Tensile TEST LAB REPORT PDF

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FACULTY OF MECHANICAL ENGINEERING _____________________________________________________________________ _________ Programme : Bachelor of Engineering (Hons) Mechanical(EM220) Course : Applied Mechanics Lab Code : MEC 424 Lecturer : MEC 424 Group : EMD4M3B _____________________________________________________________________ _________ MEC 424 - LABORATORY REPORT TITLE: TENSILE TEST

NO

NAME

STUDENT ID

1.

MUHAMMAD HAKIM BIN ROSLAIN

2019696032

2.

MUHAMMAD RASYIDDIN BIN ABD RAUF

2019631124

3.

NICHOLAS SABAN ANAK JEASLY JANGGUT

2019695848

4.

NUR A'DANI SHAHMINA BINTI NOOR AZHAR

2019631122

5.

NUR ARIFAH BINTI MOHD KAMIL

2019630636

REPORT SUBMISSION:

17/5/2020

(DATE)

*By signing above you attest that you have contributed to this submission and confirm that all work you have contributed to this submission is your own work. Any suspicion of copying or plagiarism in this work will result in an investigation of academic misconduct and may result in a “0” on the work, an “F” in the course, or possibly more severe penalties.

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Marking Scheme

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ABSTRACT Tensile test is the analysis of design structures that are related to deformation caused by the applied forces. In the engineering field, study of the material is very important in the construction to ensure safety of the structures. By conducting the tensile test, the stress and strain can be determined. The tensile test is the study of deformation in the structural members such as rod, bar or plate. The stress-strain diagram from the test will determine whether the structural members either have permanent or elastics deformation. Through the experiment, the critical stress for the material can be determined. In this experiment, the specimen used is mild steel. The load applied to the experiment will be increased until the specimen becomes fractured. The energy to make the specimen fracture can be calculated through the relation of strain, stress and loads

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TABLE OF CONTENTS

MEC 424 - LABORATORY REPORT TITLE: TENSILE TEST

1 1

ABSTRACT

2

TABLE OF CONTENTS

3

LIST OF TABLES

4

LIST OF FIGURES

4

INTRODUCTION

5

THEORY

6

EXPERIMENTAL PROCEDURES AND APPARATUS

8

RESULTS

9

DISCUSSION

15

CONCLUSION

16

REFERENCES

17

APPENDICES

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3

LIST OF TABLES

Table 1 : Recorded and calculated dat 12

LIST OF FIGURES

Figure 1: Stress-strain graph 12 Figure 2: Figure2: Sketch of mild steel specimen

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Figure 3: Figure 3: Graph Stress – stress diagram

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Figure 4: Graph Load vs deformation

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INTRODUCTION An important aspect of the analysis and design of structures relates to the deformations caused by the loads applied to a structure. It is important to avoid deformations that may prevent the structure from fulfilling the purpose for which it was intended.

In this experiment, we will consider the deformations of a structural member under axial loading. A tensile test is conducted on a specimen of the material in order to obtain the stress-strain diagram. From this diagram, some important properties of the material such as its modulus of elasticity and whether the material is ductile or brittle can be determined. In fact, we can also determine whether the strains in the specimen will disappear after the load has been removed, when the material is said to behave elastically or whether a permanent set or plastic deformation will result.

Plotting the stress against the strain results in a curve that is characteristic of the properties of the material but does not depend upon the dimensions of the specimen used. This curve is called a stress-strain diagram. The yield stress, ultimate tensile stress, necking and fracture point of materials can all be determined from the diagram.

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THEORY TENSILE TEST Tensile test is a method used to measure the strength of a material by giving a static load on uniaxial direction of the specimen. The following is the scheme of the tensile test: The mild steel that is being tested is given some force in two directions, which is in uniaxial direction. The mild steel would experience a stretch and an elongation until it fracture or break. The diameter of the mild steel is 6.5mm. The length of the mild steel is 193mm. The elongation of the mild steel after it fracture or break is 4.2mm.. MECHANICAL PROPERTIES FROM TENSILE TEST 1. Yield strength - Determine the stress of mild steel due to elastic limit. It is the maximum load that obtained by the material when it is in between of elastic deformation and plastic deformation. 2. Tensile strength – It is the maximum load that can be hold by the mild steel before it experiencing necking phenomenon. Necking happens when the gage of the mild steel is starting to decrease. The tensile strength happens in the plastic regime. 3. Modulus of elasticity – Modulus of elasticity of young modulus is a measurement of resistant of the material due to elastic deformation. It shows the stiffness of the material. 4. Toughness – Measures the energy that is needed for material to fracture. If a test specimen is subjected to an axial load P, as shown in figure below, and if the load is increased in increments from zero to the point of fracture, and the stress and strain are computed at each step, a stress-shear curve as shown below:

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Figure 1 Stress-strain graph The curve is typical of class of steel known as mild steel. The relationship between stress and strain is linear up to proportional limit, the material is said to follow the Hooke’s Law until point yield, namely Proportional Limit. After this point, Hooke’s Law would not happen although the material has an Elastic Characteristic. The point B called Elastic Limit. The elastic limit of the material is a stress that lies between the proportional limit and the upper yield point up to this stress, the specimen can be unloaded without permanent deformation; the unloading will be along the linear portion of the diagram, the same path followed during loading. This part of the stress-strain diagram is called the elastic range. However, the Elastic Limit is seldom determined, since it is very close to the Proportional Limit and therefore rather difficult to detect.

