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  • 1

    UNIVERSITI TENAGA NASIONAL

    COLLEGE OF ENGINEERING

    DEPARTMENT OF MECHANICAL ENGINEERING

    MESB 333 ENGINEERING MEASUREMENT & LAB

    FINAL REPORT

    DEFLECTION OF A BEAM

    GROUP NUMBER : 1

    SECTION : 4A

    LECTURER : MS TAN EE SANN

    GROUP MEMBER :

    1. THARASYAN A/L JANARTHANAN (ME 091905)

    2. DARVINDER SINGH (ME 092093)

    3. LEE ENG LOY (ME 091813)

    4. BAVANI YUNNASOGARAM (ME 091824)

    5. NG SEK KENG (ME 091910)

    6. CHIA YONG NAN (ME 090840)

  • 2

    TABLE OF CONTENT

    Index Title Page

    1 Abstract

    3

    2 Objective

    4

    3 Theory

    4

    4 Procedure

    7

    5 Literature Review

    8

    6 Data and Observation

    16

    7 Result and Analysis

    18

    8 Discussion

    29

    9 Conclusion

    32

    10 Reference

    32

    11 Appendix

    33

  • 3

    ABSTRACT

    The main objective of this experiment has been achieved. The main of objective is to

    measure the deflection of different materials with certain load applied on it. The deflection of

    each material depends on its elasticity. Based on the tabulated data, it is known that wood draws

    the highest deflection compared to other materials such as brass, steel and aluminum. One of the

    reasons that other materials are said to be stronger is due to the modulus of elasticity of such

    material. Modulus of elasticity was calculated and shows that it is 19200N/mm. There were

    some errors occurred while conducting the experiment. Due to the error, the percentage error

    calculated is more than 50%. Based on the error, it can be concluded that the instruments used

    like dial gauge which has high sensitivity may have cause the readings to differ from the

    theoretical values of each materials. Assumption is being made for the uncertainty for force and

    deflection because the dial gauge instrument could not give 100% accuracy where the readings

    does not start at 0mm. Moreover, the weight is not being placed exactly at the center of the beam

    due to position of measuring device. The average reading was being taken to calculate the

    uncertainty of each material.

  • 4

    Objectives

    1. To investigate the relationship between load and deflection of a beam placed on two bear

    affected by a concentrated load at the center.

    2. To determine the modulus of elasticity of the materials.

    Theory

    The stress-strain behavior of brittle materials (e.g. ceramic, low toughness composite

    material) is not usually ascertained by tensile tests as outline in this project. A more suitable

    transverse bending test is most frequently employed, in which a rod specimen either a circular

    or rectangular cross section is bent until fracture using a three- or four-point loading technique.

    The assessments are conducted according to ASTM Standard C 1161, Standard Test Method

    for Flexural Strength of Advanced Ceramics at Ambient Temperature.

  • 5

    Simply supported beam with central point load

    For this arrangement, it can be shown that the deflection under the load

    i.e. maximum deflection

    EI

    Wl

    48

    3

    Where 12

    3bdI

    Beam compliance 3

    3

    4Ebd

    l

    W

    Determination of coefficient of elasticity

  • 6

    Calculations:

    Deflection formula for the load given above:

    I

    FLE

    EI

    FL

    4848

    33

    A determination of the flexural stress yields:

    4

    1

    LFFM

    W

    Mb

    b

    bb

    Where:

    = Deflection (mm.) E = Coefficient of Elasticity

    L = Span(mm.) I = Inertia Factor

    Mb = Moment of Flexure (Nmm) F1 = = Load occasioned by weight of load device

    =2.5N

    Wb = Resistance to Flexure (mm3) F = Load occasioned by additional weight (N)

    b = Flexural Stress (N/mm2)

  • 7

    Set of Apparatus

    i. Twist and Bend Test Machine MT 3005.

    ii. 4 types of materials, brass, copper, aluminium, and wood.

    iii. Dial Gauge

    Procedure

    i. The apparatus is set as shown in the diagram.

    ii. Load is placed on the center of the beam.

    iii. The dial gauge is then placed on the top of the hook that holds the load.

    iv. The load is added in increasing order from 5N, 10N, 15N and 25N.

    v. The readings are taken from the deflection of the dial gauge, and tabulated.

    vi. The different types of materials are tested on the bending machine (wood, aluminum,

    brass and copper.

