chapter 5 results and discussions -...

83

CHAPTER 5

RESULTS AND DISCUSSIONS

5.1 Determination of Volume Fraction. 84

5.2 Tension Test. 86

5.3 Flexural Test. 90

5.4 Inter laminar Shear Test. 177

5.5 Failure Analysis. 208

5.6 Finite Element Analysis. 210

84

CHAPTER 5

RESULTS AND DISCUSSIONS

5.1: DETERMINATION OF VOLUME FRACTION:

Material Fibre (%) Epoxy Resin (%)

FRP (Glass Fibre Reinforced Polymer)

58 (Glass)

42

FRP (Graphite Fibre Reinforced polymer)

56 (Graphite)

44

FRP (Carbon Fibre Reinforced Polymer)

54 (Carbon)

46

Table 5.1 shows the volume fraction for the three types of specimens prepared,

glass Fibre reinforced polymer, graphite Fibre reinforced polymer and carbon

reinforced polymer. It is observed that the Fibre content in case of the glass Fibre

reinforced polymer accounts to 58% and resin 42%,in graphite Fibre reinforcement

fibber content accounts to 56%and 44% resin, carbon Fibre reinforced laminates has

54% Fibre and 46% resin. The volume fraction is determined by the weight ratio

method. The determination of volume fraction is a important criteria which will have

a great influence on the mechanical properties of the specimens. Table 5.2 shows the

density for the three different fibres that were used for the manufacture of the

laminates.

Material-Fibre Density, g/cm3

E-Glass 2.54 Graphite 1.95 Carbon 1.75

Table 5.2: Showing the Density of Glass, Graphite &Carbon Fibre

Table 5.1: Showing the Percentage of Glass, Graphite, Carbon Fibre

85

Figure 5.1, 5.2 and 5.3 shows the percentage of fibre content and resin in the

three different laminates. It is evident from the pie charts that the glass fibre laminates

have the highest percentage of fibres when compared with the other two varieties of

the laminates. The percentage variation of the fibre contents attributes to the variation

in the density of the three different fibres system used in the manufacture of the

laminates. The weight ratio is a standard simple method used for the determination of

the volume fraction, in this method the fibres are weighed before the preparation of

the laminates and the final weight of the laminate is determined by knowing the

density of the materials the volume fraction of the laminates are determined.

58%42%

% Content of Glass Fiber & Epoxy Resin

Glass FiberEpoxy Resin

56%44%

% Content of Graphite Fibre & Epoxy Resin

Graphite FibreEpoxy Resin

54%46%

% Content of Carbon Fibre & Epoxy Resin

Carbon FiberEpoxy Resin

Figure 5.1: Graph showing the % content of Glass Fibre and Epoxy Resin.

Figure 5.2: Graph showing the % content of Graphite Fibre and Epoxy Resin.

Figure 5.3: Graph showing the % content of Graphite Fibre and Epoxy Resin.

86

5.2 TENSION TEST ASTM-3039.

Figure 5.4: Graph - Load Vs Displacement –Glass Fibre

Figure 5.4: Graph - Load Vs Displacement –Graphite fibre

87

Material Ultimate Tensile

strength M Pa

% of

Elongation

FRP 00/900(Glass fibre) 346 4.6

FRP 00/900(Graphite Fibre) 535 2.9

FRP 00/900(Carbon Fibre) 660 1.7

Specimen graph of load Vs deflection is shown above and the table provides

the ultimate tensile strength for different specimens. The graph shows a linear

behaviour till the yield point and falls suddenly at the yield point indicating the

material yielding and material loosing its ability to with stand any more load.

Table 5.3: Average values of Ultimate Tensile Strength and % Elongation

Figure 5.4: Graph - Load Vs Displacement –Carbon fibre

88

The tension test reveals the tensile strength and the % elongation of the specimens

that are subjected to the test. The graph of the tension test Vs specimen designation

and the graph of the % elongation and the specimen designation are plotted.

0

100

200

300

400

500

600

700

Glass Fibre Graphite Fiber Carbon Fibre

Tensile Strength

346

535660

Tens

ile S

treng

th N

/mm

2

00.5

11.5

22.5

33.5

44.5

5

Glass Fibre Reinforced polymer

Graphite Fibre Reinforced Polymer

Carbon Fibre Reinforced Polymer

% E

long

atio

n

% Elongation -Fiber Type

4.6

2.91.7

Figure 5.5: Graph showing tensile strength Vs type of fibre reinforcement

Figure 5.6: Graph -% Elongation Vs type of specimen for 2mm thick specimen.

