
A. At the free end
B. At the midpoint
C. At the fixed support
D. It is uniform along the beam
Correct Answer: C
Rationale: The bending moment is maximum at the fixed support (M = F*L) and zero at the
, free end. Since bending stress is proportional to the bending moment, the maximum stress
occurs at the fixed support.
11. What is the primary difference between "static" and "fatigue" failure?
A. Static failure occurs at a lower stress level.
B. Fatigue failure occurs after many cycles of fluctuating stress.
C. Static failure is more common in rotating machinery.
D. Fatigue failure only occurs in brittle materials.
Correct Answer: B
Rationale: Static failure occurs when a single application of load causes stress to exceed the
material's strength. Fatigue failure occurs after a large number of stress cycles, even if the
maximum stress is well below the yield strength.
12. A material has a Poisson's ratio of 0.3. If it is subjected to an axial strain of 0.001, what is
the lateral strain?
A. 0.0003
B. -0.0003
C. 0.003
D. -0.003
Correct Answer: B
Rationale: Poisson's ratio (ν) is the negative ratio of lateral strain to axial strain: ν = -ε_lat /
ε_ax. Therefore, ε_lat = -ν * ε_ax = -0.3 * 0.001 = -0.0003. The negative sign indicates
contraction.
13. Which of the following are valid methods for reducing stress concentration in a machine
part? (SATA)
A. Adding a fillet with a larger radius
B. Drilling a hole near the stress concentration
C. Using a sharper corner
D. Adding a relief groove
Correct Answers: A, B, D
Rationale: Stress concentrations can be reduced by making the geometry change more
gradual. A larger fillet radius (A) is a primary method. Adding a hole (B) or a relief groove (D) can
redistribute stress away from the critical area. A sharper corner (C) would dramatically increase
the stress concentration.
14. A bolt is tightened to a preload of 10 kN. The bolt has a stiffness of 200 kN/mm and the
members have a stiffness of 800 kN/mm. If an external load of 5 kN is applied, what is the
resulting force in the bolt?
Engineering Design 11th Edition Budynas /
All Chapters 1 - 20 / Full Complete 2023
Section 1: Fundamentals of Design (Chapters 1-4)
1. Which of the following are primary considerations in the "Design for Manufacture and
Assembly" (DFMA) methodology? (SATA)
A. Minimizing the number of parts
B. Using exotic, high-performance materials
C. Designing for ease of handling and insertion
D. Maximizing the complexity of individual components
Correct Answers: A, C
Rationale: DFMA focuses on simplifying the product structure to reduce cost and assembly
time. This is achieved by minimizing part count (A) and making parts easy to handle and insert
(C), often by making them self-aligning. Using exotic materials (B) increases cost, and
maximizing complexity (D) is the opposite of the goal.
2. A mechanical design engineer is calculating the factor of safety for a ductile material. The
material's yield strength is known, and the maximum stress in the part is well-defined. Which
failure theory is most appropriate for this scenario?
A. Maximum Normal Stress Theory
B. Maximum Shear Stress (Tresca) Theory
C. Distortion Energy (von Mises) Theory
D. Modified Mohr Theory
Correct Answer: C
Rationale: The Distortion Energy (von Mises) theory is generally the most accurate and
widely used theory for predicting the yielding of ductile materials. It correlates well with
experimental data for most ductile metals. The Maximum Shear Stress theory is more
conservative but less accurate.
3. What is the primary purpose of a "factor of safety" in engineering design?
A. To make the design more expensive
B. To account for uncertainties in loads, material properties, and manufacturing
C. To ensure the part will fail at a predictable load
D. To satisfy a purely academic requirement
, Correct Answer: B
Rationale: The factor of safety is a design margin that accounts for unavoidable
uncertainties. These include variations in the applied load, inconsistencies in material
properties, manufacturing tolerances, and the consequences of failure.
4. A steel rod is subjected to an axial tensile load. The cross-sectional area is 200 mm², and
the applied load is 50 kN. Calculate the normal stress in the rod.
A. 100 MPa
B. 250 MPa
C. 400 MPa
D. 50 MPa
Correct Answer: B
Rationale: Normal stress (σ) is defined as force (F) divided by area (A). σ = F/A = 50,000 N /
200 mm² = 250 N/mm² = 250 MPa.
5. Which of the following are examples of a static load? (SATA)
A. The weight of a bridge structure on its supports
B. The force exerted by a car on a road during a crash
C. The tension in a cable supporting a stationary elevator
D. The load on a gear tooth as it rotates
Correct Answers: A, C
Rationale: A static load is one that is applied slowly and does not change in magnitude or
direction over time. The weight of a bridge (A) and the tension in a stationary cable (C) are
constant. A crash (B) is a high-impact dynamic load, and a rotating gear tooth (D) experiences a
fully reversed or fluctuating load.