  • 8

    Literature Review

    2.1 Apparatus

    The experiment was conducted on an apparatus that is simply designed to support at two separate

    ends to enable load to be applied at the centre of the placed material to read the deflection of the

    material for analysis.

    2.1.1 Twist and Test Machine MT 3005

    Realizing that the planned apparatus prototype in progress report 1 has the same general

    concept/idea as the one in the Materials Laboratory in UNITEN, we have decided to use the

    readily available instead.

    MT 3005 Twist and Bend Testing Machine

  • 9

    2.1.2 MT 3005 Utilization

    The MT 3005 is a very capable and versatile apparatus that can cater to several specific needs. It

    combines twist and bending capabilities and can be used in laboratory exercises in conjunction

    with theoretical work on twist and bending.

    2.1.3 MT 3005 Specifications

    Equipment Quantity

    Twist and Bending Machine 1

    Loading devices (0.25 Kg) 2

    1 Kg weights 2

    0.5 Kg weights 4

    Dial Gauge 1

    Rectangular cross-section steel test piece 7

    Rectangular cross-section wood test piece 1

    Diameter 8 mm, of resp. steel, aluminium and brass 3

    End fixtures 2

    Laboratory manual 1

  • 10

    2.1.4 Bending and Modulus of Elasticity

    For this experiment, bending is prioritized. Through bending, the modulus of elasticity of

    different materials is able to be determined. The test piece is supported at either end and load (in

    a form of weights) is applied in the middle between the supports.

    Example of calculation of modulus of elasticity

  • 11

    2.2 Materials

    A set of materials were chosen as the test specimen for this experiment. Each of which

    has 99% similarity in terms of dimensions of 375 mm x 31 mm x 6.3 mm. The following

    materials were tested.

    Material types: Aluminium, wood, brass & copper (top to bottom)

    2.2.1 Wood

    Wood is a hard, fibrous tissue found in many trees. It has been used for hundreds of

    thousands of years for both fuel and as a construction material. It is an organic material, a

    natural composite of cellulose fibers (which are strong in tension) embedded in

    a matrix of lignin which resists compression.

    The classification of wood has historically always been either hard wood; any leaf

    bearing tree, and soft wood; any cone bearing tree. These terms can be confusing since some leaf

    bearing trees can have very soft wood and some coniferous trees can have very hard woods. To

    make this easier, below you will find a list of different tree types, classification and then

    individual wood characteristics.

  • 12

    2.2.1.1 Wood Utilization

    Pound for pound, wood is stronger than steel. Unlike steel, it is also resilient. This

    combination of strength and resiliency gives wood the ability to absorb the shock of heavy loads

    providing a greater margin of safety than many other materials.

    Wood and wood-based products are the most important of all man's resources for three

    main reasons. First, wood is universal. It is a raw material that can satisfy almost every

    requirement or existence. It provides food for man and animals. It is one of the world's most

    important sources of textile fibers. Wood is capable of producing motor fuels and lubricants. As

    a building material, wood yields an astonishing variety of plywoods, plastic and wood fiber

    products that can meet any engineering specification.

    2.2.2 Aluminium

    Aluminium (or aluminum; see spelling differences) is a chemical element in the boron

    group with symbol Al and atomic number 13. It is a silvery white, soft, ductile metal. Aluminium

    is the third most abundant element (after oxygen and silicon), and the most abundant metal in

    the Earth's crust. It makes up about 8% by weight of the Earth's solid surface. Aluminium metal

    is so chemically reactive that native specimens are rare and limited to

    extreme reducing environments. Instead, it is found combined in over 270 different minerals.

    The chief ore of aluminium is bauxite.

