a107412101-Vibrations and Structural Dynamics_2nd Mid

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Code No: A107412101 Set No. 1JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD

IV B.Tech. I Sem., II Mid-Term Examinations, November 2010VIBRATIONS AND STRUCTURAL DYNAMICS

Objective ExamName: ______________________________ Hall Ticket No.

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

I Choose the correct alternative:

1. The influence coefficient of cantilever beam at the free end subjected to point load is given be

[ ]

a) 3L3/EI b) L

3/3EI c) L

3/EI d) 2L

3/3EI

2. The influence coefficient of simply supported beam subjected to point load at the centre is given by

[ ]

a) L3/48EI b) 48L

3/3EI c) L

3/3EI d) 48L

3/EI

3. The influence coefficient of fixed beam subjected to point load at the centre is given by [ ]a) L

3/3EI b) L

3/48EI c) L

3/192EI d) 192L

3/EI

4. Stodola method is [ ]a) An exact method b) Approximate method c) Derived method d) Analytical method

5. When the running speed of the shaft is equal to the critical speed, the amplitude of vibrationbecomes [ ]

a) Finite b) Infinite c) Cannot be determined d) twice the amplitude at half the critical speed

6. If y is the static deflection of shaft, then the angular frequency of vibration is [ ]

a) root of g/y b) root of 2g/y c) root of y/g d) none

7. Whirling speed of the shaft is [ ]a) speed of the shaft below resonance condition b) speed of the shaft above resonance condition

c) speed of the shaft at resonance d) speed of the shaft at half the resonance speed

8. Dunkerleys method considers [ ]

a) Static deflections b) Dynamic deflections

c) both static and dynamic deflections d) neither static nor dynamic deflections

9. The accuracy of solution is good if the problem of dynamic vibrations is solved using [ ]

a) lumped mass modelb) consistent mass matrix methodc) either lumped mass model or mass matrix method

d) neither lumped mass model nor mass matrix method

10. The unit of influence coefficient is [ ]

a) N/m b) m/N c) n/m2

d) none

Cont2


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Code No: A107412101 :2: Set No. 1

II Fill in the blanks

11. Whirling speed of the shaft also called____________

12. The Dunkerleys formula is ______________

13. The Rayleighs formula for shaft subjected to point loads is ______________

14. Rayleighs formula for transverse vibrations of beam to determine the natural frequency is

____________

15. The governing equation for dynamic vibrations using FEM approach with damping is ___________

16. The total lumped mass matrix for dynamic vibrations using FEM approach is____________

17. A bar of length L is divided into two elements of equal lengths. If A is the area, E, Youngsmodulus, , the density, the total consistent mass matrix is given by_____________

18. Total stiffness matrix for a bar of dimensions and properties L, A, E and is ______________

19. The total lumped mass matrix for a bar of dimensions and properties L, A, E and is___________

20. The vibrations which die down in short duration of time are called___________

-oOo-


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1. Stodola method is [ ]

a) An exact method b) Approximate method c) Derived method d) Analytical method

2. When the running speed of the shaft is equal to the critical speed, the amplitude of vibration

becomes [ ]




4. Whirling speed of the shaft is [ ]

a) speed of the shaft below resonance condition b) speed of the shaft above resonance conditionc) speed of the shaft at resonance d) speed of the shaft at half the resonance speed

5. Dunkerleys method considers [ ]a) Static deflections b) Dynamic deflections



a) lumped mass modelb) consistent mass matrix method

c) either lumped mass model or mass matrix methodd) neither lumped mass model nor mass matrix method

7. The unit of influence coefficient is [ ]a) N/m b) m/N c) n/m

2d) none

8. The influence coefficient of cantilever beam at the free end subjected to point load is given be[ ]

a) 3L3/EI b) L

3/3EI c) L

3/EI d) 2L

3/3EI

9. The influence coefficient of simply supported beam subjected to point load at the centre is given by[ ]

a) L3/48EI b) 48L

3/3EI c) L

3/3EI d) 48L

3/EI

10. The influence coefficient of fixed beam subjected to point load at the centre is given by [ ]

a) L3/3EI b) L

3/48EI c) L

3/192EI d) 192L

3/EI

Cont2


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Code No: A107412101 :2: Set No. 2



____________



14. A bar of length L is divided into two elements of equal lengths. If A is the area, E, Youngsmodulus, , the density, the total consistent mass matrix is given by_____________







-oOo-


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2. Whirling speed of the shaft is [ ]

a) speed of the shaft below resonance condition b) speed of the shaft above resonance condition



a) Static deflections b) Dynamic deflectionsc) both static and dynamic deflections d) neither static nor dynamic deflections

4. The accuracy of solution is good if the problem of dynamic vibrations is solved using [ ]a) lumped mass model

b) consistent mass matrix method

c) either lumped mass model or mass matrix methodd) neither lumped mass model nor mass matrix method

5. The unit of influence coefficient is [ ]a) N/m b) m/N c) n/m

2d) none


[ ]a) 3L

3/EI b) L

3/3EI c) L

3/EI d) 2L

3/3EI


a) L3/48EI b) 48L

3/3EI c) L

3/3EI d) 48L

3/EI

8. The influence coefficient of fixed beam subjected to point load at the centre is given by [ ]

a) L3/3EI b) L

3/48EI c) L

3/192EI d) 192L

3/EI




Cont2


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Code No: A107412101 :2: Set No. 3



12. A bar of length L is divided into two elements of equal lengths. If A is the area, E, Youngs

modulus, , the density, the total consistent mass matrix is given by_____________








____________


-oOo-


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a) Static deflections b) Dynamic deflections



a) lumped mass model

b) consistent mass matrix methodc) either lumped mass model or mass matrix method

d) neither lumped mass model nor mass matrix method

3. The unit of influence coefficient is [ ]

a) N/m b) m/N c) n/m2

d) none


[ ]a) 3L

3/EI b) L

3/3EI c) L

3/EI d) 2L

3/3EI


a) L3/48EI b) 48L3/3EI c) L3/3EI d) 48L3/EI

6. The influence coefficient of fixed beam subjected to point load at the centre is given by [ ]a) L

3/3EI b) L

3/48EI c) L

3/192EI d) 192L

3/EI




9. If y is the static deflection of shaft, then the angular frequency of vibration is [ ]a) root of g/y b) root of 2g/y c) root of y/g d) none

10. Whirling speed of the shaft is [ ]a) speed of the shaft below resonance condition b) speed of the shaft above resonance condition


Cont2


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Code No: A107412101 :2: Set No. 4








17. Rayleighs formula for transverse vibrations of beam to determine the natural frequency is____________



20. A bar of length L is divided into two elements of equal lengths. If A is the area, E, Youngs

modulus, , the density, the total consistent mass matrix is given by_____________

-oOo-

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a107412101-Vibrations and Structural Dynamics_2nd Mid