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Code No: 55067 Set No. 1

JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABADIII B.Tech. I Sem., I Mid-Term Examinations, Aug/Sept 2013

AREOSPACE VEHICLE STRUCTURES-IIObjective Exam

Name: ______________________________ Hall Ticket No.

Answer All Questions. All Questions Carry Equal Marks.Time: 20 Min. Marks: 10.

I Choose the correct alternative:

1. The operator2 2

2 2x y

+

is the well known __________ operation in two dimension. [ ]

A) Integral B) Laplace C) differential D) none of this

2. W=1 1 mnm n

m x n yA Sin Sin

a b

= = Where mnA Is [ ]A) Coefficient B) Known Coefficient C) Unknown Coefficient D) None

3. Direct and shear forces per unit length produced by in-plane load are given by [ ]notation

A) , ,x y xyN N N B) , ,x y xyM M M C) , ,x y xyq q q D) None

4. The transition from one buckling mode to next is found by equation value of k for the [ ]

_____________ curves.

A) M-1 & M+1 B) M & M+1 C) M & N D) M+1 &

5. Values of local buckling stress have been determined by BOUGHAN for idealized for [ ]

__________ stiffened panelsA) T & I B) Z & L C) Z &T D) None

6. The plane which neither stretches nor compresses ____________. [ ]A) Neutral Plane B) Horizontal Plane C) Vertical Plane D) None

7. According to perpendicular axes theory a polar second moment of area = [ ]

A) soR PR

A=

B) xx yyI I C) xx yyI I D) xx yyI I+

8. Wrapping of the cross section is produced by combination of ______caused by _____ [ ]

A) Roll, Slide B) Displacement , Tensile

C) Tensile, Compression D) Displacement , Twisting

9. Condition for zero wrapping at a section is [ ]

A)1

2

PR

Gt A= B)

1

2

PR

Gt A= C)

1

2

PR

Gt A< D)

1

2

PR

Gt A>

10. ________ is the area swept out by a generator .rotating about the center of twist from the point of

zero wrapping. [ ]

A) 12

soR PR

A=

B) soR PR

A=

s C) 12

soR PR

A=

D) 14

soR PR

A=

Cont2

A

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2/20

Code No: 55067 :2: Set No. 1

II Fill in the blanks:

11. A surface possessing the curvature of opposite sign is known as _____________.

12. If Mx=My=M then the deformed shape of the plate is spherical and of curvature is ________.

13. Plate buckling coefficient is given by minimum value of k=____________.

14. Critical stress with various edge support and loaded by constant in-plane direct force is given by________

15. The flangs &webs of thin walled columns having slenderness ratio less than 20 under a axial compressive

load will undergo___________________.

16. If a beam undergoes deformation under a applied external moment such that the upper surface is concave

and lower is convex, then it is called as ________________ bending moment.

17. _____________and ____________ section beams are double symmetry.

18. In equation 1/R=M/EI, EI is known as_____________.

19. The theory of the torsion of closed section beams is known as ____________ theory.

20. In determining the direct stress distribution for a unsymmetric bending of then walled beam under;pure

bending moment,the normal force acting is usually taken as__________________.

-o0o-




3/20


AREOSPACE VEHICLE STRUCTURES-II

KEYS


1. B

2. C

3. A

4. B

5. C

6. A

7. D

8. D

9. B

10. C


11. Anticlastic surface

12.( )

11

M

D v=

13.

2mb a

Ka mb

= +

14.

22

212(1 )CR

K E t

v b

=

15. Buckling

16. Sagging

17. Rectangular & I- section

18. EI=flexural rigidity

19. Bredt-batho

20. Zero

-oOo-

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4/20


JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABADIII B.Tech. I Sem., I Mid-Term Examinations, August 2012





1. The plane in which the direct stress in zero is called as [ ]

a) In-plane b) Neutral plane c) Top-line d) Bottom plane

2. The beam which is linearly elastic obeys _____________ law. [ ]

a) Elastic b) Hooks c) Bending d) Buckling

3. The product EI is known as [ ]

a) Modulus of rigidity b) Second moment of area c) Elastic bending d) Flexural rigidity