    2.2.2.1 Aluminium Utilization

    Aluminium is remarkable for the metal's low density and for its ability to

    resist corrosion due to the phenomenon of passivation. Structural components made from

    aluminium and its alloys are vital to the aerospace industry and are important in other areas of

    transportation and structural materials. The most useful compounds of aluminium, at least on a

    weight basis, are the oxides and sulphates.

  • 13

    2.2.3 Brass

    Brass is an alloy made of copper and zinc; the proportions of zinc and copper can be

    varied to create a range of brasses with varying properties. It is a sub-stitutional alloy: atoms of

    the two constituents may replace each other within the same crystal structure.

    By comparison, bronze is principally an alloy of copper and tin. Bronze does not

    necessarily contain tin, and a variety of alloys of copper, including alloys

    with arsenic, phosphorus, aluminium, manganese, and silicon, are commonly termed "bronze".

    The term is applied to a variety of brasses and the distinction is largely historical, and

    modern practice in museums and archaeology is increasingly to avoid both terms for historical

    objects in favour of the all-embracing "copper alloy".

    2.2.3.1 Brass Utilization

    Brass is used for decoration for its bright gold-like appearance; for applications where

    low friction is required such as locks, gears, bearings, doorknobs, ammunition casings and

    valves; for plumbing and electrical applications; and extensively in brass musical instruments

    such as horns and bells for its acoustic properties. It is also used in zippers. Brass is often used in

    situations where it is important that sparks not be struck, as in fittings and tools around explosive

    gases.

    2.2.4 Copper

    Copper is a chemical element with the symbol Cu (from Latin: cuprum) and atomic

    number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is

    soft and malleable; a freshly exposed surface has a reddish-orange color. It is used as a conductor

    of heat and electricity, a building material, and a constituent of various metal alloys.

    The metal and its alloys have been used for thousands of years. In the Roman era, copper

    was principally mined on Cyprus, hence the origin of the name of the metal as yprium (metal of

    Cyprus), later shortened to uprum. Its compounds are commonly encountered as copper (II)

    salts, which often impart blue or green colors to minerals such as azurite and turquoise and have

    been widely used historically as pigments. Architectural structures built with copper corrode to

    give green verdigris (or patina). Decorative art prominently features copper, both by itself and as

    part of pigments.

  • 14

    2.2.4.1 Copper Utilization

    Copper is essential to all living organisms as a trace dietary mineral because it is a key

    constituent of the respiratory enzyme complexcytochrome c oxidase.

    In molluscs and crustacea copper is a constituent of the blood pigment hemocyanin,

    which is replaced by the iron-complexed hemoglobin in fish and other vertebrates. The main

    areas where copper is found in humans are liver, muscle and bone. Copper compounds are used

    as bacteriostatic substances, fungicides, and wood preservatives.

  • 15

    2.3 Material Properties

    Properties table including the 4 chosen materials with theoretical modulus of elasticity,

  • 16

    DATA & OBSERVATION

    Task 1: Load and Deflection

    Material Dimension (Length Width Height)

    Wood 375 31 6.4

    Aluminum 375 25 6.2

    Brass 375 25 6.2

    Copper 375 25 6.2

    Table 1 Dimension of each material

    Load

    (N)

    Deflection (mm)

    Wood Aluminum Brass Copper

    5 1.64 0.42 0.3 0.25

    10 3.11 0.84 0.56 0.48

    15 4.70 1.27 0.9 0.73

    25 8.53 2.10 1.52 1.20

    Table 2 Load and Deflection for each material

  • 17

    Task 2: Modulus of Elasticity

    Material

    Load,

    F (N)

    Moment of

    Flexure, Mb

    (Nmm)

    Flexural

    Stress

    Deflection Coefficient Of Elasticity

    b

    (N/mm2)

    (mm)

    E

    (N/mm2)

    Eave

    (N/mm2)

