Sm 4 Experiments

8/12/2019 Sm 4 Experiments

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loading will eventually cause nickformation and rupture.

Usually a tension testis conducted at room temperature and the tensile load is

applied slowly. During this test either round of flat specimens may be used. The round

specimens may have smooth, shouldered or threaded ends. The load on the specimen is

applied mechanically or hydraulically depending on the type of testing machine.

FORMULA USED:

1. Original area of the rod !o" # $.1%&%" ' do"(

mm2

(. )eck area of the rod !)" # $.1%&%" ' d)"(

mm2

*here,

do#original area of cross section in mmd)

#diameter of the rod at the neck in mm

3. +ercentage reduction in area #

*here,

!o#original cross sectional area of the rod in

mm!)#)eck area of the rod in mm

4. +ercentage of longation #

*here,

-o#inal gauge length of the rod in mm

-o#Original gauge length of the rod in mm

/. 0ield stress # )&mm

(

. Ultimate stress # )&mm(

2. 3reaking stress # )&mm(

4. 0oungs modulus # )&mm(

*here,

+#-oad in )

-o#Original length in mm

!o#Original cross sectional area of the rod in

mm#5tension of the rod in mm

PROCEDURE:

1. 6easure the diameter of the rod using 7ernier caliper.

2. 6easure the original length of the rod.

3. 8elect the proper 9aw inserts and complete the upper and lower chuck assemblies.

4. !pply some graphite grease to the tapered surface of the grip surface for the

smooth motion.

5. Operate the upper cross head grip operation handle and grip fully the upper end of


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the test piece.

6. The left valve in UT6 is kept in fully closed position and the right valve in normal

open position.

7. Open the right valve and close it after the lower table is slightly lifted.


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8. !d9ust the load to :ero by using large push button This is necessary to remove the

dead weight of the lower table, upper cross head and other connecting parts of the

load".

9. Operate the lower grip operation handle and lift the lower cross head up and grip

fully the lower part of the specimen. Then lock the 9aws in this position by operating

the 9aw locking handle.

10. Turn the right control valve slowly to open position anticlockwise" until we get a

desired loadings rate.

11.!fter that we will find that the specimen is under load and then unclamp the locking

handle.

12. )ow the 9aws will not slide down due to their own weight. Then go on increasing the

load.13.!t a particular stage there will be a pause in the increase of load. The load at this

point is noted as yield point load.

14.!pply the load continuously, when the load reaches the ma5imum value. This is

noted as ultimate load.

15. )ote down the load when the test piece breaks, the load is said to be a breaking

load.

16. *hen the test piece is broken close the right control valve, take out the broken

pieces of the test piece. Then taper the left control valve to take the piston down.

GRAPH

Draw a graph between longations ';a5is" and load 0;a5is".

OBSERVATIONS

1. Original gauge length of the rod -o" # mm.

(. Original diameter of the rod do" # mm.

$. inal length of the rod # mm.

%. -oad at yield point # k).

/. Ultimate load # k).

. 3reaking load # k).

2. Diameter at the neck D)" # mm.

4.


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TABULATION:

LoadExtensomete ead!n"

Stess Sta!n #o$n"%s mod$&$sS'NO (mm)

(*N) (N+mm2) (No Un!t) , -.

/(N+mm

2)Le0t R!"1t Mean

RESULT:

1. inal length of the rod # ====== mm.

(. Diameter at the neck D)" #======mm.

$. +ercentage reduction in area #====== >

%. +ercentage of longation #====== >

/. 0ield stress # ====== )&mm(

. Ultimate stress # ====== )&mm(

2. 3reaking stress # ====== )&mm(

4. 0oung?s modulus # ====== ' 1@/)&mm

(


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IMPACT TEST CHARP#

AIM:

To determine the impact strength of the given material using Aharpy impact test.

APPARATUS RE3UIRED:

1. 7ernier caliper

2. 8cale

THEOR#:

!n impact test signifies toughness of material that is ability of material to absorb

energy during plastic deformation. 8tatic tension tests of unnotched specimens do notalways reveal the susceptibility of a metal to brittle fracture. This important factor is

determent by impact test. Toughness takes into account both the material. 8everal

engineering material have to with stand impact or suddenly loads while in service. Bmpact

strengths are generally lower as compared to strengths achieved under slowly applied

loads of all types of impact tests, the notched bar test are most e5tensively used.

Therefore, the impact test measures the energy necessary to fracture a standard notched

bar by applying an impulse load. The test measures the notch toughness of material under

shocking loading. 7alues obtained from these tests are not of much utility to design

problems directly and are highly arbitrary. 8till it is important to note that it provides a good

way of comparing toughness of various materials or toughness of same material under

different conditions. This test can also be used to assess the ductile brittle transition

temperature of the material occurring due to lowering of temperature.