4. The second moment of area is given as [ ]

a) b) c) d)2A

y dA2

Ay dA

3

Ay dA

3

Ay dA

5. Bredt batho formulae is given as [ ]

a)1

2T A= q b)

1

2T A c) T = 2Aq d) T = -2Aqq=

6. The beam for which PRGT is constant [ ]a) Closed beam b) Open beam c) Neuber beam d) Tension field beam

7. If mid line of the beam is being wrapped then it is known as [ ]a) Primary wrapping b) secondary wrapping

c) common wrapping d) Neutral wrapping

8. Rate of twist is given as [ ]

a)d

G T b)d

T G c)dz

T G d)dz

G TJdz

= J

dz

= J

d= J

d=

9. Laplace operator in two dimensions is written as [ ]

a) ( )2z D

wq

= b) ( )2z q

wD

= c) ( )2z q

wD

= d) ( )2z D

wq

=

10.

__________________ stiffners are used to divide the skin in two narrow panels [ ]a) Lateral b) Inclined c) Narrow d) Longitudinal

Cont2

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5/20

Code No: 55067 :2: Set No. 1


11. The middle plane of the plane does not deform during bending and is therefore a __________ plane.

12. My=1

D1

y x

+ where D is known as _______________of the plate.

13. For principle moments Mt=_________________.

14. The total deflection W = _________________, if transverse and in-plane loads are acting on a plate.

15. For transverse loading potential energy V of the total load on plate is V = _________________.

16. Spars of aircraft wing structures are known as ________________.

17. The transition from one buckling mode to next, may be found by equating values of k, for___________

curves.

18. For combination of both primary and secondary modes, the range of is between _____ & ____.

19. The ultimate load is not reached until the stress in the plate exceeds ____________.

20. le= d for b > __________.

-o0o-

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6/20



KEYS


1. B

2. B

3. D

4. A

5. C

6. C

7. A

8. B

9. C

10. D


11. Neutral plane

12. Flexural rigidity

13. Zero

14. W = W0+ W1

15.0 0

a b

V wq d = x dy

16. Tension field beams

17. m and m+1

18. 20 and 80

19. Elastic limit

20. > 1.5d

-oOo-

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7/20

Code No: 55067 Set No. 1JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD

III B.Tech. I Sem., I Mid-Term Examinations, September 2011AEROSPACE STRUCTURES-II

Objective ExamName: ______________________________ Hall Ticket No.



1. In the simple beam theory, the direct strains below the neutral plane are [ ]

(a) z/x, =z/y (b) =z/x (c) =z/x (d) nonex= y y x

2. The deformed shape of the plate is spherical and of curvature is [ ]

(a) M=D(1+) (b) 1/ =M/D(1+) (c) 1/ =M (d) none

3. For a plate subjected to pure bending and twisting in which M ,M M are in Variable [ ]

(a) Through out the edge (b) through out the surface

X Y, XY

(c) through out the plate (d) none.

4. If the edge x=0 is built in or firmly clamped so that it can [ ]

(a) Neither rotates nor deflects (b) bending (c) shearing (d) none

5. For small deflections w/ x and (w/ x+ w/ x )x are small and the cosines of the angles are2 2

[ ](a) =0 (b) =1 (c) =2 (d) none.

6. The application of transverse and in plane loads will cause the plate to deflect a further amount

w so that the total deflection is then [ ]1 (a) w (b) w (c) w=w +w (d) none0 0 1

7. The potential energy v of the load N y, refer to the un deflected position of the plate as the

datum is then v = [ ]x X

x

(a) -N y (b) y (c) N (d) none.X X

8. For p


8/20

Code No: 55067 :2: Set No. 1

II Fill in the blanks

11. If the plate is subjected to a distributed transverse load, the deflection w infinite trigonometrical

equation is __________________.

12. If the equivalent length of the panel acting as a column is lethen the Euler critical stress

is__________.