89

As a preliminary method of investigation, the tension test is conducted on the

three types of the specimens that is, glass, graphite and carbon reinforced laminates.

The basic desired mechanical property like the tensile strength and % elongation of

the specimen is evaluated by performing the tension test on the three different types of

the laminates for 2mm thick specimens. Table 5.3 shows the ultimate tensile strength

and % elongation for glass fibre reinforced laminates, graphite fibre reinforced

laminate and carbon fibre reinforced laminate. The carbon fibre reinforced laminates

show greater strength [660 N/mm2] when compared with graphite and glass fibre

reinforced laminates. The graphite fibre reinforced laminates exhibit more strength

[535 N/mm2] than glass fibre reinforced laminates, but has a lesser strength compared

with the carbon fibre reinforced laminates. Glass fibre reinforced laminates shows a

moderate strength [346 N/mm2] under tension strength but satisfies the required value

of strength requirement for the mechanical applications that can be used for the sheet

moulded components. The different strength values are attributed to their basic

properties of the reinforcement materials. Glass fibre reinforced specimen exhibits

more elongation than the graphite and carbon reinforced laminates. Figure 5.4 shows

the typical load versus displacement curve under tension test. Figure 5.5 shows the

graph of tensile strength versus fibre reinforcement. Figure 5.6 shows the graph of %

elongation versus type of fibre reinforcement from the graph it is clearly evident that

the glass fibre reinforced laminate has a high elastic property[4.6%] than compared

with the graphite[2.9%] and carbon fibre reinforced laminates[1.7%]. The percentage

of elongation of carbon reinforced laminates has a low value when compared with

graphite and glass where as carbon fibre reinforced laminates exhibits high strength

under tension test.

90

5.3 FLEXURAL TEST

Table -5.4: Details of specimen for flexural test.

Plain weave bi-woven glass fibre, Plain weave bi-woven graphite fibre and

plain weave bi woven carbon fibre having 0.28-0.3 mm thickness is used as the

reinforcement material with two different fibre orientations 00/450& 00/900 along with

the resin as matrix material to prepare the fibre reinforced laminate of two different

thickness 2mm & 4mm size specimens, which resulted in twelve different varieties of

specimens, these specimens were subjected to flexural tests. To prepare a 2mm

specimen it is required to pile up 7 layers of plain weave bi-woven fabric and to

prepare 4mm thick specimen 14 layers of bi-woven fabrics are used. Table 5.4 shows

the details of specimens that are subjected to the flexural tests.

SPECIMEN TYPE

FIBRE ORIENTATION

THICKNESS

Plain weave bi-Woven Glass

Fibre Reinforced Polymer

00/450

2mm

4mm

00/900

2mm

4mm

Plain weave bi-Woven

Graphite Fibre Reinforced

Polymer

00/450

2mm

4mm

00/900

2mm

4mm

Plain weave bi-Woven

Carbon Fibre Reinforced

Polymer

00/450

2mm

4mm

00/900

2mm

4mm

91

Table- 5.5: Specimen designation for different types of specimens (A1-A18)

The above table shows the designation for various specimens from A1 to A18,

the designation of the specimen is obtained in order to identify the specimen easily.

The designations derived are the abbreviated names for the individual specimens.

SAMPLE.

Sample Designation

SAMPLE TYPE

FIBRE ORIENTATION

THICKNESS

GL2 S-1 /900

A1 GLASS FIBRE

00/900

2mm

GL2 S-2/900 A2

GL2 S-3/900 A3

GL4 S-1 /900

A4 GLASS FIBRE

00/900

4mm

GL4 S-2/900 A5

GL4 S-3/900 A6

GL2 S-1 /450

A7 GLASS FIBRE

00/450

2mm

GL2 S-2/450

A8

GL2 S-3/450 A9

GL4 S-1 /450

A10 GLASS FIBRE

00/450

4mm

GL4 S-2/450

A11

GL4 S-3/450 A12

GR2 S-1/450 A13

GRAPHITE FIBRE

00/450

2mm

GR2 S-2/450 A14

GR2 S-3/450 A15

GR4 S-1/450 A16 GRAPHITE

FIBRE

00/450

4mm

GR4 S-2/450 A17

GR4 S-3/450 A18

92

Table-5.6: Specimen designation for different types of specimens (A19-A36).