    Wood

    5 703.125 3.3225 1.64 18910.7500

    19200.5

    10 1171.875 5.5375 3.11 19934.9647

    15 1640.625 7.7524 4.70 19786.5128

    25 2578.125 12.1824 8.53 18170.4983

    Aluminum

    5 703.125 4.3900 0.42 26341.4343

    26289.6

    10 1171.875 7.3166 0.84 26341.4343

    15 1640.625 10.2432 1.27 26134.0215

    25 2578.125 16.0966 2.10 26341.4343

    Brass

    5 703.125 4.3900 0.3 36878.0081

    37415.3

    10 1171.875 7.3166 0.56 39512.1515

    15 1640.625 10.2432 0.9 36878.0081

    25 2578.125 16.0966 1.52 36392.7711

    Copper

    5 703.125 4.3900 0.25 44253.6097

    45478.7

    10 1171.875 7.3166 0.48 46097.5101

    15 1640.625 10.2432 0.73 45466.0374

    25 2578.125 16.0966 1.20 46097.5101

    Table 3 Modulus of Elasticity

  • 18

    ANALYSIS & RESULTS

    Graph 1 Deflection vs Loading

    Graph 2 Theoretical vs Experimental of Coefficient of Elasticity for each material

    0

    1

    2

    3

    4

    5

    6

    7

    8

    9

    5 10 15 25

    Def

    lect

    ion

    (m

    m)

    Load (N)

    Graph Deflection vs Loading

    Wood Aluminum Brass Copper

    0

    20

    40

    60

    80

    100

    120

    140

    Wood Aluminum Brass Copper

    Co

    effi

    cien

    t O

    f El

    ast

    icit

    y (G

    Pa

    )

    Material

    Theoretical vs Experimental forCoefficient of Elasticity

    Experrimental Theoretical

  • 19

    Calculation:

    To calculate the coefficient of elasticity of steel, brass, alumunium and wood, the deflection

    formula is:-

    EI

    FL

    48

    3

    I

    FLE

    48

    3

    To determine the flexural stress:-

    b

    bb

    W

    M

    4)( 1

    LFFM b

    When rectangular it is 12

    3bhI and

    6

    2bhWb

    = Deflection (mm)

    L = Span (mm) = 500 mm

    Mb = Moment of Flexures (Nmm)

    Wb = Resistance to Flexure (mm3)

    b = Flexural Stress (N/mm2)

    E = Coefficient of Elasticity

    I = Inertia Factor

    F1 = Load occasioned by weight of Load Device (N) = 2.5 N

    F = Load occasioned by additional weight (N)

  • 20

    Moment of flexure is the same for every specimen according to the load weight used.

    Moment of Flexure: 4

    )( 1L

    FFM b

    5 N NmmMb 125.7034

    375)5.25(

    10 N NmmMb 875.11714

    375)5.210(

    15 N NmmMb 625.16404

    375)5.215(

    25 N NmmMb 125.25784

    375)5.225(

    Flexural stress for wood:-

    Dimension: 31 6.4 mm

    322

    6267.2116

    4.631

    6mm

    bhWb

    5 N 23225.36267.211

    125.703

    mmN

    b

    10 N 25375.56267.211

    875.1171

    mmN

    b

    15 N 27524.76267.211

    625.1640

    mmN

    b

    20 N 21824.126267.211

    125.2578

    mmN

    b

  • 21

    Flexural stress for Aluminum, Brass and Copper :-

    Dimension: 25 6.2 mm

    322

    1667.1606

    2.625

    6mm

    bhWb

    5 N 23900.41667.160

    125.703

    mmN

    b

    10 N 23166.71667.160

    875.1171

    mmN

    b

    15 N 22432.101667.160

    625.1640

    mmN

    b

    20 N 20966.161667.160

    125.2578

    mmN

    b

    Inertia Factor for Wood:

    433

    2053.67712

    4.631

    12mm

    bhI

    Inertia Factor for Aluminum, Brass, and Copper::

    433

    5167.49612

    2.625

    12mm

    bhI

  • 22

    Modulus of Elasticity:

    Wood:-

    5 N GPammNI

    FLE 9018.187500.18901

    64.12053.17748

    3755

    48

    233

    10 N GPammNI

    FLE 9350.199647.19934

    11.32053.17748

    37510

    48

    233

    15 N GPammNI

    FLE 7865.195128.19786

    70.42053.17748

    37515

    48

    233

    25 N GPammNI

    FLE 1705.184983.18170

    53.82053.17748

    37525

    48

    233

    Uncertainty:

