lmmec220

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LABORATORY MANUAL

MEC220

SOLID MECHANICS LABORATORY

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TABLE OF CONTENTS

S.No. Title of theExperiment PageNo.

1. To perform tensile test on a specimen material

using universal testing machine (UTM)3-5

2. Verification of the bending equation and

determination of flexural rigidity and elastic

modulus for a given beam

6-8

3. To perform torsion test on a specimen and find

the modulus of rigidity of the material9-11

4. To determine the hardness of a specimen

material using Brinell's hardness test.12-13

5. To determine the hardness of a specimen

material using Rockwell hardness test14-15

6. To determine the stiffness of spring, modulus ofrigidity of the spring wire and the maximum

strain energy stored

16-18

7. To perform the compression test on a specimen

material and find the compression strength19-21

8. To determine the impact strength of a specimen

material using Charpy's test; To determine the

impact strength of a specimen material using

Izod test

22-24

9. To perform shear test on a specimen material

using universal testing machine25-26

10. To find the fatigue strength of a specimen

material by performing the fatigue test

27-29

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Experiment: 1

Experiment: To perform tensile test on a specimen material using universal testing machine

(UTM)

Equipment Required: Universal Testing Machine, Scale, Vernier calliper

Material Required: Specimen of MS & CI

Learning Objectives: Understanding of stress - strain diagrams, tensile strength of a

material, significance of Young's modulus

Outline of the Procedure: Measure the original length and diameter of the specimen. The

length may either be length of gauge section which is marked on the specimen with a preset

punch or the local length of the specimen. Insert the specimen into test machine. Begin the

load application and record load Vs elongation data. Measure elongation values with the help

of dividers and a ruler. Continue the test till fracture occurs. Measure the final length anddiameter of specimen.

Required Results:

Parameters:

A) Original dimensions:

Length= ----------------------

Diameter= ----------------------

Area= ----------------------

B) Final Dimensions:

Length= -----------------------

Diameter= -----------------------

Area= ------------------------

Average breaking Stress =

Ultimate Stress =

Average Percentage Elongation =

Relationships to be determined: Relationship between stress and strain

Graphs/Plots: Stress vs strain plot and identify yield point, ultimate tensile strength and E

and % elongation and % reduction in area.

Error Analysis:

Cautions: If the strain measuring device is an extensometer it should be removed before

necking begins. Measure deflection on scale carefully and accurately.

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Date of Performance Worksheet of the student Registration Number:

Aim: To perform tensile test on a specimen material using universal testing machine (UTM)

Observations:

S. No. Load(N) Original

Gauge length

Extension

(mm)

Stress

(N/mm2)

Strain

Calculations:

Graphs attached:

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Result and Discussion:

Error Analysis:

Learning Outcomes:

To be filled in by Faculty:

S.No

.

Parameter Marks obtained Max.

Marks

1 Understanding of the student about the

procedure/apparatus.

20

2 Observations and analysis including learning

outcomes

20

3 Completion* of experiment, Discipline and

Cleanliness

10

Signature of Faculty Total marks obtained

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Experiment: 2

Experiment: Verification of the bending equation and determination of flexural rigidity and

elastic modulus for a given beam

Equipment Required: Bending of beams apparatus, pan, weights, beam of different cross-sections

Learning Objectives: To practically visualize the bending of beams for different support

reactions, understand the importance of flexural rigidity and elastic modulus of beam

Outline of the Procedure: Adjust cast- iron block along the bed so that they are symmetrical

with respect to the length of the bed. Place the beam on the knife edges on the block so as to

project equally beyond each knife edge. See that the load is applied at the centre of the beam.

Note the initial reading of vernier scale. Add a weight of 20N (say) and again note the

reading of the vernier scale. Go on taking readings adding 20N (say) each time till you have

minimum six readings. Find the deflection () in each case by subtracting the initial readingof vernier scale. Draw a graph between load (W) and deflection () . On the graph choose any

two convenient points and between these points find the corresponding values of W and .