FORMULA USED:

Bmpact strength # C&mm(

PROCEDURE:

1. aise the swinging pendulum weight and lock it.

2. elease the trigger and allow the pendulum to swing.

3. This actuates the pointer to move in the dial.

4. )ote down the frictional energy absorbed by the bearings.

5.aise the pendulum weight again and lock it in position.


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6. +lace the specimen in between the simple anvil support keeping the EUE notch in the

direction opposite to the striking edge of hammer arrangement.

7. elease the trigger and allow the pendulum to strike the specimen at its midpoint.

8. )ote down the energy spent in breaking or" bending the specimen.

9. Tabulate the observation.

OBSERVATION:

!rea of cross section of the given materialF

Ene"4 a5so5ed Ene"4 s6ent to Ene"4 Im6a7tMate!a& 5ea8 t1e a5so5ed 54

S'No 54 0o7e (A) Sten"t1Used s6e7!men (B) t1e s6e7!men

9 9+mm2

9 (AB) 9

Res$&t:

The impact strength for the given material is ========= C&mm(


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COMPRESSIONTEST ON OPEN COIL HELICAL SPRING

AIM:

To determine the stiffness of spring, modulus of rigidity of the spring wire andma5imum strain energy stored.

E3UIPMENTS RE3UIRED:

1. 8pring testing machine

2. ! open coil spring

3. 7ernier caliper

FORMULAE:

1. Deflection " # % *$n8ec G cos

( & ) H (8in

( &I )&mm(

d(

*here,

*#-oad applied in )ewton

#6ean radius of spring coil # D;d" & (

n# )o of Aoils

#Jeli5 angle of spring

)#6odulus of rigidity of spring 6aterial

#0oungs modulus of the spring material

2. Tan # pitch & (K

3. +itch # -;d" & n

*here,

d#Dia of spring wire in mm

-#-ength of spring in mm

)#no of turns in spring

4. 8tiffness of spring L"#w &

*here,

#Deflection of spring in mm

*#-oad applied in )ewton

/. 6a5imum energy stores # @./ 5 *ma55 ma5

*here,

*ma5#6a5imum load applied

6a5#6a5imum deflection


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PROCEDURE:

1. 3y using 7ernier caliper measure the diameter of the wire of the spring and also

the diameter of spring coil.

2. Aount the number of turns.

3. Bnsert the spring in the spring testing machine and load the spring by a suitable

weight and note the corresponding a5ial deflection in compression.

4. Bncrease the load and take the corresponding a5ial deflection readings.

5. +lot a curve between load and deflection. The shape of the curve gives the

stiffness of the spring

OBSERVATION:

Diameter of spring coil D" #

Diameter of spring wire d" #

)umber of turns in spring #

Ta5$&at!on: To detem!ne t1e &oad es$s de0&e7t!on (m!n -2 ead!n"s)

S7a&e ead!n"s De0&e7t!on !nR!"!d!t4

St!00nessS'No Load !n *"0 mod$&$s

!n mm mm !n N+mm!n N+mm2


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OBSERVATION:

To determine the wire diameter, and coil diameter of spring each $ readings"

-east count of 7ernier #

Ma!n S7a&e

Ven!e s7a&e VSR x LC !n

Tota& ead!n" ;

S'No Read!n" (MSR) !n MSR;(VSRxLC)ead!n" (VSR) mmmm !n mm

RESULT:

Under compression test on open coil helical spring

a. igidity 6odulus )" #

b. 8tiffness of spring L"#

c. 6a5imum energy stored #


10/19

DOUBLE SHEAR TEST ON GIVEN SPECIMEN

AIM:

To conduct shear test on given specimen under double shear.

E3UIPMENTS RE3UIRED:

1. UT6 with double shear chuck

2. 7ernier Aaliber

3. Test 8pecimen

DESCRIPTION:

Bn actual practice when a beam is loaded the shear force at a section always comes to

play along with bending moment. Bt has been observed that the effect of shearing stress as

compared to bending stress is Muite negligible. 3ut sometimes, the shearing stress at a

section assumes much importance in design calculations.

Universal testing machine is used for performing shear, compression and tension.

There are two types of UT6.

1. 8crew type

2. Jydraulic type.

Jydraulic machines are easier to operate. They have a testing unit and control unit connectedto each other with hydraulic pipes. Bt has a reservoir of oil, which is pumped into a cylinder,

which has a piston. 3y this arrangement, the piston is made to move up. 8ame oil is taken in

a tube to measure the pressure. This causes movement of the pointer, which gives reading for

the load applied.

DETAILS OF UTM:

AapacityF %@@ L).

ange F @ ; %@@ L).

PRECAUTION:

The inner diameter of the hole in the shear stress attachment is slightly greater than

that of the specimen.

