Aircraft Design Questions and Answers – Structural-Analysis Fundamentals

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This set of Aircraft Design Multiple Choice Questions & Answers (MCQs) focuses on “Structural-Analysis Fundamentals”.

1. When we step on an upright soda can, it would fail due to __________
a) crippling
b) bending
c) torsion
d) shearing
View Answer

Answer: a
Explanation: When we step on an upright soda can, it would fail due to crippling. Here, walls of cross section will collapse without warning and the ability to carry load will become virtually zero. This can be viewed as the short Column with very thin walls.
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2. A rectangular section has b of 2m and h of 5m. Find centroid coordinates.
a) (1, 2.5)
b) (3, 0)
c) (4, 2)
d) (2, 4.8)
View Answer

Answer: a
Explanation: For rectangle, centroid coordinates = (b/2, h/2)
= (2/2, 5/2) = (1, 2.5).

3. Find the radius of gyration if, moment of inertia I is 160 unit and 10 unit as area.
a) 4 unit
b) 5 unit
c) 2.3 unit
d) 5.6 unit
View Answer

Answer: a
Explanation: Radius of gyration = \(\sqrt{\frac{Moment \,of\, inertia}{Area}}\)
= \(\sqrt{\frac{160}{10}}\) = 4 unit.

4. Which of the following is correct?
a) Radius of gyration K = (I/A)0.5
b) Radius of gyration K = (I/A)0.8
c) Radius of gyration K = (I/A)*0.2
d) Radius of gyration K = (I/A)*0.8
View Answer

Answer: a
Explanation: Above relationship is used to correlate radius of gyration K with moment of inertia I and cross section area A. Correct relationship is given by, radius of gyration K=(I/A)0.5 where, I = moment of inertia and A is the cross section area.

5. The highest compression load which will not cause the elastic column buckling is called _________
a) euler load
b) bernoulli’s theorem
c) newtonian fluid
d) divergence
View Answer

Answer: a
Explanation: Euler load is defined as the highest compression load which will not cause the elastic column buckling. Euler load is also termed as critical load. Bernoulli’s theorem is used for fluids. Newtonian fluid are those fluids which follow the Newton’s law of viscosity.
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6. How do you define slenderness ratio?
a) Ratio of column’s effective length to c/s radius of gyration
b) Ratio of slender body width to the bluff body height
c) Ratio of lift to drag
d) Ratio of Thrust to weight
View Answer

Answer: a
Explanation: The ratio of column’s effective length to c/s radius of gyration can be termed as slenderness ratio. The effective length of the column is determined based on the end constraints such as pinned joints, fixed ends etc.

7. Column is supported by pin at both the ends and has length of 10 unit. If radius of gyration is 3.16 unit then find slenderness ratio.
a) 3.16
b) 2.13
c) 5.67
d) 0.56
View Answer

Answer: a
Explanation: Given, column is supported by pin at both the end.
Now, slenderness ratio = effective length/ radius of gyration = 10/3.16 = 3.16.

8. Column has length of 1.2 m and radius of gyration as 1.5m. Determine slenderness ratio. Consider column is fixed at one end free at other end.
a) 1.6
b) 7.8
c) 98
d) 12.45
View Answer

Answer: a
Explanation: For, given column which is fixed at one end and free at other effective length L = 2*1.2m = 2.4m.
Now, slenderness ratio = effective length / radius of gyration = 2.4/1.5 = 1.6.

9. If a column has slenderness ratio of 2.2 and 1.8 as the radius of gyration. Determine effective length of the column.
a) 3.96
b) 8.98
c) 4.5
d) 1.09
View Answer

Answer: a
Explanation: Effective length = slenderness ratio*radius of gyration = 2.2*1.8 = 3.96.
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10. Determine the actual length of the column which has slenderness ratio of 2.9 and radius of gyration as 1.6. Consider column is fixed at both ends.
a) 9.28
b) 0.0045
c) 2.3674
d) 4.862
View Answer

Answer: a
Explanation: Given, column is fixed at both ends.
Actual length = slenderness ratio*radius of gyration/0.5 = 2.9*1.6/0.5 = 9.28.

11. A column has effective length as 20unit. Determine Euler load of EI = 1000 unit.
a) 24.67 unit
b) 10 unit
c) 40 unit
d) 50.99 unit
View Answer

Answer: a
Explanation: Euler load = \(\frac{\pi^2 EI}{(Effective \,length)^2}\)
= \(\frac{\pi^2*1000}{20^2} \) = 24.67 unit.

12. Stress and pressure are same.
a) True
b) False
View Answer

Answer: b
Explanation: Stress and pressure are two different properties. Stress is produced due to internal forces. Pressure is result of external force. Stress is defined as internal resistive force per unit cross section area. Unit of pressure and stress will be the same but not their physical explanation.

Sanfoundry Global Education & Learning Series – Aircraft Design.

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To practice all areas of Aircraft Design, here is complete set of 1000+ Multiple Choice Questions and Answers.

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Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He is Linux Kernel Developer & SAN Architect and is passionate about competency developments in these areas. He lives in Bangalore and delivers focused training sessions to IT professionals in Linux Kernel, Linux Debugging, Linux Device Drivers, Linux Networking, Linux Storage, Advanced C Programming, SAN Storage Technologies, SCSI Internals & Storage Protocols such as iSCSI & Fiber Channel. Stay connected with him @ LinkedIn