Calculate the value of E and the bending stresses for different loads.

Required Results:

Parameters:

1. The youngs modulus for steelbeam is found to be----- N/mm2.

2. The youngs modulus for wooden beam is found to be----- N/mm2

Graphs/Plots: Graph between load (W) and deflection ().

Error Analysis:

Cautions:

1. Make sure that beam and load are placed a proper position.

2. The cross- section of the beam should be large.

3. Note down the readings of the vernier scale carefully

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Aim: Verification of the bending equation and determination of flexural rigidity and elastic

modulus for a given beam

Observations:

S. No. Load Bending

moment

Bending

stress

Deflection Youngs

Modulus

Calculations:

Graphs attached:

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Error Analysis:

Learning Outcomes:


S.No

.


Marks



20


outcomes

20


Cleanliness

10


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Experiment: 3

Experiment: To perform torsion test on a specimen and find the modulus of rigidity of the

material

Equipment Required: A torsion testing machine, twist meter for measuring angles of twist,steel rule and Vernier caliper or micrometer.

Learning Objectives: To understand the concept of torsion, twist angle and torsional rigidity

Outline of the Procedure: Select the driving dogs to suit the size of the specimen and clamp

it in the machine by adjusting the length of the specimen by means of a sliding spindle.

Measure the diameter at about three places and take the average value. Choose the

appropriate range by capacity change lever. Set the maximum load pointer to zero. Set the

protector to zero for convenience and clamp it by means of knurled screw. Carry out straining

by rotating the handweel in either direction. Load the machine in suitable increments. Then

load out to failure as to cause equal increments of strain reading. Plot a torque- twist (T- )graph. Read off co-ordinates of a convenient point from the straight line portion of the torque

twist (T- ) graph and calculate the value of C by using relation

Required Results:

Parameters:

i) Modulus of rigidity of mild steel rod is ------------- N/mm2

ii) Modulus of rigidity of Aluminum rod is ------------- N/mm2

Graphs/Plots: Torque- twist (T- ) graph.

Error Analysis:

Cautions:

1) Measure the dimensions of the specimen carefully.

2) Measure the Angle of twist accurately for the corresponding value of Torque.

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Aim: To perform torsion test on a specimen and find the modulus of rigidity of the material

Observations:

Gauge length of the specimen, l = Diameter of the specimen, d =

Polar moment of inertia =

Torque

(T)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Angle of

twist()in

radians

Modulusof

rigidity

(C)

N/mm2

Calculations:

Graphs attached:

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Error Analysis:

Learning Outcomes:


S.No

.


Marks



20


outcomes

20


Cleanliness

10


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Experiment: 4

Experiment: To determine the hardness of a specimen material using Brinell's hardness test.

Equipment Required: Brinell's hardness testing machine, Brinell Microscope.

Material Required: Soft and hard mild steel specimens, brass, aluminum etc.

Learning Objectives: To understand the concept of hardness and the various hardness

numbers

Outline of the Procedure:

Specimen is placed on the anvil. The hand wheel is rotated so that the specimen along with

the anvil moves up and contact with the ball. The desired load is applied mechanically (by

gear driven screw) and the ball presses into the specimen. The diameter of the indentationmade in the specimen by the pressed ball is measured by the use of a micrometer microscope,

having transparent engraved scale in the field of view. The indentation diameter is measured

at two places at right angles to each other, and the average of two readings is taken. The

Brinell Hardness Number (BHN) which is the pressure per unit surface area of the

indentation is noted down.

Required Results:

Parameters:

The hardness of the material is found to be

Specimen 1 =

Specimen 2 =

Specimen 3 =

Error Analysis:

Cautions:

1. Brinell test should be performed on smooth, flat specimens from which dirt and scale have

been cleaned.

2. The test should not be made on specimens so thin that the impression shows through themetal, nor should impressions be made too close to the edge of the specimen.