The above table shows the designation for various specimens from A1 to A18,

the designation of the specimen is drawn in order to identify the specimen easily. The

designations derived are the abbreviated names for the individual specimens.

SAMPLE.

Sample Designation

SAMPLE TYPE

FIBRE ORIENTATION

THICKNESS

GR2 S-1/900 A19

GRAPHITE FIBRE

00/900

2mm GR2 S-2/900 A20

GR2 S-3/900 A21

GR4 S-1/900 A22

GRAPHITE FIBRE

00/900

4mm GR4 S-2/900 A23

GR4 S-3/900 A24

CA2S-1/900 A25 CARBON

FIBRE

0/900 2mm CA2S-2/900 A26

CA2S-3/900 A27


FIBRE

0/900 4mm CA4S-2/900 A29

CA4S-3/900 A30


FIBRE

00/450 2mm CA2S-2/450 A32

CA2S-3/450 A33


FIBRE

00/450 4mm CA4S-2/450 A35

CA4S-3/450 A36

93

Table- 5.7: Specimen designation and average thickness of the specimens measured (A1-A18).

Table shows the average thickness of the specimen, the thickness is measured

at three different positions along the length of the specimen and the average value is

found out for each specimen. In the above table the average thickness of specimen’s

from A1-A18 is listed. It was fond that the thickness is varied marginally along the

length hence the average length is taken.

SPECIMEN ID-

ILSS

SPECIMEN

DESIGNATION

Thickness Average

Thickness

mm

Trial

1

Trial

2

Trial

3

GL2 S-1 /900 A1 1.92 1.90 1.94 1.92

GL2 S-2/900 A2 2.00 2.13 2.05 2.06

GL2 S-3/900 A3 1.96 1.95 1.98 1.96

GL4 S-1 /900 A4 3.94 3.97 3.95 3.95

GL4 S-2/900 A5 3.99 3.98 3.95 3.97

GL4 S-3/900 A6 3.96 3.95 3.98 3.96

GL2 S-1/450 A7 2.02 2.02 1.99 2.01

GL2 S-2/450 A8 2.05 2.23 2.15 2.14

GL2 S-3/450 A9 1.91 1.93 1.99 1.94

GL4 S-1/450 A10 3.89 3.87 3.85 3.87

GL4 S-2/450 A11 3.97 3.77 3.83 3.85

GL4 S-3/450 A12 3.73 3.66 3.78 3.72

GR2 S-1/450 A13 2.22 2.12 1.99 2.11

GR2 S-2/450 A14 2.15 2.03 2.15 2.11

GR2 S-3/450 A15 2.11 2.03 2.09 2.07

GR4 S-1/450 A16 3.98 4.07 4.15 4.06

GR4 S-2/450 A17 4.17 4.13 3.93 4.07

GR4 S-3/450 A18 4.16 3.96 3.98 4.03

94

Table - 5.8: Specimen designation and average thickness of the specimens

(A19 - A36).

Table shows the average thickness of the specimen, the thickness is measured

at three different positions along the length of the specimen and the average value is

found out for each specimen. In the above table the average thickness of specimen’s

from A19-A36 is listed.

SPECIMEN ID-ILSS

SPECIMEN DESIGNATION

Thickness Average Thickness

mm Trial

1 Trial

2 Trial

3

GR2 S-1/900 A19 1.92 1.90 1.94 1.92

GR2 S-2/900 A20 2.00 2.13 2.05 2.06

GR2 S-3/900 A21 1.96 1.95 1.98 1.96

GR4 S-1/900 A22 3.98 4.07 4.15 4.06

GR4 S-2/900 A23 4.17 4.13 3.93 4.07

GR4 S-3/900 A24 4.16 3.96 3.98 4.03

CA2S-1/900 A25 2.02 2.02 1.99 2.01

CA2S-2/900 A26 2.05 2.23 2.15 2.14

CA2S-3/900 A27 1.91 1.93 1.99 1.94

CA4S-1/900 A28 3.94 3.97 3.95 3.95

CA4S-2/900 A29 3.99 3.98 3.95 3.97

CA4S-3/900 A30 3.96 3.95 3.98 3.96

CA2S-1/450 A31 2.22 2.12 1.99 2.11

CA2S-2/450 A32 2.15 2.03 2.15 2.09

CA2S-3/450 A33 2.11 2.03 2.09 2.07

CA4S-1/450 A34 3.98 4.07 4.15 4.06

CA4S-2/450 A35 4.17 4.13 3.93 4.07

CA4S-3/450 A36 4.16 3.96 3.98 4.03

95

Table -5.9 : Specimen designation and average width of the specimens (A1-A18).