    5 N ()5 = [ (

    )2(

    =1 )

    2 ] = [(0.02)2(5)2 + (0.02)2(1.64)2]0.5 = 0.1053

    10N ()10 = [ (

    )2(

    =1 )

    2 ] = [(0.02)2(10)2 + (0.02)2(3.11)2]0.5 = 0.2095

    15N ()15 = [ (

    )2(

    =1 )

    2 ] = [(0.02)2(15)2 + (0.02)2(4.70)2]0.5 = 0.3143

    25N ()25 = [ (

    )2(

    =1 )

    2 ] = [(0.02)2(25)2 + (0.02)2(8.53)2]0.5 = 0.5283

    Hence, GPaEave 2005.194

    1765.187865.199350.199018.18

    Hence, () = 0.1053+0.2095+0.3143+0.5283

    4 = 0.2894 GPa

  • 23

    = 19.2005 0.2894

    Theoretical Value = 12.5 GPa

    % error = %604.531005.12

    2005.195.12

    % error = %2888.511005.12

    )2894.02005.19(5.12

    Aluminum:-

    5 N GPammNI

    FLE 3414.264343.26341

    42.05167.49648

    3755

    48

    233

    10 N GPammNI

    FLE 3414.264343.26341

    84.05167.49648

    37510

    48

    233

    15 N GPammNI

    FLE 1340.260215.26134

    27.15167.49648

    37515

    48

    233

    25 N GPammNI

    FLE 3414.264343.26341

    10.25167.49648

    37525

    48

    233

  • 24

    Uncertainty:

    5 N ()5 = [ (

    )2(

    =1 )

    2 ] = [(0.02)2(5)2 + (0.02)2(0.42)2]0.5 = 0.1005

    10N ()10 = [ (

    )2(

    =1 )

    2 ] = [(0.02)2(10)2 + (0.02)2(0.84)2]0.5 = 0.2007

    15N ()15 = [ (

    )2(

    =1 )

    2 ] = [(0.02)2(15)2 + (0.02)2(1.27)2]0.5 = 0.3010

    25N ()25 = [ (

    )2(

    =1 )

    2 ] = [(0.02)2(25)2 + (0.02)2(2.10)2]0.5 = 0.5018

    Hence, GPaEave 2896.264

    3414.261340.263414.263414.26

    Hence, () = 0.1005+0.2007+0.3010+0.5018

    4= 0.2760

    = 26.2896 0.2760

    Theoretical Value = Range of 69 GPa

    % error = %8991.6110069

    2896.2669

    % error = %4991.6110069

    )2760.02896.26(69

  • 25

    Brass:-

    5 N GPammNI

    FLE 8780.360081.36878

    3.05167.49648

    3755

    48

    233

    10 N GPammNI

    FLE 5122.391515.39512

    56.05167.49648

    37510

    48

    233

    15 N GPammNI

    FLE 8780.360081.36878

    9.05167.49648

    37515

    48

    233

    25 N GPammNI

    FLE 3928.367711.36392

    52.15167.49648

    37525

    48

    233

    Uncertainty:

    5 N ()5 = [ (

    )2(

    =1 )

    2 ] = [(0.02)2(5)2 + (0.02)2(0.30)2]0.5 = 0.1000

    10N ()10 = [ (

    )2(

    =1 )

    2 ] = [(0.02)2(10)2 + (0.02)2(0.56)2]0.5 =

    0.2002

    15N ()15 = [ (

    )2(

    =1 )

    2 ] = [(0.02)2(15)2 + (0.02)2(0.90)2]0.5 =

    0.3005

    25N ()25 = [ (

    )2(

    =1 )