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Aim: To determine the hardness of a specimen material using Brinell's hardness test.

Observations:

S. No.

Material Load DiameterOf the

Indenter in

mm

Diameter of theindentation in

mm

BrinellHardness

Number(BHN)

1 2 3

Calculations:


Error Analysis:

Learning Outcomes:


S.No

.


Marks



20


outcomes

20


Cleanliness

10


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Experiment: 5

Experiment: To determine the hardness of a specimen material using Rockwell hardness test

Equipment Required: Rockwell hardness testing machine

Material Required: Soft and hard mild steel specimens, brass, aluminum etc.

Learning Objectives: To understand the concept of hardness and the various hardness

numbers

Outline of the Procedure: Place the specimen securely upon the anvil. Elevate the specimen

so that it come into contact with the penetrator and put the specimen under a preliminary or

minor load of 100+2N without shock. Apply the major load 900N by loading lever. Watch

the pointer until it comes to rest. Remove the major load. Read the Rockwell hardness

number or hardness scale.

Required Results:

Parameters:

The hardness of the material is found to be

Specimen 1 =

Specimen 2 =

Specimen 3 =

Error Analysis:

Cautions:

1. Hardness test should be performed on smooth, flat specimens from which dirt and scale

have been cleaned.

2. The test should not be made on specimens so thin that the impression shows through the

metal, nor should impression be made too close to the edge of a specimen.

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Aim: To determine the hardness of a specimen material using Rockwell hardness test

Observation Table:

S. no. Material HRC reading Mean1 2 3

Calculations:


Error Analysis:

Learning Outcomes:


S.No

.


Marks



20


outcomes

20


Cleanliness

10


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Experiment: 6

Experiment: To determine the stiffness of spring, modulus of rigidity of the spring wire and

the maximum strain energy stored

Equipment Required: Spring testing machine, Vernier caliper, Scale, Micrometer.

Material Required: Spring

Learning Objectives: To understand the behaviour of springs subjected to loads,

significance of stiffness of spring, modulus of rigidity and the maximum strain energy stored


Measure the diameter of the wire of the spring by using the micrometer. Measure the

diameter of spring coils by using the vernier calliper. Count the number of turns. Insert the

spring in the spring testing machine and load the

spring by a suitable weight and note the corresponding axial deflection in tension orcompression. Increase the load and take the corresponding axial deflection readings. Plot a

curve between load and deflection. The shape of the curve gives the stiffness of the spring.

Required Results:

Parameters:

The value of spring constant k of closely coiled helical spring is

found to be------------ N / mm

Graphs/Plots: Graph between load and deflection.

Error Analysis:

Cautions:

1)The dimension of spring is to be measured accurately.

2) Deflection obtained in spring is measured accurately.

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Aim: To determine the stiffness of spring, modulus of rigidity of the spring wire and the

maximum strain energy stored

Observations:Least count of micrometer = mm

Diameter of the spring wire, d =mm

(Mean of three readings)

Least count of vernier caliper = mm

Diameter of the spring coil, D = mm

(Mean of three readings)

Mean coil diameter, Dm = D - dmm

Number of turns, n =

S.NO Load(N) Deflection(mm) Stiffness(N / mm)

Calculations:

Graphs attached:

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Error Analysis:

Learning Outcomes:


S.No

.


Marks



20


outcomes

20


Cleanliness

10


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Experiment: 7

Experiment: To perform the compression test on a specimen material and find the

compression strength

Equipment Required: Compression testing machine, Oven, Vernier Caliper, Scale,Etc.

Material Required: Bricks

Learning Objectives: Understanding of stress strain diagrams, compression strength of a

material, significance of Young's modulus

Outline of the Procedure: Select some brick with uniform shape and size. Measure its all

dimensions. (LXBXH) Now fill the frog of the brick with fine sand. And Place the brick on

the lower platform of compression testing machine and lower the spindle till the upper

motion of ram is offered by a specimen the oil pressure start increasing the pointer start

returning to zero leaving the drug pointer that is maximum reading which can be noted down.

