# Aircraft Design MCQ – Structural-Analysis Fundamentals

1 - Question

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

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.

2 - Question

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

3 - Question

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
Explanation: Radius of gyration = MomentofinertiaArea−−−−−−−−−−−−√ = 16010−−−√ = 4 unit.

4 - Question

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
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 - Question

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

6 - Question

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
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 - Question

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
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 - Question

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
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 - Question

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
Explanation: Effective length = slenderness ratio*radius of gyration = 2.2*1.8 = 3.96.

10 - Question

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
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 - Question

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