A peak value, the upper yield point at the peak of yield line, is quickly reached after that, followed by leveling off at the lower yield point. At this stage of loading, the test specimen continues to elongate as long as the load is not removed, even though the load cannot be increased. This constant stress region is called Plastic Range. When a further load is applied to the specimen, the curve will rise continuously but became flatter until it reaches a maximum stress referred as the Ultimate Stress . Throughout the test, while the specimen is elongating, its cross-sectional area will decrease. At the Ultimate Stress, the cross-sectional area begins to decrease in a localized region of the specimen, instead of over the specimen’s entire gauge length. This phenomenon is caused by slip planes formed within the material and the actual strains produced are caused by shear stress. As a result, a construction or neck gradually tends to form this region(UTS).

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APPARATUS The apparatus that is used in this experiment are: 1. Tensile test machine 2. Mild steel 3. Vernier caliper

EXPERIMENTAL PROCEDURES 1. Measured the length of specimens using Vernier calliper. 2. Measure the thickness and width of specimens. 3. Mount the specimens to the jaw grip of tensile test machine. Slightly Stretch on specimen by turning load anchor clockwise until gauge record a slight reading. 4. Place extensometer on the vertical flat of inner jaw to record elongation of the specimen. Extensometer is set zero. 5. Turn the load anchor is clockwise direction until extensometer records a change of 0.1 mm. Record the load gauge reading. 6. Repeat step 5 for rate change in elongation to 0.2 mm and 0.3 mm. 7. Change the rate gradually to 0.1, when a load gauge recorded decreasing in reading until specimen break. 8. Measure the final length.

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RESULT

Figure2: Sketch of mild steel specimen 700 600

Stress(Pa)

500 400 300 200 100 0 0

0.02

0.04

0.06

0.08

0.1

0.12

Strain

Figure 3: Graph Stress – stress diagram

25000

20000

Load(N)

15000

10000

5000

0 0

1

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Elongation(mm)

Figure 4: Graph Load vs deformation 9

Table 1: Recorded and calculated data. Extension mm 0.00000000 0.03497685 0.06995371 0.10516970 0.13996720 0.17500380 0.21010030 0.24495750 0.27993440 0.31515040 0.34994790 0.38498450 0.42014080 0.45493830 0.48991510 0.52513110 0.55980900 0.59514460 0.63000190 0.66491890 0.70007520 0.73505200 0.76990920 0.80506550 0.83998250 0.87489960 0.91005580 0.94497290 0.97994980 1.01504600 1.05002300 1.08488000 1.12015600 1.15501300 1.18993000 1.22508700 1.25994400 1.29492100 1.33007700 1.36493400 1.39997100 1.43500800 1.46998400 1.50490100 1.54011800 1.57491500

Load N 2.428644 43.79144 48.89359 49.91779 48.67112 49.30481 49.42594 50.88846 54.7432 62.94259 110.3375 282.8532 659.235 1177.249 1687.969 2133.302 2524.197 2889.435 3219.476 3518.681 3800.108 4068.359 4328.976 4590.371 4840.70 5090.894 5355.458 5621.289 5891.222 6170.47 6456.427 6740.838 7040.39 7341.693 7644.905 7963.158 8283.041 8606.084 8937.941 9268.539 9602.85 9946.99 10291.92 10638.52 10997.15 11352.21

stress 0.07319 1.3197 1.47345 1.50432 1.46675 1.48585 1.4895 1.53357 1.64974 1.89683 3.32512 8.52404 19.8666 35.4775 50.8685 64.289 76.069 87.0758 97.0218 106.039 114.52 122.604 130.458 138.335 145.879 153.419 161.392 169.403 177.537 185.953 194.57 203.141 212.169 221.249 230.386 239.977 249.617 259.352 269.353 279.316 289.391 299.762 310.156 320.602 331.409 342.109

strain 0.0000000 0.0006662 0.0013325 0.0020032 0.002666 0.0033334 0.0040019 0.0046659 0.0053321 0.0060029 0.0066657 0.0073330 0.0080027 0.0086655 0.0093317 0.0100025 0.0106630 0.0113361 0.0120000 0.0126651 0.0133348 0.0140010 0.0146649 0.0153346 0.0159997 0.0166648 0.0173344 0.0179995 0.0186657 0.0193342 0.0200004 0.0206644 0.0213363 0.0220002 0.0226653 0.0233350 0.0239989 0.0246652 0.0253348 0.0259987 0.0266661 0.0273335 0.0279997 0.0286648 0.0293356 0.0299984 10

