DOM Manual ACT-Cycle-1 n

7/25/2019 DOM Manual ACT-Cycle-1 n

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MECHANICAL DYNAMICS LAB

1

Name :

Register No :

Sem./Year :

Class :

Course Teacher Head Of Department


2/19

2


!ST O" #$%#R!NTS

#'p.No.

Title of #'periment Staff Sig.

( Determination of natural fre)uenc* of longitudinal+i,ration of the spring mass s*stem.

-a Determine the characteristics of att go+ernor using

uni+ersal go+ernor setup.-, Determine the characteristics of porter go+ernor usinguni+ersal go+ernor setup.

/ Torsional +i,ration of to rotor s*stem.

0 Determination of hirling speed of shafts.

1 Determination of moment of inertia of inertia of fl*heeland connecting rod.


3/19

3


Determination of natural fre)uenc* of longitudinal +i,ration of thespring mass s*stem

#'p.No :( Date :

2im :To determine time period and natural fre)uenc* of longitudinal +i,ration of thespring

mass s*stem

2pparatus Re)uired :(3 Helicalspring-3 %latform3 4eights03 &easuring scale13 Stop atch

Descriptionof the setup:!t consists of an to open coil helical spring of hich one end is fi'ed to the scre rod

and a platform to the other end. This platform is used to add eights and a loc5 nut is alsopro+ided to clamp the eights added.

%rocedure:(3 "i' one end of the helical spring to the upper scre rod.-3 2ttach the other end to the platform and add some eight.3 Note don the deflection.03 Stretch the spring through some distance and release.13 O,ser+e the time ta5en for n 6 -7 oscillations.83 Repeat the steps from - to 1 for other 5non eights.

"ormulae:

(. Stiffness of the spring9 e'p 6 oad / deflection 6 4 / $ 9 N/m

-. #'perimental time period of +i,ration9 T e'p 6tm / n 9 sec4here9 tm6 mean time ta5en for n oscillations

n 6 num,er of oscillations 6 -7

. #'perimental fre)uenc* of +i,ration9 " e'p 6( / T e'p 9 H;

0. Theoritical fre)uenc* of +i,ration9 T theo 6 ?e'pm/ 4@ 9 H;

Or6


4/19

S.Nooad added9

4Deflection9

$ < m 3

Stiffness9 e'p 6 4

/ $

< N / m 3

Time ta5en for n 6 -7oscillations

< sec 3

%eriodof

+i,ration

< sec 3

"re)uenc* of

+i,ration

< H; 3g N t( t- t t0 t1 tm T e'p " e'p

(

-

6 Theoretical stiffness64/ 9 N/m6theoretical deflection 9m

804 n/c4here9 R6inner radius of spring9 m

O,ser+ation:

< 3initial length of the spring6 9m

< 3 length of the spring after load added6 9m

Deflection:

$6< 3 9 m

Ta,ulation:

e'pm

&odel calculation: Reading No. :


5/19

Result:Thus the natural fre)uenc* of longitudinal +i,ration of spring mass s*stem is founde'perimentall* and compared ith theoretical fre)uenc*.


6/19


6

Determinethe characteristics of att go+ernor using uni+ersalgo+ernor setup

#'p. No. : -a Date :

2im : To stud* the characteristics of att go+ernor and to dra the +arious characteristicscur+es.2pparatus Re)uired:

(. ni+ersal go+ernor-. Tachometer. Spanner

Descriptionof the setup:The dri+e unit consists of a DC electric motor connected through ,elt and pulle*

arrangement. &otor and test setup are mounted on a &.S. fa,ricated frame. The go+ernor spindleis dri+en ,* motor through E ,elt and is supported in a ,all ,earing.

The optional go+ernor mechanisms can ,e mounted on spindle. Speed is controlled ,* theelectronic control unit. 2 tachometer is used to determine the speed. 2 graduated scale is fi'ed tothe slee+e and guided in +ertical direction. Slee+e displacement is to ,e noted on the scalepro+ided.

The center slee+e of the att go+ernors incorporates no eight. DC motor ith dri+e:F H% motor and +oltage regulator control for speed +ariation. Separate lin5ages for go+ernorarrangements


7/19

2ngular+elocit* 9 6- N/87 9rad/sec

O,ser+ation:

is the initial length of the go+ernor 6 9m

is the length of the lin5 6 L9m

&ass of the eight ,all 6 95g

Ta,ulation:

Sl.No.

Mo+ernor

Speed


8/19

Result:Thus the characteristics of att go+ernor is studied and graphs are plotted.


9/19


9

Determinethe characteristics ofporter go+ernor using uni+ersalgo+ernor setup

#'p. No.:-, Date :

2im : To stud* the characteristics of porter go+ernor and to dra the +ariouscharacteristics cur+es.

2pparatus Re)uired:(. ni+ersal go+ernor-. Tachometer. Central load0. Spanner

Descriptionof the setup:

The dri+e unit consists of a DC electric motor connected through ,elt and pulle*arrangement. &otor and test setup are mounted on a &.S. fa,ricated frame. The go+ernor spindleis dri+en ,* motor through E ,elt and is supported in a ,all ,earing.

