Richard Garrison Material Science Lab 1

8/9/2019 Richard Garrison Material Science Lab 1

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Abstract

The Tensile Test is used to create a Stress-Strain curve from the

application of force on both ends of a sample of material. From the Stress-

Strain graph constructed several properties can be measured or concluded

about the data. For this particular experiment it was necessary to determine

Young’s Modulus yield strength ductility and brea!ing strength of "#$S

$lastic %rass and Steel samples. &ach material endured three trials to

obtain more accurate data. %efore hand it was necessary to measure the

dimensions of each sample before inducing stress upon it in order to have

initial values for ' &longation calculations. (fter conducting the experiment

collecting the data and exporting the data for analysis it was determined

that Steel has the largest Young’s Modulus followed by %rass and "#$S

$lastic respectively. #n regards to yield strength from highest to lowest it is

%rass Steel and "#$S $lastic. %rea!ing strength calculations returned the

same phenomenon as yield strength. )hen considering ductility *'

&longation+ Steel possessed the highest value followed by "#$S $lastic and

%rass respectively.

Introduction

The Tensile Test is well established experiment to measure several

properties of a material. They are such properties such as yield strength

tensile strength elastic properties and ductility. The results of such as test is


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had succumbed to the stress applied it was necessary to evaluate the

change in length and cross sectional area two values calculated by the

software. (fter the experiment analysis and conclusions could be drawn

about the behavior of the materials under tension.

Data

The following data show the measured dimensions of the coupons

using a caliper. These values will become necessary later when determining

factors such as elongation and ductility.

Sampl

e

"#$S

$lastic

2

"#$S

$lastic

3

%rass

2

%rass

3

%rass

4

Steel 2 Steel 3 Steel 4

5ength

*mm+

67.38 67.44 9:.66 9:.6; 9:.:8 67.72 67.7: 67.76

)idth

*mm+

8.78 8.7; 8.7 8.7 4.:6 8.72 8.73 8.7

"eight

*mm+

7.8 7.8 7.76 7.76 7.76 7.7: 7.7: 2.7


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The following data show the stress strain curve created from each trial of

each sample.

7.77&=77 2.77&-72 3.77&-72 4.77&-72 8.77&-727.77&=77

.77&=77

2.77&=72

2. 7&=72

3.77&=72

3. 7&=72

4.77&=72

4. 7&=72

f*x+ >?@ > 7 Tensile Test: Plastic Trial 1

5inear *+

Strain (mm/mm)

Stress(MPa)

Figure 1 HIPS Plastic Trial 1


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7.77&=77 .77&-73 2.77&-72 2. 7&-727.77&=77

.77&=77

2.77&=72

2. 7&=72

3.77&=72

3. 7&=72

4.77&=72

4. 7&=72

f*x+ >?@ > 7 Tensile Test: Plastic Trial

5inear *+

Strain (mm/mm)

Stress(MPa)

Figure HIPS Plastic Trial

7.77&=77 2.77&-73 3.77&-73 4.77&-737.77&=77

.77&=72

2.77&=73

2. 7&=73

3.77&=73

3. 7&=73

f*x+ >?@ > 7 Tensile Test: !rass Trial 1

5inear *+

Strain (mm/mm)

Stress (MPa)

Figure " !rass Trial 1


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7.77&=77 2.77&-72 3.77&-72 4.77&-727.77&=77

.77&=72

2.77&=73

2. 7&=73

3.77&=73

3. 7&=73

f*x+ >?@ > 7 Tensile Test: Steel Trial 1

5inear *+

Strain (mm/mm)

Stress (MPa)

Figure % Steel Trial 1

7.77&=77 3.77&-72 8.77&-727.77&=77

.77&=72

2.77&=73

2. 7&=73

3.77&=73

f*x+ >?@ > 7 Tensile Test: Steel Trial

5inear *+

Strain (mm/mm)

Stress (MPa)

Figure & Steel Trial


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#t should be noted that the Young’s Modulus was ta!en directly from

the calculated slopes of the Stress-Strain graphs created in &xcel. Therefore

there are no calculations performed. "owever the values were averaged

together before being entered into Table #.


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0.2 x MaximumStrainValue = Yield Strenth

0.2 x0.300581 (mmmm)= 0.602 (mm/mm)

From the new strain rate of 7.;73 *mmBmm+ a new trendline can be

drawn parallel to the elastic region. The new line intersects the Stress-Strain

curve at 34.4 M$a.

,uctility will also be computed using data from the stress strain curve.

,uctility is the measure of how much stress a material can withstand once it

has reached plastic deformation. Since ductility can be calculated using

length elongation the measurements for "#$S $lastic %rass and Steel are

37.33' 27.8;' and 47.34' respectively. The previous values were

computed using the following eCuation.


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%rea!ing strength was also a value ta!en directly from the graph so no

calculations were needed. "owever the values were averaged together

before being entered into Table ##.


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Strength. This is not surprising when comparing the strength capabilities of

plastic to metals.


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#n conclusion it should be noted that the tensile test is a very eDective

means of material properties analysis. The experiment was conducted and

data was collected concerning the Young’s Modulus yield strength ductility

and brea!ing strength of three types of materials. &ach material was tested

three times to satisfy scienti1c criteria of accuracy of the results. Several

conclusions could be drawn about the behavior of the materials under stress

some being counter intuitive.

Richard Garrison Material Science Lab 1

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