Table shows the average width of the specimen, the width is measured at three

different positions along the length of the specimen and the average value is found out

for each specimen. In the above table the average thickness of specimen’s from

A1-A18 is as shown.

SPECIMEN ID-ILSS

SPECIMEN

DESIGNATION

Width, mm Average

Width mm

Span Length Length

Trial 1

Trial

2

Trial

3 GL2 S-1 /900 A1 12.64 12.56 12.39 12.53 31

150 GL2 S-2/900 A2 12.59 12.43 12.41 12.46 32

GL2 S-3/900 A3 12.65 12.46 12.44 12.48 32

GL4 S-1 /900 A4 12.66 12.56 12.39 12.53 50

150 GL4 S-2/900 A5 12.55 12.43 12.41 12.46 48

GL4 S-3/900 A6 12.65 12.46 12.44 12.51 51

GL2 S-1/450 A7 12.51 12.43 12.41 12.46 32

150 GL2 S-2/450 A8 12.75 12.16 12.44 12.45 33

GL2 S-3/450 A9 12.68 12.45 12.46 12.53 34

GL4 S-1/450 A10 12.55 12.49 12.46 12.5 62

150 GL4 S-2/450 A11 12.45 12.36 12.54 12.45 62

GL4 S-3/450 A12 12.48 12.55 12.56 12.53 61

GR2 S-1/450 A13 12.59 12.53 12.61 12.57 34

150 GR2 S-2/450 A14 12.65 12.46 12.64 12.58 34

GR2 S-3/450 A15 12.68 12.65 12.46 12.58 34

GR4 S-1/450 A16 12.61 12.59 12.61 12.60 65

150 GR4 S-2/450 A17 12.65 12.46 12.64 12.58 65

GR4 S-3/450 A18 12.68 12.65 12.46 12.59 65

96

Table - 5.10: Specimen designation and average width of the specimens

(A19 - A36).

The table above shows the average width of the specimen from A19 to A36.

SPECIMEN ID-ILSS

SPECIMEN

DESIGNATIO

N

Width, mm

Average Width

mm

Span Length Length

Trial 1

Trial

2

Trial

3

GR2 S-1/900 A19 12.59 12.53 12.61 12.57 34

150 GR2 S-2/900 A20 12.65 12.46 12.64 12.58 33

GR2 S-3/900 A21 12.68 12.65 12.46 12.59 34

GR4 S-1/900 A22 12.64 12.56 12.39 12.50 66

150 GR4 S-2/900 A23 12.59 12.43 12.41 12.47 65

GR4 S-3/900 A24 12.65 12.46 12.44 12.51 66

CA2S-1/900 A25 12.61 12.59 12.61 12.60 34

150 CA2S-2/900 A26 12.65 12.46 12.64 12.58 35

CA2S-3/900 A27 12.68 12.65 12.46 12.59 35

CA4S-1/900 A28 12.75 12.16 12.44 12.45 66

150 CA4S-2/900 A29 12.65 12.46 12.64 12.58 66

CA4S-3/900 A30 12.45 12.36 12.54 12.45 65

CA2S-1/450 A31 12.59 12.53 12.61 12.57 34

150 CA2S-2/450 A32 12.65 12.46 12.64 12.58 33

CA2S-3/450 A33 12.68 12.65 12.46 12.59 34

CA4S-1/450 A34 12.66 12.56 12.39 12.53 66

150 CA4S-2/450 A35 12.45 12.36 12.54 12.45 65

CA4S-3/450 A36 12.59 12.43 12.41 12.47 66

97

TABLE- 5.11: Table showing Load Vs Displacement Diagram A1.

Specimen Designation : A1 GL2-S1/900

P- Load N. P- 427 N. h- Depth mm. h-1.92 mm. L-Span Length mm L-61.44 mm.