Required Results:

Parameters:

The average compressive strength of new brick sample is

found to be . Kg/sq.cm.

Error Analysis:

Cautions:

1) Measure the dimensions of Brick accurately.

2) Specimen should be placed as for as possible in the of lower plate.

3) The range of the gauge fitted on the machine should not be more than double the breaking

load of specimen for reliable results.

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Aim: To perform the compression test on a specimen material and find the compression

strength

Observations:

S.No L X B XH

(Cm3)

Area

(Cm2)

Load

(N)

Compressive

Strength

(N/mm2)

Average

Compressive

Strength(N/mm2)

Calculations:

Graphs attached:

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Error Analysis:

Learning Outcomes:


S.No

.


Marks



20


outcomes

20


Cleanliness

10


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Experiment: 8

Experiment: To determine the impact strength of a specimen material using Charpy's test;

To determine the impact strength of a specimen material using Izod test

Equipment Required: Charpy's test apparatus, Izod test apparatus


Learning Objectives: To understand the concept of impact strength and the difference

between the two methods of determination of impact strength


(a) lzod test

With the striking hammer (pendulum) in safe test position, firmly hold the steel specimen in

impact testing machines vice in such a way that the notch face the hammer and is half inside

and half above the top surface of the vice. Bring the striking hammer to its top most strikingposition unless it is already there, and lock it at that position. Bring indicator of the machine

to zero, or follow the instructions of the operating manual supplied with the machine. Release

the hammer. It will fall due to gravity and break the specimen through its momentum, the

total energy is not absorbed by the specimen. Then it continues to swing. At its topmost

height after breaking the specimen, the indicator stops moving, while the pendulum falls

back. Note the indicator at that topmost final position. Again bring back the hammer to its

idle position and back

( b) Charpy Test

With the striking hammer (pendulum) in safe test position, firmly hold the steel specimen in

impact testing machines vice in such a way that the notch faces s the hammer and is half

inside and half above the top surface of the vice. Bring the striking hammer to its top most

striking position unless it is already there, and lock it at that position. Bring indicator of the

machine to zero, or follow the instructions of the operating manual supplied with the

machine. Release the hammer. It will fall due to gravity and break the specimen through its

momentum, the total energy is not absorbed by the specimen. Then it continues to swing. At

its topmost height after breaking the specimen, the indicator stops moving, while the

pendulum falls back. Note the indicator at that topmost final position. The specimen is placed

on supports or anvil so that the blow of hammer is opposite to the notch.

Required Results:Parameters:

The impact strength for the given material is _________ J/mm2

Error Analysis:

Cautions:

1. Measure the dimensions of the specimen carefully.

2. Hold the specimen (lzod test) firmly.

3. Locate the specimen (Charpy test) in such a way that the hammer, strikes it at the middle.

4. Note down readings carefully.

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Aim: To determine the impact strength of a specimen material using Charpy's test

To determine the impact strength of a specimen material using Izod test

Observations:Area of cross section of the given material:

(a) Charpy test

S.

No.

Material

Used

Energy

absorbed

by force

(A)

J

Energy spent to break the

specimen (B)

J

Energy

absorbed

by the

specimen

(A-B) J

Impact

Strength

J/mm2

(b) Izod test

S.

No.

Material

Used

Energy

absorbed

by force

(A)

J

Energy spent to break the

specimen (B)

J

Energy

absorbed

by the

specimen

(A-B) J

Impact

Strength

J/mm2

Calculations:

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Error Analysis:

Learning Outcomes:


S.No

.