6. A component is made of a material with a yield strength of 400 MPa and an ultimate tensile
strength of 550 MPa. The maximum von Mises stress in the component is 200 MPa. What is
the factor of safety against yielding?
A. 1.5
B. 2.0
C. 2.75
D. 0.5
Correct Answer: B
Rationale: The factor of safety against yielding (ny) is the ratio of the yield strength (Sy) to
the maximum stress (σ). ny = Sy / σ = 400 MPa / 200 MPa = 2.0.
7. In the context of materials selection, what does the term "endurance limit" refer to?
A. The stress at which a material will fail after one cycle
,B. The stress level below which a material has an infinite fatigue life
C. The maximum stress a material can withstand before yielding
D. The stress at which a material becomes perfectly plastic
Correct Answer: B
Rationale: The endurance limit (Se) is a property of certain materials, like steel, where the
S-N curve becomes horizontal. Below this stress level, the material can theoretically withstand
an infinite number of fatigue cycles without failing.
8. A shaft is subjected to a torque of 150 N·m. The shaft has a diameter of 25 mm. Calculate
the maximum torsional shear stress.
A. 48.9 MPa
B. 24.4 MPa
C. 97.8 MPa
D. 12.2 MPa
Correct Answer: A
Rationale: The maximum torsional shear stress (τ) is given by τ = Tc/J, where T is torque, c is
the outer radius, and J is the polar moment of inertia. For a solid shaft, J = πd⁴/32.
τ = (150 N·m * 0.0125 m) / (π * (0.025 m)⁴ / 32) = 1.875 / (3.835e-8) ≈ 48.9e6 Pa = 48.9 MPa.
9. Which of the following statements about the "stress concentration factor" (Kt) are true?
(SATA)
A. It is a theoretical factor based on geometry.
B. It is always greater than or equal to 1.
C. It is only relevant for static loading.
D. It is reduced by the material's notch sensitivity.
Correct Answers: A, B, D
Rationale: The theoretical stress concentration factor Kt is a function of geometry (A) and is
always ≥ 1 (B). For fatigue, it is modified by the notch sensitivity factor (q) to find the fatigue
stress concentration factor Kf (D). It is critical for fatigue (dynamic) loading, not just static (C is
false).
10. A cantilever beam of length L is subjected to a point load F at its free end. Where does the
maximum bending stress occur?
A. At the free end
B. At the midpoint
C. At the fixed support
D. It is uniform along the beam
Correct Answer: C
Rationale: The bending moment is maximum at the fixed support (M = F*L) and zero at the
, free end. Since bending stress is proportional to the bending moment, the maximum stress
occurs at the fixed support.
11. What is the primary difference between "static" and "fatigue" failure?
A. Static failure occurs at a lower stress level.
B. Fatigue failure occurs after many cycles of fluctuating stress.
C. Static failure is more common in rotating machinery.
D. Fatigue failure only occurs in brittle materials.
Correct Answer: B
Rationale: Static failure occurs when a single application of load causes stress to exceed the
material's strength. Fatigue failure occurs after a large number of stress cycles, even if the
maximum stress is well below the yield strength.
12. A material has a Poisson's ratio of 0.3. If it is subjected to an axial strain of 0.001, what is
the lateral strain?
A. 0.0003
B. -0.0003
C. 0.003
D. -0.003
Correct Answer: B
Rationale: Poisson's ratio (ν) is the negative ratio of lateral strain to axial strain: ν = -ε_lat /
ε_ax. Therefore, ε_lat = -ν * ε_ax = -0.3 * 0.001 = -0.0003. The negative sign indicates
contraction.
13. Which of the following are valid methods for reducing stress concentration in a machine
part? (SATA)
A. Adding a fillet with a larger radius
B. Drilling a hole near the stress concentration
C. Using a sharper corner
D. Adding a relief groove
Correct Answers: A, B, D
Rationale: Stress concentrations can be reduced by making the geometry change more
gradual. A larger fillet radius (A) is a primary method. Adding a hole (B) or a relief groove (D) can
redistribute stress away from the critical area. A sharper corner (C) would dramatically increase
the stress concentration.
14. A bolt is tightened to a preload of 10 kN. The bolt has a stiffness of 200 kN/mm and the
members have a stiffness of 800 kN/mm. If an external load of 5 kN is applied, what is the
resulting force in the bolt?
