R.SAMY RAMASAMY
DEPARTMENT OF AERONAUTICAL ENGG
NEHRU INSTITUTE OF TECHNOLOGY, COIMBATORE
QUESTION BANK
AE 1253-AIRCRAFT STRUCTURES-I
PART-A
1. In unsymmetrical bending, the neutral axis passes thro
the centriod of the crosssection. (True/False).
2. A rectangular cross-section is subjected to a skew load.
Mark the neutral axis and
sketch the bending stress distribution.
3. When does unsymmetrical bending takes place.
4. A beam bends about its neutral axis for both symmetrical
and unsymmetrical
bending. (True/False).
5. Explain unsymmetrical bending with examples.
6. Define neutral axis and give expression to determine it.
7. Define principle axis of a section and give an expression
to determine it.
8. Draw bending stress variation across the depth for (a)
Rectangular section (b) Isection.
9. Distinguish between symmetric and unsymmetric bending.
10. What do you understand by unsymmetrical bending? Explain
a method to find the
stress in an unsymmetrical bending
11. Explain the Euler-Bernoulli hypothesis in bending of
beams.
12. Bending of a symmetric section subjected to a skew load
will be
(symmetric/Unsymmetric).Explain.
13. Shear flow can be defined for both thin and thick walled
section (true/false)
14. Sketch the shear flow distribution when a thin walled
L-section is subjected to a
vertical load.
15. Define shear center and elastic axis.
16. Define shear flow .How the shear stress is obtained from
the shear flow?
17. Indicate the shear center for channel section and angle
section.
18. Draw shear flow diagram for I section and Channel
section.
19. What is mean by distribution factor?
20. Define propped cantilever beam.
21. Write the expression for strain energy due to bending
and torsion.
22. Define proof resilience and modulus of resilience.
23. Define stiffness factor and moment distribution factor
in moment distribution
method.
24. Write down the Clapeyron’s three moment theorem in
general form.
25. State Castigliano’s theorems.
26. What is unit load method?
27. What is meant by order of indeterminacy? Explain with
example.
28. Define distribution factor in moment distribution
method. 29. Write down the expression for strain energy stored in a shaft of
length L
subjected to torque T and explain the terms.
30. State Maxwell’s reciprocal theorem.
31. What is linearly elastic structure?
32. Define indeterminate structure.
33. State Castigliano’s theorem.
34. State Maxwell’s reciprocal theorem.
35. Draw deflection curve for a simply supported beams
subjected to a
(a) UDL over its entire length and
(b) Moment at the center.
36. Write the Clapeyron’s three moment equation in general
form and explain the
terms.
37. Define Castigliano’s theorems.
38. Calculate the strain energy stored in a simply supported
beam of length L,
subjected to mid - point load P.
PART-B
1. Determine the normal stress at location A and G(refer
fig.1)for the following
cases of loading:
(i) Vx=1.2 kN acting through shear center.
(ii) Vy=1.2 kN acting through shear center.
Vx and Vy are
applied0.8 m away from the indicated cross-section.
2. (i)Derive and obtain an expression for the bending stress
in an unsymmetrical
section subjected to bending, using the generalized ‘k’
method (10)
(ii) Explain the neutral axis method of bending stress
determination mhen an
arbitrary section is subjected to bending moments Mx and My.
(6)
3. The section shown in fig.2 is subjected to bending moment
Mx=30kNm.determine the bending stress at the corner points
A, B, C and D.
4. A Z- section with 12 cm x 3 cm flanges and 20 cm x 3 cm
web is subjected to
Mx=10 kN-m and My=10 kN-m . Determine the maximum bending
stress.
5. A box beam with 50 cm length is subjected to loads Px=8kN
and Py=25kN as
shown in fig.3. The stringer area is 3 cm2
each. Find the
maximum bending
stress.
6. obtain the bending stress values at the points A,B,C and
D for the section
shown in fig.4.Compute the stresses using moment values with
respect to x
and y axis and the principle axis. 7. Compute the load on
the lumped flanges due to bending of the section shown
in fig.5.Assume the web do not take part in bending. Compute
the loads using
moment values with respect to x and y axis and principle
axis.
8. A beam section shown in fig.6.has four stringers. Area of
the stringers A, B, C
and D are 6.25, 3.125, 4.5 and 6sq.cm respectively. Find the
stresses in all the
four stringers of the section due to Mx=50kNm and My=-20kNm
where x and
y are the centriodal axes. Assume that webs and walls are
ineffective in
bending.
9. Refer fig.7.The section is subjected to an 8 kNm bending
moment in the x-z
plane and a 10 kNm bending in the y-z plane. Determine the
bending stresses
in all the corner points, indicating whether they are
tensile or compressive.
10. Determine the bending stresses in the stringer of the
section shown in fig.8
.E1= 70GPa , E2=210GPa and E3=100GPa.stringer areas are 2
cm2
11. A C-section beam of length 50 cm is subjected to loads
Px=100N .the Csection dimensions are (i) Flanges- 25 cm x3 cm (ii)web 30cm x
3cm. 1. Derive and obtain an expression for shear flow due to bending in the
case of an
arbitrary thin walled open section subjected to bending. How
to modify the results
you obtained for the case of closed section.
2. Plot the shear flow and locate the shear center for the
section shown in fig.9.
3. Plot the shear flow and locate the shear center for the
section shown in fig.10.
4. Find the shear flow for the section shown in fig.11.The
Area of the each stringer
=6 cm2
.the loads are Sx=10kN and Sy=50kN through the shear center
.Also find
the Shear center
5. Find the shear center of the section shown in fig.12.Area
a=b=4 cm2 and c=d=2
cm
2
6. Find the shear flow distribution and locate the shear
center for the section shown
in fig.13.Each of the stringers has an area of 4 cm2
and the section
subjected to
vertical shear of 50 kN.
7. Find the shear flow distribution in a thin walled
Z-section, whose thickness is‘t’,
height’h’. Flange width ‘h/2’ and subjected to vertical
shear load through shear
center.
8. (i) Show that the sum of the moment of inertia about any
two orthogonal axes is
invariant with respect to any other two orthogonal axes. (6)
(ii)Obtain the shear flow distribution and shear center
location for the section in
fig.14.When it is subjected to a shear load of 5 kN. (10)
9. Determine the shear center location for the section shown
in fig.15. All the webs
are ineffective in bending.
10. Locate the shear center for the section shown in
fog.16.Plot the shear stress
distribution when a vertical shear load of 1.2kNacts through
the shear center.