    2 ] = [(0.02)2(25)2 + (0.02)2(2.10)2]0.5 =

    0.5009

    Hence, GPaEave 4153.374

    3928.368780.365122.398780.36

    Hence, () = 0.1000+0.2002+0.3005+0.5009

    4= 0.2754

  • 26

    = 37.4153 0.2754

    Theoretical Value = Range of 102 to 125 GPa

    % error = %3183.6310000.102

    4153.3700.102

    % error = %0483.6310000.102

    )2754.04153.37(00.102

    Copper:-

    5 N GPammNI

    FLE 2536.446097.44253

    25.05167.49648

    3755

    48

    233

    10 N GPammNI

    FLE 0975.465101.46097

    48.05167.49648

    37510

    48

    233

    15 N GPammNI

    FLE 4660.450374.45466

    73.05167.49648

    37515

    48

    233

    25 N GPammNI

    FLE 0975.465101.46097

    20.15167.49648

    37525

    48

    233

  • 27

    Uncertainty:

    5 N ()5 = [ (

    )2(

    =1 )

    2 ] = [(0.02)2(5)2 + (0.02)2(0.25)2]0.5 = 0.1000

    10N ()10 = [ (

    )2(

    =1 )

    2 ] = [(0.02)2(10)2 + (0.02)2(0.48)2]0.5 = 0.2002

    15N ()15 = [ (

    )2(

    =1 )

    2 ] = [(0.02)2(15)2 + (0.02)2(0.73)2]0.5 = 0.3003

    25N ()25 = [ (

    )2(

    =1 )

    2 ] = [(0.02)2(25)2 + (0.02)2(1.20)2]0.5 = 0.5006

    Hence, GPaEave 4787.454

    0975.464660.450975.462536.44

    Hence, () = 0.1000+0.2002+0.3003+0.5006

    4= 0.2753

    = 37.4153 0.2753

    Theoretical Value = 117 GPa

    % error = %1293.6110000.117

    4787.4500.117

    % error = %8940.6010000.117

    )2753.04787.45(00.117

  • 28

    Standard Deviation:

    For 5N:

    =()

    =1.64 + 0.42 + 0.3 + 0.25

    4

    = 0.6525mm

    = ( )

    = [(1.64 0.6525)2 + (0.42 0.6525)2 + (0.3 0.6525)2 + (0.25 0.6525)2]

    4

    = 0.5734

    For 10N:

    =()

    =3.11 + 0.84 + 0.56 + 0.48

    4

    = 1.2475

    = ( )

    = [(3.11 1.2475)2 + (0.84 1.2475)2 + (0.56 1.2475)2 + (0.48 1.2475)2]

    4

    = 1.0836

  • 29

    Discussion

    1. Why deflection occurs during the applied of the load?

    In the field of engineering, deflection is understood as the degree to which a structural

    element is displaced under a load. It may refer to an angle or a distance. [1] To make it

    simple, when a force or a load acting towards a point of a bar, where the bar is placed in a

    horizontal way, deflection will occur and can be clarified by using naked eye only. The

    deflection distance of a member under a load is directly related to the slope of the deflected

    shape of the member under that load and can be calculated by integrating the function that

    mathematically describes the slope of the member under that load. It can normally be

    calculated by using Euler or Bernoulli beam equation.

    2. Why different materials will be getting different values from deflection, although the load

    applied is the same?

    In the graph obtained, there were four types of material used in this experiment,

    wood, aluminum, brass and copper; one of the reasons to use different type of material was

    to justify the theory of bending was depend on the type of material. From the result

    obtained from the experiment, the material which deflection occur the most was wood.

    The result is 1.64mm, 3.11mm, 4.70mm and 5.83mm. Wood is a hard, fibrous structural

    tissue found in the stems and roots of trees and other woody plants. It has been used for

    thousands of years for both fuel and as a construction material [1], it is an organic material.

    It is a very soft type of material compared to other materials, e.g. copper. In this

    experiment, copper is the strongest element. This is been proven that the deflection

    obtained from the experiment is 0.25mm, 0.48mm, 0.73mm, 1.20mm. In short, it can be

    concluding that the stronger the material, the better the resistant towards deflection.