Flexural Strength

N/mm2 (M Pa)

Flexural Stiffness N/mm

Maximum Load (Pmax)

N

Deflection. At. Pmax

mm

Max. Deflection.

mm 253 170.8 427.000 2.5 4.56

The table above shows the details of load deflection diagram for specimen A1.

From the diagram it can be observed that the yielding takes place at a load of 427.0 N.

The flexural strength is 253 N/mm2. The graph shows a sudden fall after the yield

point indicating the degradation in the strength of the laminated composite.

Flexural Strength= 3/2*(PL/bh2), =1.5*(510x39.56/13.31x2.162) = 425.75 Mpa.

Flexural Modulus=Stress/Strain, [from the graph] Ex: 40/2 =20

i.e, Slope of the stress strain curve with in the Elastic range.

Stiffness = Load/deflection [From the graph]. (Maximum load / Maximum deflection).

98

TABLE- 5.12: Table Showing Stress Vs Strain Diagram A1.


P- Load N. P-427 N. h- Depth mm. h-1.92 mm. L-Span Length mm L-61.44 mm.

FLEXURAL STRENGTH

M Pa

FLEXURAL MODULUS

M Pa

MAXIMUM STRESS

M Pa

MAXIMUM STRAIN

In % 253 20 180 10

Table shows the stress strain diagram for specimen A1. The maximum stress is found

to be180 MPa. From the graph it is clear that after the yield point the strain rate

increases indicating that the specimen can not with stand further loading any more.

99

TABLE- 5.13: Table Showing Load Vs Displacement Diagram A2.


From the diagram it can be observed that the yielding takes place at a load of 492.0 N.

The flexural strength is 310 N/mm2. The graph shows a sudden fall after the yield

point indicating the laminate not able to with stand further loading.



Flexural Strength

N/mm2 (M Pa)


Maximum Load (Pmax)

N


mm

Max. Deflection.

mm 310 182.4 492.000 2.790 5.660

100




FLEXURAL STRENGTH

M Pa

FLEXURAL MODULUS

M Pa

MAXIMUM STRESS

M Pa

MAXIMUM STRAIN

In % 310 20 210 10 %.

Table shows the stress strain diagram for specimen A2. The flexural modulus

was found to be 20 MPa. The maximum stress was found to be 210 MPa. From the

graph it is clear that after the yield point the strain rate increases indicating the

specimen not able to with stand load after the yielding.

101

TABLE-5.15: Table Showing Load Vs Displacement Diagram A3.



Flexural Strength

N/mm2 (M Pa)


Maximum Load (Pmax)

N


mm

Max. Deflection. mm

251 176.9 468 2.6 4.6


From the diagram it can be observed that the yielding takes place at a load of 468 N.

The flexural strength is 251 N/mm2. The graph shows linearity till the yield point and

there is a sudden fall in the load after the yield point, there is an increase in

deformation even with the decrease in the load, after the yield point.

102

TABLE-5.16: Table Showing Stress Vs Strain Diagram A3.



FLEXURAL STRENGTH

M Pa

FLEXURAL MODULUS

N/mm2

MAXIMUM STRESS

M Pa

MAXIMUM STRAIN

In %. 251 20 180 10

The maximum stress is 180 MPa and the recorded maximum strain is 10%.

The graph exhibits linearity till the maximum stress is attained and it can be observed

that there is an increase in %strain after the linear range.

103



P- Load N. P- 610.50 N. h- Depth mm. h- 3.95mm. L-Span Length mm L-126.4 mm.

Flexural Strength

N/mm2 (M Pa)


Maximum Load (Pmax)

N


mm

Max. Deflection. mm

438 226.11 610.50 2.7 5.00

The maximum load the specimen A4 can with stand is 610.50 N, the yield

point is attained at this load and the material shows linearity till the yield point. At the

yield point the load falls suddenly indicating the material loosing its strength. Further

loading of the specimen leads to increase of displacement at lower loads.

104


Specimen Designation : A4 GL4-S1-/900


FLEXURAL STRENGTH

M Pa

FLEXURAL MODULUS

N/mm2

MAXIMUM STRESS

M Pa

MAXIMUM STRAIN

In %.

438 30 258 11

Table5.18, shows the stress strain diagram for specimen A4, the maximum

stress is 258 MPa, the maximum strain rate is 11% the flexural modulus is 30 and the

flexural strength is 438 Mpa. The span length of the specimen is 126.8mm, the

thickness of the specimen is 3.95 mm and the maximum load the specimen can with

stand is 610.5N.