1.60995200 1.64510800 1.679965 1.714882 1.750098 1.784896 1.819992 1.855089 1.889946 1.925042 1.960019 1.994936 2.029973 2.065069 2.099867 2.135023 2.17006 2.204857 2.240073 2.27511 2.309907 2.345064 2.38004 2.414898 2.450054 2.485031 2.519948 2.555044 2.590021 2.624938 2.660094 2.695011 2.729869 2.765144 2.799942 2.834919 2.870075 2.904992 2.939969 2.975125 3.009923 3.045019 3.080115 3.114972 3.149949 3.185106 3.219963 3.25494

11711.88 12082.15 12450.55 12821.87 13208.54 13589.74 13972.63 14364.9 14747.86 15139.59 15534.02 15923.46 16312.88 16711.22 17093.2 17480.47 17858.04 18206.85 18527.56 18798.14 18979.65 19099.58 19167.41 19201.69 19232.63 19260 19278.02 19305.52 19326.23 19342.09 19365.01 19384.25 19395.2 19416.3 19429.16 19437.66 19454.98 19463.89 19470.56 19484.08 19484.59 19493.52 19504.36 19506.37 19510.37 19518.72 19518.52 19521.08

352.948 364.107 375.209 386.399 398.051 409.539 421.078 432.899 444.44 456.245 468.132 479.868 491.604 503.608 515.119 526.79 538.168 548.68 558.345 566.499 571.969 575.583 577.627 578.66 579.593 580.418 580.961 581.789 582.414 582.892 583.582 584.162 584.492 585.128 585.515 585.772 586.294 586.562 586.763 587.171 587.186 587.455 587.782 587.842 587.963 588.214 588.208 588.286

0.0306658 0.0313354 0.0319993 0.0326644 0.0333352 0.033998 0.0346665 0.035335 0.035999 0.0366675 0.0373337 0.0379988 0.0386662 0.0393346 0.0399975 0.0406671 0.0413345 0.0419973 0.0426681 0.0433354 0.0439982 0.0446679 0.0453341 0.0459981 0.0466677 0.0473339 0.047999 0.0486675 0.0493337 0.0499988 0.0506685 0.0513335 0.0519975 0.0526694 0.0533322 0.0539985 0.0546681 0.0553332 0.0559994 0.056669 0.0573319 0.0580004 0.0586689 0.0593328 0.059999 0.0606687 0.0613326 0.0619989 11

3.290156 3.324894 3.35999 3.395086 3.430004 3.46498 3.500256 3.534874 3.570031 3.605127 3.639984 3.675021 3.710057 3.744915 3.780011 3.815108 3.849905 3.885061 3.920098 3.954895 3.990051 4.025029 4.059946 4.095102 4.129959 4.164936 4.200152 4.234949 4.269986 4.305083 4.33994 4.374976 4.410073 4.44499 4.479967 4.515123 4.549921 4.584957 4.620113 4.654971 4.689947 4.725104 4.759961 4.794938 4.830154 4.864951 4.899988 4.935084

19527.38 19521.81 19518.34 19516.61 19504.9 19488.7 19479.62 19445.55 19419.37 19385.07 19339.68 19289.58 19242.78 19176.47 19116.47 19058.04 18982.73 18916.17 18848.51 18766.9 18697.31 18625.03 18539.09 18466.32 18388.37 18300.88 18225.63 18140.9 18055.2 17976.7 17888.83 17802.9 17721.46 17633.7 17541.28 17460.2 17367.72 17276.08 17189.65 17095.49 16998.41 16908.7 16809.84 16711.84 16616.89 16513.04 16408.19 16311.3

588.475 588.308 588.203 588.151 587.798 587.31 587.036 586.009 585.22 584.187 582.819 581.309 579.899 577.9 576.092 574.331 572.062 570.056 568.017 565.558 563.461 561.282 558.692 556.499 554.15 551.514 549.246 546.693 544.11 541.744 539.096 536.507 534.052 531.408 528.622 526.179 523.392 520.63 518.026 515.188 512.263 509.559 506.58 503.627 500.765 497.636 494.476 491.556