  • 30

    3. The comparison of coefficient of elasticity, E.

    In the Coefficients of Elasticity, E, of 4 different specimens was determined. Again

    the same apparatus as in task 1 is used. After experiments are done and after calculation,

    E for copper is obtained as 45478.7 GPa. This count to a percentage error of 61.12%

    from the theoretical value which is 117 GPa. E for brass is found to be 37.41 GPa, with

    an error of only 63.31% from theoretical value of 102 GPa. Aluminium has a theoretical

    E of 69GPa, however, from the experiment, it is 26.28 GPa. The percentage error will be

    61.89%. Finally E of wood was found to be 19.2GPa, an error of 53.60% from the actual

    value of 12.5 GPa.

    4. The uncertainty of the experiment.

    In physical experiments uncertainty analysis, or experimental uncertainty

    assessment, deals with assessing the uncertainty in a measurement. An experiment

    designed to determine an effect, demonstrate a law, or estimate the numerical value of a

    physical variable will be affected by errors due to instrumentation, methodology,

    presence of confounding effects and so on. Experimental uncertainty estimates are

    needed to assess the confidence in the results. [3] In this experiment, the overall

    uncertainty is calculated in average of 0.09 ~ 0.1 Pa. This result means that the average

    value for modulus of elastic is around 0.09 ~ 0.1 Pa from the experimental value. For

    example, the modulus of elastic experimental for wood material was 19.2005 GPa and

    around 0.09 ~ 0.1 Pa.

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    5. What are the errors occurred during the experiment?

    No measurement can be made perfect accuracy and precision. Therefore, it is

    instructive to know the various types of errors and uncertainties that are in general,

    associated with measurement system. [2] There are different types of error such as

    systematic error, miscellaneous type of gross errors and so on. First of all, the main error

    will be the instrument error which under the category of systematic error. The testing

    device which is the gauge has zero error. In other words, the measurement will never get

    a correct result due to the factor. Also, errors due to faulty adjustment are one of the

    factors. During the process of applying load, the equipment itself being touched

    unconsciously which will affect the result. Last but not least, the parallax error is also the

    reason why the results are not accurate. The way the reading being taken was not in a

    correct position where it has affected the result. All this factors will explain why the

    percentage error of this experiment is out of charge.

    6. Calibration for the experiment.

    Calibration is a comparison between measurements between known magnitude

    with another device and another experiment made in as similar a way as possible with a

    second device. In the experiment, three measuring gauge is in use for calibration purpose.

    It is for comparing the results in order to get the accurate value. E.g. the value of

    deflection of wood has been measured by three different measuring gauge. The value

    difference was only 0.2 0.4mm. So, the in between results have been taken it is the

    more accurate result.

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    CONCLUSION

    This experiment was conducted to observe the deflection of different material when it

    experiences applied load. Wood experienced the most deflection in comparison to copper which

    experience the least deflection. From analyzing the results obtained copper has the highest

    average modulus of elasticity which was 45478.7N/mm2 followed by brass 37415.3 N/mm2,

    aluminum 26289.6 N/mm2 and finally wood 19200.5 N/mm2 in decreasing modulus of elasticity.

    The experiment conducted reveals high percentage error when compared to the theoretical

    modulus of elasticity of studied materials. These errors may have been caused due to reasons

    such as human errors as well as instrumental errors that were discussed above; future

    experiments should take extra precautions to eliminate these errors to obtain more precise data.

    Uncertainty analysis carried out shows that wood has the highest uncertainty value for modulus

    of elasticity with 0.289GPa followed by aluminum at 0.2760GPa, Brass 0.2754GPa and Copper

    0.2753GPa in decreasing order. Hence the value of uncertainty is too small and hence does not

    significantly affect the data obtained.

    References

    [1] http://en.wikipedia.org/wiki/Deflection_(engineering).

    [2] B. C. Nakra. and K. K. Chaudhry, Instrumentation Measurement and Analysis, 3rd Ed.,

    McGraw Hill Education (India) Private Limited, 2009.

    [3] http://user.engineering.uiowa.edu/~cfd/pdfs/References/uncert.pdf

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    Appendix

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    -p.s: Lee Eng Loy was the photographer.