Machine Design Questions and Answers – Fracture Mechanics, Curved beams & Thermal Stresses

This set of Machine Design Multiple Choice Questions & Answers (MCQs) focuses on “Fracture Mechanics, Curved beams & Thermal Stresses”.

1. Stress intensity factor is the critical value of stress at which crack extension occurs.
a) True
b) False
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2. The critical value at which crack extension occurs is called
a) Stress Intensity Factor
b) Toughness
c) Fracture Toughness
d) None of the mentioned
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3. Fracture toughness does not depend upon geometry of the part containing crack
a) True
b) False
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4. How many modes are there for crack propagation?
a) 2
b) 3
c) 4
d) 5
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5. A curved beam has neutral axis is curved while loaded and straight when unloaded.
a) True
b) False
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6. The bending stress in a straight beam varies linearly with the distance from neural axis like that in a curved beam.
a) True
b) False
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7. If for a curved beam of trapezoidal cross section, radius of neutral axis is 89.1816mm and radius of centroidal axis is 100mm, then find the bending stress at inner fibre whose radius is 50mm. Area of cross section of beam is 7200mm² and the beam is loaded with 100kN of load.
a) 97.3
b) 95.8
c) 100.6
d) None of the mentioned
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8. A curved beam with eccentricity 0.02D is loaded with 1kN.Centroidal radius=4D and inner and outer radii are 3.5D and 4.5D respectively. Area of cross section is 0.8D². Find the dimension D if allowable stress is 110N/mm².Considering only bending stress.
a) 14.80mm
b) 13.95mm
c) 16.5mm
d) 17.2mm
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9. A curved beam with eccentricity 0.02D is loaded with 1kN.Centroidal radius=4D and inner and outer radii are 3.5D and 4.5D respectively. Area of cross section is 0.8D². Find the dimension D if allowable stress is 110N/mm² and considering only direct tensile stress.
a) 4.7mm
b) 6.8mm
c) 13.95mm
d) 3.4mm
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10. A curved beam with eccentricity 0.02D is loaded with 1kN.Centroidal radius=4D and inner and outer radii are 3.5D and 4.5D respectively. Area of cross section is 0.8D². Find the dimension D if allowable stress is 110N/mm² and considering combined effect of direct stress and bending stress.
a) 15.8mm
b) 14.35mm
c) 17.9mm
d) 18.1mm
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11. If a hollow steel tube is heated from a temperature of 25’C to 250’C then fid the expansion of tube if area of the cross section is 300mm²,length of tube=200mm and coefficient of thermal expansion is 10.8 x 10⁻⁶ per ⁰C.
a) 1.22mm
b) 0.486mm
c) 0.878mm
d) 1.52mm
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12. All type of stresses vanishes after as soon as the applied load is removed.
a) True
b) False
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13. Residual stresses are always added in the load stresses and hence are always harmful.
a) True
b) False
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Sanfoundry Global Education & Learning Series – Machine Design.
To practice all areas of Machine Design, here is complete set of 1000+ Multiple Choice Questions and Answers.

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