13. In complete diagonal tension field beam may be analysed by ___________

14. The method of distributing the sheet areas into concentrated areas at the ends is_______________

15. Shear centre for the angle section lies at __________.

16. If the diameter of the fuselage increases ___________

17. The direct stresses on an element of area A at appoint (x,y) and a distance from the neutralaxis is_________

z

18. Bredt-Batho formula for torsion of Thinwalled closed section beam is ___________.

19. The second moment of area about an axis through o perpendicular to the plane of the section is

then___________

20. In thin walled sections shear stresses produced by____________

-oOo-

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9/20

Code No:55067 Set No. 1

AEROSPACE STRUCTURES-II

KEYS


1. A

2. B

3. C

4. A

5. B

6. C

7. A

8. B

9. C

10. A


11.

1 1

sin sinmnm n

m x n yw A

a b

= =

=

12. CR=2E/(le/r)

2

13. Semi elliptical theory

14. Structural idealization.

15. at the junction

16. torsional resistance increases.

17. z=EZ.

18. macauley

19. I0=IXX+IYY20. Shear loads

-oOo-

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10/20


JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABADIII B.Tech. I Sem., II Mid-Term Examinations, November 2013





1. After idealization of a fuselage in to boom and thin walled skin of thickness Dt , generally it is assumed

that booms area carries the following stress. [ ]

A) Direct stress B) Torsional stress C) Shear stress D) All the above

2. The position of the neutral axis is derived from the condition that the resultant load on the beam

cross-section is ______________. [ ]

A) Zero. B) One C) Two D) Both A & B

3. The phenomenon of load redistribution resulting from shear is known as _______________. [ ]A) Shear Strain B) C) D) Shear Force

4. The shear stress systems predicted by each portion of theory must be compatible atThe __________________________end. [ ]

A) Below B) Over C) Built-Out D) Built- In

5. Thezero warping axisproduce __________________due to twist, although axial constraint stresses due

shear [ ]

A) No Warping B) Max-Wraping C) Min-Wraping D) Partial Wraping

6. If the beam were of open cross-section the shear loads would be applied through its [ ]A) Leading Edge B) Shear Centre C) Strain D) Both A & B

7. If the beam were of open cross-section the shear loads would be applied through its shear centre, so tha

________of the beam occurred [ ]

A) Stress B) Bending C) Twisting D) Breaking

8. Wrapping in many aircraft, structural beams, such as wings, have stringers whose cross-sectional areas var

the _____________________direction. [ ]

A) Vertical B) Horizontal C) Z- Axis D) Span Wise

9. The determination of the ________________distribution in the skin produced by shear is basically the

analysis of an idealized single cell closed section beam. [ ]

A) B) Shear Stress C) D)Shear

10. A fuselage section is basically a _____________section beam. [ ]

A) B)Single Cell Closed C) D)

Cont2




11/20

Code No: 55067 :2: Set No. 1


11. The number and nature of simplifying assumptions determine the ____________________and the

_______________________of the analysis.

12. Replace the _________________ and _________________flanges by concentrations of area knownasbooms.

13. In any idealization, _________________conditions are require for different idealizations of the same

Structure.

14. The _______________axisproduce no warping due to twist, although axial constraint stresses due to she

15. In cases of doubly symmetrical beams do the ________________ and _______________axes coincide

_______________.

16. The calculation of shear stresses in beam ________________can be significantly affected by taper.

17. Beam tapered in two directions along its length and comprising an arrangement of ______________ and

______________________.

18. Aircraft fuselages consist, of thin sheets of material stiffened by large numbers of

_________________together with _________.________.

19. The distance between adjacent stringers is usually small so that the variation in _________________in the

connecting panel will be small.

20. The skin/stringer arrangement is idealized into one comprising ______________ and ______________.

-o0o-




12/20



KEYS


1. A

2. A

3. C

4. D

5. A

6. B

7. C

8. D

9. A

10. B


11. ACCURACY, DEGREE OF COMPLEXITY

12.

13.

14.

15.