105



P- Load N. P-612.25 N. h- Depth mm. h-3.97 mm. L-Span Length mm L-127.04 mm

Flexural Strength

N/mm2 (M Pa)


Maximum Load (Pmax)

N


mm

Max. Deflection.

mm 439 206.03 612.25 2.97 5.45


From the diagram it can be observed that the yielding takes place at a load of 612.25

N. The flexural strength is 439 N/mm2. The graph shows linearity till the yield point

and there is a sudden fall in the load after the yield point, there is an increase in


106




FLEXURAL STRENGTH

M Pa

FLEXURAL MODULUS

M Pa

MAXIMUM STRESS

M Pa

MAXIMUM STRAIN

In % 439 30 260 12





stand is 612.25N.

107



P- Load N. P-611.37 N. h- Depth mm. h-3.96 mm. L-Span Length mm L- 126.72 mm

Flexural Strength

N/mm2 (M Pa)


Maximum Load (Pmax)

N


mm

Max. Deflection.

mm 448 216.03 611.37 2.83 5.45






108

TABLE -5.22: Table Showing Stress Vs Strain Diagram A6.

Specimen Designation : A6 GL4-S1-0-900

P- Load N. P-611.37 N. h- Depth mm. h-3.96 mm. L-Span Length mm L-126.72 mm.

FLEXURAL STRENGTH

M Pa

FLEXURAL MODULUS

M Pa

MAXIMUM STRESS

M Pa

MAXIMUM STRAIN

In % 448 30 260 11





stand is 611.37N.

109

TABLE -5.23: Table Showing Load Vs Displacement Diagram A7.


P- Load N. P- 445.25 N. h- Depth mm. h-2.01 mm. L-Span Length mm L-64.32 mm.

Flexural Strength

N/mm2 (M Pa)


Maximum Load (Pmax)

N


mm

Max. Deflecti

on. mm

421 188.66 445.25 2.36 6.9






110




FLEXURAL STRENGTH

M Pa

FLEXURAL MODULUS

M Pa

MAXIMUM STRESS

M Pa

MAXIMUM STRAIN

In % 421 200 1180.000 13.700


stress is 1180 MPa, the maximum strain rate is 13.7% the flexural modulus is 200 and

the flexural strength is 421 Mpa. The span length of the specimen is 64.32mm, the


stand is 445.25N.

111


Specimen Designation : : A8 GL2-S2/450


Flexural Strength

N/mm2 (M Pa)


Maximum Load (Pmax)

N


mm

Max. Deflection.

mm 389 235.25 418.750 1.780 6.010






112




FLEXURAL STRENGTH

M Pa

FLEXURAL MODULUS

M Pa

MAXIMUM STRESS

M Pa

MAXIMUM STRAIN

IN % 389 200 1150.000 12.000


stress is 1150 MPa, the maximum strain rate is 12% the flexural modulus is 200 and



stand is 418.75N.

113




Flexural Strength

N/mm2 (M Pa)


Maximum Load (Pmax)

N


mm

Max. Deflection.

mm 417 190.55 428.750 2.250 6.280






114

TABLE -5.28: Table showing stress Vs strain Diagram A9.



FLEXURAL STRENGTH

M Pa

FLEXURAL MODULUS

M Pa

MAXIMUM STRESS

M Pa

MAXIMUM STRAIN

IN % 417 200 1160.000 12.500 %





stand is 428.75N.

115




Flexural Strength

N/mm2 (M Pa)


Maximum Load (Pmax)

N


mm

Max. Deflection. mm

466.07

225

810

3.6

8.3

The table above shows the details of load deflection diagram for specimen

A10. From the diagram it can be observed that the yielding takes place at a load of

810 N. The flexural strength is 466.07 N/mm2. The graph shows linearity till the yield

point and there is a sudden fall in the load after the yield point, there is an increase in


116



P- Load N. P- 810 N. h- Depth mm. h-3.87 mm. L-Span Length mm L-123.84 mm

FLEXURAL STRENGTH

M Pa

FLEXURAL MODULUS

M Pa

MAXIMUM STRESS

M Pa

MAXIMUM STRAIN

IN %

466.07 250 1400 16



the flexural strength is 466.07 Mpa. The span length of the specimen is 123.84 mm,

the thickness of the specimen is 3.87 mm and the maximum load the specimen can

with stand is 810N.