0.0626696 0.0633313 0.0639998 0.0646683 0.0653334 0.0659996 0.0666715 0.0673309 0.0680006 0.0686691 0.069333 0.0700004 0.0706678 0.0713317 0.0720002 0.0726687 0.0733315 0.0740012 0.0746685 0.0753313 0.076001 0.0766672 0.0773323 0.0780019 0.0786659 0.0793321 0.0800029 0.0806657 0.0813331 0.0820016 0.0826655 0.0833329 0.0840014 0.0846665 0.0853327 0.0860023 0.0866652 0.0873325 0.0880022 0.0886661 0.0893323 0.090002 0.0906659 0.0913322 0.0920029 0.0926657 0.0933331 0.0940016 12

4.970001 5.004978 5.040134 5.074932 5.109968 5.145125 5.179862 5.215019 5.250115 5.284913 5.320009 5.355105 5.389962 5.425119 5.45609

16201.94 16096.25 15993.52 15878.42 15768.25 15659.41 15539.06 15422.51 15307.43 15177.78 15055.25 14928.1 14787.35 14648.4 4230.027

488.26 485.075 481.979 478.511 475.191 471.911 468.284 464.771 461.303 457.396 453.704 449.872 445.63 441.443 127.476

0.0946667 0.0953329 0.0960026 0.0966654 0.0973327 0.0980024 0.098664 0.0993337 0.1000022 0.100665 0.1013335 0.102002 0.1026659 0.1033356 0.1039255

Calculation of the result : The calculation of the data to determine stress and strain of the result are done by the excel. Length of mild steel= 193 mm Gauge length= 52.5 mm Diameter= 6.5mm Area(A)= πd2/4 =π(6.5 x 10-3)2/4 =3.3183 × 10-5 M2 Stress; σ= P/A P=Load/force (N) σ= 2.428644/3.3183 × 10-5 = 0.07319 N/ M2 Strain; ϵ=ΔL/L ΔL= change in length L=initial length =52.5mm ϵ = 0.03497685 mm/ 52.5mm = 0.0006662 13

Characteristic of mild steel Mild steel is the steel alloy which have high volume of steel in production. Theoretically, mild steel have 210 GPa of modulus of elasticsity. Mild steel have excellent strength because the metal have low amount pf carbon. Mild steel also have high ductility which make it high resistance against breakage. Mild steel also have good ductility which make the metal can be used easily in work and also the forming process of the mild steel will be easy. The reason of the mild steel have excellent characteristic is because the metal have excellent material properties that suitable for design construction. Even though mild steel have a lot of excellent properties, but the metal have poor resistance toward corrosion. Corrosion in the mild steel will change the strength of the metal. The corrosion can be prevented by painting the metal. Actual energy to break the specimen: From this experiment, the actual energy for the specimen to break during the tensile test can be calculated. To calculate the actual energy, the data will be taken will be from loaddeformation diagram. Before begin the calculation, there is few assumption should be made which is we should assume the line in the elastics region of load-deformation diagram directly proportional and the factor of safety assume to be 1. This is because, the calculation the actual diagram will involve the integration of data. The actual energy can be determined by using the area under the graph. Actual energy: U= PL/2 U= (15000 x 0.0025)/2 =45 N.M The actual energy calculated by using this method not really accurate due to the factor of safety was ignore and also due to the assumption that has been made.

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DISCUSSION The mild steel specimen that was tested in the tensile test experiment was followed the international standards. This is because the experiment conducted according to the standard procedure for tensile test experiment. For example, specimen have threaded grip to mate the holder of tested machine. There are few types of grips such as serrated wedges and spit collar. The dimension of mild steel also followed the standard dimension such as gage length, diameter of specimen along the gage specimen and length or reduced specimen. The tensile test also conducted under room temperature. Conducting the tensile test by following the international standard will make the experiment come out with the desired result. This will make the percentage of errors between theoretical and the experiment can be reduced. The percentage of errors can be reduced in the experiment if the experiment conducted under excellent precaution. The experiment should be set up according to the procedure that as provided. Set the system in the computer software with correct setting option. Make sure the testing machine work properly or have regular maintenance so that the data can be collected more accurate. The experiment should be conducting under room temperature to maintain the actual properties of the specimen. The broken specimen of mild steel occur at the gage region during the tensile test. Before the mild steel specimen got broken, the specimen will experiencing necking in the gage area. The rupture of mild steel specimen occur along a cone shaped surface that form approximately forty five degree with the original surface of the specimen. The rupture of mild steel specimen because of shear stress. The specimen was experiencing necking before rupture is ductile material. Ductile materials have high modulus of elasticity that make the material elongate when applied to the tensile force.

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CONCLUSION The experiment was conducted under the Standard International either procedure or the materials parameters so that the result can be minimize the percentage of errors. From the experiment, the mild steel can be concluded as ductile material. This is because the mild steel specimen elongated and necking before rupture. Mild steel have high modulus of elasticity which make mild steel specimen can form the elastic deformation if the tensile force applied not reached the ultimate strength. The most important data to be recorded in the experiment is the elongation of the mild steel specimen. This is because the mechanical properties of the materials can concluded and justify from the graph...