16. WEBS

17. BOOMS AND SKIN.

18. LONGITUDINAL STRINGERS, TRANSVERSE FRAMES

19. SHEAR FLOW

20. BOOMS AND SKIN.

-oOo-




13/20


III B.Tech. I Sem., II Mid-Term Examinations, November 2012AREOSPACE VEHICLE STRUCTURES-II




1. We replace the stringers & spar flanges by concentrations of areas known as [ ]

a) booms b) points c) nodes d) none

2. If the skin is fully effective in carrying direct stress where tD= [ ]a) zero b) t c) 1 d) -1

3. Change in boom load over unit length of rth

boom Pr is [ ]

a) q1+ q2 b) q1- q2 c) q2- q1 d) none

4. Direct stress is zero for the fibers that do not change in length are called as [ ]a) zero fiber b) neutral fiber c) plane fiber d) linear fiber

5. Line of inter section of the neutral plane & any cross-section of the beam is termed as [ ]a) plane axis b) axis c) neutral axis d) linear axis

6. The term 2A

y dA is known as [ ]a) moment of area b) moment of inertia c) first moment of area d) second moment of area

7. The bending moment resultants Pz,1& Pz,2are parallel to _______ axis of the beam [ ]a) X b) Y c) Z d) neutral axis

8. For a beam in which the web is fully effective in resisting [ ]a) shear stresses b) bending c) strain d) direct stresses

9. Lift and drag loads induce shear flows in the skin panels, which are ______ between adjacent booms[ ]

a) maximum b) minimum c) zero d) constant

10. Bending moment at any section of a wing are usually produced by______ at other sectionsof the wing. [ ]

a) shear loads b) direct loads c) shear stress d) none

Cont2

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14/20

Code No: 55067 :2: Set No. 1


11. If all direct stresses are carried by booms, while the skin is effective only in __________

12. Shear loads produce _______________ due to bending in the booms.

13. Section properties Ixx, Iyy & Izz are calculated for the _________ carrying area only.

14. In symmetrical bending theory, the X axis becomes the ____________ when My = 0.

15. The neutral axis always passes through the _________ of area of a beams cross-section.

16. For a beam having either Cx or Cy as an axis of symmetry, Ixy =0. U = ____________.

17. Shear flows induce complementary shear flows in the panels in the _______________ of the beam.

18. In addition to ____________ the beam is subjected to bending moments Mx & My which produces

direct stresses in the booms & skin.

19. Wings and fuselage have openings in their surfaces to accommodate _________________.

20. Deflections of multi cell wings may be calculated by ______________ method.

-o0o-

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15/20



KEYS


1. A

2. B

3. C

4. B

5. C

6. D

7. C

8. D9. D

10. A


11. Shear

12. Direct stresses

13. Direct stress

14. Neutral axis

15. Centroid

16. U =y

yy

M

EI

17. Longitudinal direction

18. Shear loads

19. Under carriages,engine nacelles & weapons

20. Unit load

-oOo-

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16/20


III B.Tech. I Sem., II Mid-Term Examinations, November 2011AEROSPACE STRUCTURES-II




1. The basic function of an aircrafts structure are to transmit and resist the [ ]

(a) applied loads (b) variable loads (c) bending loads (d) None

2. Thin shells which rely entirely on their skins for their capacity to resist loads are Reffered to as

[ ]

(a) Semi-monocoque (b) mono-coque (c) circular-section (d) none

3. Stiffness problems may be conveniently grouped under the heading [ ]

(a) Elasticty (b) modulus of rigidity (c) Aero elasticity (d) none

4. The line of intersection of the neutral plane and any cross-section of the beam is known as[ ]

(a) Neutral axis (b) Horizontal axis (c) Vertical axis (d) None

5. The product of inertia is not zero for the following section [ ]

(a) Symmetric section on both axis (b) Symmetric section about one axis(c) Unsymmetric section about both axis (d) None

6. The best way of increasing the stiffness of the panel is [ ](a) Increasing the thickness of the panel (b)decreasing the stiffness of the panel

(c) providing stiffeners (d) None

7. The structural member which runs along the length of fuselage is [ ](a) bulk head (b) shear clip (c) longeron (d)aileron