PROCEDURE:

1. 6easure the diameter of the hole accurately.

2. Bnsert the specimen in position and grip one end of the attachment in the upper


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portion and the other end in the lower portion.


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3. 8witch on the main switch on the universal testing machine.

4. 3ring the drag indicator in contact with the main indicator.

5.


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IMPACT TEST I


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5. aise the pendulum weight again and lock it in position.

6. +lace the specimen in between the simple anvil support keeping the EUE notch in the

direction opposite to the striking edge of hammer arrangement.

7. elease the trigger and allow the pendulum to strike the specimen at its midpoint.

8. )ote down the energy spent in breaking or" bending the specimen.

9. Tabulate the observation.

OBSERVATION:

!rea of cross section of the given materialF

Ene"4 a5so5ed Ene"4 s6ent to Ene"4 Im6a7tMate!a& 5ea8 t1e a5so5ed 54

S'No 54 0o7e (A) Sten"t1Used s6e7!men (B) t1e s6e7!men

9 9+mm2

9 (AB) 9

RESULT:

The impact strength for the given material is ========= C&mm(


15/19

TORSION TEST ON MILD STEEL SPECIMEN

AIM:

To conduct the torsion test on the given specimen for the following

1. 6odulus of rigidity

2. 8hear stress

APPARATUS RE3UIRED:

1. 7ernier caliper

2. 8cale

FORMULA USED:

1. 6odulus of rigidity, A # )&mm(

*here,

#angle of degree

2. 8hear stress t" #T&- )&mm(

PROCEDURE:

1. 6easure the diameter and length of the given rod.

2. The rod is fi5ing in to the grip of machine.

3. 8et the pointer on the torMue measuring scale.

4. The handle of machine is rotate in one direction.

5. The torMue and angle of test are noted for five degree.

6. )ow the handle is rotated in reverse direction and rod is taken out

THEOR#:

! torsion test is Muite intruded in determining the values of modulus of rigidity of

metallic specimen the values of modulus of rigidity can be found out through observation

made during e5periment by using torsion eMuation

T&< # AN&-OBSERVATION:

D!amete o0 t1e S6e7!men ; mm

Ga$"e &en"t1 o0 t1e S6e7!men ; mm

TABULATION:

ANGLE OF T=!st !nTo>$e Mod$&$s o0 S1ea


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S'NO R!"!d!t4 StessT?IST Rod

NM NMM (N+mm2) (N+mm

2)

RESULT:

Thus the torsion test on given mild steel specimen is done and the values of

modulus of rigidity and shear stress are calculated


17/19

TENSION TEST ON CLOSED COIL HELICAL SPRING

AIM:

To determine the modulus of rigidity and stiffness of the given tension spring

specimen.

APPARATUS AND SPECIMEN RE3UIRED:

1. 8pring test machine

2. Tension spring specimen

3. 7ernier caliper

PROCEDURE:

1.6easure the outer diameter D" and diameter of the spring coil D" for the giventension spring.

2. Aount the number of turns i.e. coils n" of the given specimen.

3. it the specimen in the top of the hook of the spring testing machine.

4. !d9ust the wheel at the top of the machine so that the other end of the specimen can

be fitted to the bottom hook in the machine.

5. )ote down the initial reading from the scale in the machine.

6. !pply a load of (/kg and note down the scale reading. Bncrease the load at the rate of

(/kg up to a ma5imum of 1@@kg and note down the corresponding scale readings.

7. ind the actual deflection of the spring for each load by deducting the initial scale

reading from the corresponding scale reading.

8. Aalculate the modulus of rigidity for each load applied by using the following formulaF

6odulus of rigidity, ) # %+$n

d%

*here,

+ # -oad in )

# 6ean radius of the spring in mm D Pd &("

d # Diameter of the spring coil in mm

# Deflection of the spring in mm

D # Outer diameter of the spring in mm.

9. Determine the stiffness for each load applied by using the following formulaF

8tiffness, L # +&

10.ind the values of modulus of rigidity and spring constant of the given spring bytaking average values.


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OBSERVATION:


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1. 6aterial of the spring specimen #

(. Outer diameter of the spring. D # mm

$. Diameter of the spring coil, d # mm

%. )umber of coils & turns, n # )os.

/. Bnitial scale reading # cm # mm

A66&!ed Load !n S7a&e ead!n" !nA7t$a& Mod$&$s o0

St!00nessS'No

de0&e7t!on !"!d!t4

!n N+mm8" N 7m mm !n mm In N+mm2

!verage

Res$&t:

The modulus of rigidity of the given spring # ;;;;;;;;;;;;;;;;;;; )&mm(

The stiffness of the given spring # ;;;;;;;;;;;;;;;;;;; )&mm(

Documents

Sm 4 Experiments