The optional go+ernor mechanisms can ,e mounted on spindle. Speed is controlled ,* theelectronic control unit. 2 tachometer is used to determine the speed. 2 graduated scale is fi'ed tothe slee+e and guided in +ertical direction. Slee+e displacement is to ,e noted on the scalepro+ided.

The centre slee+e of the %orter and %roell go+ernors incorporates a eight slee+e tohich eights ma* ,e added. DC motor ith dri+e: F H% motor and DC dri+e controlfor speed +ariation. Separate lin5ages for go+ernor arrangements


10/19

1


Ta,ulation:

Sl.No.

Mo+ernorSpeed


11/19

1


Torsional +i,ration of to rotor s*stem#'p.No : Date :

2im :To determine the time period and fre)uenc* of torsional +i,ration of the to rotor s*stem

e'perimentall* and compare it ith the theoretical +alues.

2pparatus Re)uired :i. #'perimental Shaft9 Spanner

ii. Chuc5 5e*iii. &easuring tapei+. Stop atch+. 4eights and

+i. Crossarms

Descriptionof the setup:

To discs ha+ing different mass moment of inertia are clamped one at each endof shaft ,* means of collet. &ass moment of inertia of an* disc can ,e changed ,* attaching thecross le+er ith eights. Goth discs are free to oscillate in the ,all ,earings. This pro+idesnegligi,le damping during e'periment.

%rocedure:i3 "i' the discs 2 and G to the shaft and fit the shaft in ,earing.ii3 Deflect the discs 2 and G in opposite directions ,* hand and release.iii3 Note don the time re)uired for n 6 oscillations.i+3 "it the cross arm to the disc 2 and attach e)ual masses to the ends of cross arm and again

note don time.

+3 Repeat the a,o+e procedure ith different e)ual masses attached to the ends of cross arm."ormulae:

( .#'perimental %eriod of Ei,ration Te'p6 /n sec.

here96mass time ta5en for n oscillations

n6num,er of oscillations

-. Theoretical %eriod of Ei,ration Ttheo 6 - = >!2 ' /M Q

here9mass moment of inertia 6 &2


12/19

S.No. &ass


13/19

&odel calculation: Reading No. :

Result:Thus the undamped fre)uenc* of torsional +i,ration ofto rotor s*stem is founde'perimentall* and compared ith theoretical fre)uenc*.


14/19


1

Determination of hirling speed of shafts

#'p.No :0 Date :

2im:

To determine the hirling speed for +arious diameter shafts e'perimentall* and compareit ith the theoretical +alues.

2pparatus Re)uired:(3Shaft nos. -3Digital tachometer3Chuc5 5e* 032C +oltage regulator

Descriptionof the setup:The apparatus is used to stud* the hirling phenomenon of shafts. This consists of a

frame in hich the dri+ing motor and fi'ing ,loc5s are fi'ed. 2 special design is pro+ided toclear out the effects of ,earings of motor spindle from those of testing shafts.

%rocedure:(3 The shaft is to ,e mounted ith the end condition as simpl* supported.-3 The speed of rotation of the shaft is graduall* increased.3 4hen the shaft +i,rates +iolent in fundamental mode < (st mode 39 the speed is noted don.03 The a,o+e procedure is repeated for the remaining shafts.

"ormulae:(. mass9 m 6 ' + 9 5g

p 6 Densit* of material 6 B7779 5g/m

+6 Eolume 6 =/0 ' d- ' l 9 m

-.Theoretical fre)uenc* of trans+erse +i,ration

"6 C

4here# 6 Youngs modulus!6 second moment of area of shaft46 eight per unit length of shaftg 6acceleration due to gra+it*C6 constant dependent upon the end conditions.6.18


15/19

Sl.No

Diameter ofthe shaft d


16/19

&odelcalculation : ReadingNo:

Result:Thus the hirling speeds of different si;ed shafts found e'perimentall* and comparedith theoretical +alues.


17/19


1

Determination of moment of inertia of inertia of fl*heel andconnecting rod

#'p.No :1 Date :

2im:

To find the mass moment of inertia of the Connecting rod ,* using oscillation method.

2pparatus Re)uired:

Gigger Connecting Rod Smaller Connecting Rod Stop atch

%rocedure: &easure the center distance of the connecting rod and also measure the inner

diameter of ,oth ends. &easure the eight of the connecting rod 2ttach the smaller ends of the connecting rod to shaft Mi+e the oscillation to connecting rod &easure the time ta5en for oscillation to calculate the time period. Remo+e the connecting rod from the shaft and again attach the ,igger rod to shaft 2gain measure the time ta5en for oscillation and calculate the time period


18/19

1


O,ser+ation:&ass of connecting rod

arger6 5gSmaller6 g

Center distance ,eteen holesGigger end6 mSmaller end6 m

Ta,ulation:

S.No.T*pes of

connectingrod

%ositionNo of

Oscillation

Time ta5en forn61oscillation


19/19

1


Result: Thus the mass moment of inertia of the gi+en to connecting rod as found ,*oscillation method.

DOM Manual ACT-Cycle-1 n

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