8. The shape to the wing is due to [ ](a) bulk head (b) ribs (c) flaps (d) stringers

9. The diagonal tension field theory is given by [ ](a) Euler (b) Hook (c) Wanger (d) Rankine

10. Increasing the space between the bulkheads, the shear panel buckling resistance [ ](a) increases (b) decreases (c) uneffects (d) none

Cont.2

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17/20

Code No: 55067 :2: Set No. 1


11. The fuselage shell section has been idealized such that the fuselage skin is effective only in

______________

12. Wings and fuselages are usually tapered along their lengths for greater ______________

13. Wing ribs perform functions similar to those performed by ________________

14. A thin rectangular strip suffers warping across its thickness when subjected to ______________

15. The theory of the torsion of closed section beams is known as ________________

16. A section does not remain rectangular but distorts; the effect is known as ___________

17. If the shear force is 400 N over the length of the 200 mm stiffener, the shear flow is_____________

18. A bending moment M applied in any longitudinal plane parallel to the z-axis may be resolved intocomponents _______________

19. For a symmetric section about both axes, the shear centre lies at _________________

20. In many aircrafts, structural beams, such as wings, have stringers whose cross-sectional areas vary

in the ______________________ direction.

-oOo-

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18/20


AEROSPACE STRUCTURES-II

KEYS


1. A

2. B

3. C

4. A

5. C

6. C

7. C

8. B

9. C

10. B


11. Shear

12. Structural efficiency

13. Fuselage frames

14. Torsion.

15. Bredt-Batho theory

16. Anticlastic bending

17. 2 N/mm

18. Mxand My

19. geometric centre

20. spanwise direction

-oOo-

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19/20

Code No: 07A52103 Set No. 1

JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABADIII B.Tech. I Sem., II Mid-Term Examinations, November 2010

AEROSPACE VEHICLE STRUCTURES-IIObjective Exam




1. [ ]

2. Principal stresses can be represented graphically by [ ]

a) Rayleigh method b) Mohrs method c) Euler method d) Rankine method

3. A shaft subjected to torsion experiences a pure shear stress on the surface. The maximum

principal stress on the surface, at 450to the axis, is [ ]

a) cos 450 b) 2 cos 45

0 c) cos

245

0 d) 2 sin 45

cos 45

0

4. [ ]

5. [ ]

Cont..2

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20/20

Code No: 07A52103 :2: Set No.1

6. A square bar of side 4 cm and length 100 cm is subjected to an axial load P, the same bar is

then used as a cantilever beam and subjected to an end load P, the ratio of the strain energiesstored in the second case to that in the first case , is [ ]

a) 12 b) 400 c) 1000 d) 2500

7. Strain energy stored in an axial bar due to axial load P is [ ]a) P

2L/AE b) P

2L/2AE c) 2P

2L/AE d) P

2L/4AE

8. The maximum principal stress theory is given by [ ]

a) Vons mises b) St.venant c) Rankine d) Guest

9. Torsion of hollow thin walled closed cells is given by [ ]a) Euler theory b) Johnson theory c) Bredt-batho theory d) Timoshenko theory

10. Torsion of thin walled multicell closed hollow structure is [ ]a) Statically determinate problem b) Statically indeterminate problem

c) Both a and b d) none


11. Shear flow is defined as _____________

12. If q1and q2are the shear flows and A1and A2 are the mean areas of thin walled two cellclosed structure subjected to torque T, T is given by ____________

13. The strain energy stored in cantilever beam subjected to point load P is ______________

14. The total strain energy in the simple supported beam with point load at the centre is givenby _________________

15. When the Normal stress on the inclined plane is maximum, the shear stress becomes_____________________

16. The maximum strain energy theory is given by _________________.

17. If the mean area of a hollow tube is 100 mm2and subjected to torque of 2000 Nmm, the

shear flow in N/mm is _____________

18. If the working stress is 200 N/mm2

and yield stress is 400 N/mm2

, the Factor of safetyaccording to maximum principal stress theory is _________________

19. If U is the total strain energy due to point load P, the deflection under the load by

castiglino;s theorem is given by ____________

20. If M is the bending moment due to external load, m is the bending moment due top unit

load at that section, according to unit load method, the deflection under the load is given

by _____________________

O

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