Marks



20


outcomes

20


Cleanliness

10


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Experiment: 9

Experiment: To perform shear test on a specimen material using universal testing machine

Equipment Required: Universal Testing Machine, Scale, Vernier calliper, shear testing

attachment


Learning Objectives: Understanding of stressstrain diagrams, shear strength of a material,

significance of modulus of rigidity


Insert the specimen in position and grip one end of the attachment in the upper portion and

one end in the lower portion. Switch on the main switch of universal testing machine. The

drag indicator in contact with the main indicator. Select the suitable range of loads and space

the corresponding weight in the pendulum and balance it if necessary with the help of smallbalancing weights. Operate (push) buttons for driving the motor to drive the pump. Gradually

move the head control level in left-hand direction till the specimen shears. Down the load at

which the specimen shears. Stop the machine and remove the specimen Repeat the

experiment with other specimens.

Required Results:

Parameters:

The Shear strength of mild steel specimen is found to be = N/mm2

Error Analysis:

Cautions:

1 The measuring range should not be changed at any stage during the test.

2. The inner diameter of the hole in the shear stress attachment should be slightly greater than

that of the specimen.

3. Measure the diameter of the specimen accurately.

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Aim: To perform shear test on a specimen material using universal testing machine

Observation Table:

Diameter of the Rod, D = . mmCross-section area of the Rod (in double shear) = 2x /4x d2=. mm2

Load taken by the Specimen at the time of failure , W = .N

Calculations:


Error Analysis:

Learning Outcomes:


S.No

.


Marks



20


outcomes

20


Cleanliness

10


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Experiment: 10

Experiment: To find the fatigue strength of a specimen material by performing the fatigue

test

Equipment Required: Fatigue testing machine, Set of weights, Scale, Vernier calliper,Pencil / chalk.

Material Required: Fatigue testing specimen

Learning Objectives: To understand the behaviour of a material subjected to repeated or

continuous loads with respect to time, fatigue strength of a material

Outline of the Procedure: Measure the overall (L), gauge length (Ig) and diameter at the

middle portion (d) of the given specimen. Mark the centre of the specimen using pencil /

chalk and fix the specimen in the machine properly. Place a suitable weight (W) say, 50kg in

the weight in the weight hanger of the machine and release the cam so as to apply the

weight / load to the specimen. Measure the distance between centre of the specimen and

centre of the weight hanger (l). Calculate the bending stress, which will develop in the

specimen. Set the electrical counter of the machine to zero position and start the motor of the

machine. Record the number indicated on the electrical counter after the specimen failure.

Calculate the actual number of revolutions (N) under gone by the specimen during the test by

multiplying the number indicated on the electrical counter with constant of multiplication (i.e.

20) given by the manufacture. Fix another specimen of same material, size and shape in themachine. Repeat the steps from 3 to 8 with 20% decrease in weight at each time. Conduct at

least 5 tests for a given material with specimen of same material, size and shape. Plot a graph

between log Vs log N by taking log along Y axis and log N along x axis. Read the

value of stress corresponding to the knee of N curve, which will be the endurance limit

stress for the given specimen.

Required Results:

Parameters:

The endurance limit stress for the given material of the specimen -------------------N/mm2

Graphs/Plots: Plot a graph between log Vs log N

Error Analysis:

Cautions:

1 The measuring range should not be changed at any stage during the test.

2. Measure the lengths of the specimen accurately.

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Aim: To find the fatigue strength of a specimen material by performing the fatigue test

Observations :

1. Material of the specimen =

2. Overall length of the specimen, L = mm

3. Gauge length of the specimen. lg = mm

4. Diameter at the middle portion of the specimen,d = mm

5. Distance between centre of the specimen and centre

Of the weighthanger, l = mm

Sl.No. Weight(W) in

Moment

(M)

In Nmm

(w x l)

Bending

stress

In N/mm2

( = MY / I)

Indication

in

the counter

(P)

Actual No. of

revolutions

(N) ( p X 20)

Log Log N

kg N

Calculations:

Graphs attached:

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Error Analysis:

Learning Outcomes:


S.No

.


Marks



20


outcomes

20


Cleanliness

10


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