117



P- Load N. P- 820 N. h-Depth mm. h-3.85 mm. L-Span Length mm L-123.2 mm.

Flexural Strength

N/mm2 (M Pa)


Maximum Load (Pmax)

N


mm

Max. Deflection.

mm 464.86 215.7 820 3.8 9.6






118




FLEXURAL STRENGTH

M Pa

FLEXURAL MODULUS

M Pa

MAXIMUM STRESS

M Pa

MAXIMUM STRAIN

IN % 464.86 240 1400.000 18.000%



the flexural strength is 464.86 Mpa. The span length of the specimen is 123.2mm, the


stand is 820N.

119




Flexural Strength

N/mm2 (M Pa)


Maximum Load (Pmax)

N


mm

Max. Deflection.

mm 468.60 242.4 800 3.3 9.000






120


Specimen Designation : : A12 GL4-S3/450


FLEXURAL STRENGTH

M Pa

FLEXURAL MODULUS

M Pa

MAXIMUM STRESS

M Pa

MAXIMUM STRAIN

IN % 468.60 200 1785.000 18.000


stress is1785 MPa, the maximum strain rate is 18% the flexural modulus is 200 and

the flexural strength is 468.6 Mpa. The span length of the specimen is 119.04mm, the


stand is 800N.

121


Specimen Designation : A13 GR2-S1/450

P- Load N. P- 465 N. h- Depth mm. h- 2.11mm. L-Span Length mm L-67.52 mm.

Flexural Strength

N/mm2 (M Pa)


Maximum Load (Pmax)

N


mm

Max. Deflection.

mm 465 237.10 455.250 1.920 5.140



455.25 N. The flexural strength is 465 N/mm2. The graph shows linearity till the yield



122




FLEXURAL STRENGTH

M Pa

FLEXURAL MODULUS

M Pa

MAXIMUM STRESS

M Pa

MAXIMUM STRAIN

IN % 465 500 1195 10.20





stand is 455.25N.

123




Flexural Strength

N/mm2 (M Pa)


Maximum Load (Pmax)

N


mm

Max. Deflection

mm 466 215.05 421.500 1.960 9.770






124


Specimen Designation : : A14 GR2-S2/450


FLEXURAL STRENGTH

M Pa

FLEXURAL MODULUS

M Pa

MAXIMUM STRESS

M Pa

MAXIMUM STRAIN

IN % 466 550 1250 19.800



the flexural strength is 466 Mpa. The span length of the specimen is 67.5 mm, the


stand is 421N.

125




Flexural Strength

N/mm2 (M Pa)


Maximum Load (Pmax)

N


mm

Max. Deflection.

mm 465 226 437.9 1.930 5.140






126



P- Load N. P- 437.90 N. h- Depth mm. h-2.07mm. L-Span Length mm L-66.24 mm.

FLEXURAL STRENGTH

M Pa

FLEXURAL MODULUS

M Pa

MAXIMUM STRESS

M Pa

MAXIMUM STRAIN

IN % 465 490 1195 10.20





stand is 437.9N.

127



P- Load N. P-664.5 N. h- Depth mm. h- 4.06mm. L-Span Length mm L-129.92 mm.

Flexural Strength

N/mm2 (M Pa)


Maximum Load (Pmax)

N


mm

Max. Deflection.

mm 480 254.59 664.50 2.61 6.530






128



P- Load N. P- 664.50 N. h- Depth mm. h-4.06mm. L-Span Length mm L-129.92mm.

FLEXURAL STRENGTH

M Pa

FLEXURAL MODULUS

M Pa

MAXIMUM STRESS

M Pa

MAXIMUM STRAIN

IN % 480 340 1770.00 13.000



the flexural strength is 480Mpa. The span length of the specimen is 129.92mm, the


stand is 664.5N.

129


Specimen Designation : Designation : A17 GR4-S2/450


Flexural Strength

N/mm2 (M Pa)


Maximum Load (Pmax)

N


mm

Max. Deflection.

mm

487

250.08

712.75

2.85

6.390






130




FLEXURAL STRENGTH

M Pa

FLEXURAL MODULUS

M Pa

Maximum Stress M Pa

Maximum Strain In %

487 360 1800.00 13.000





stand is 712N.

131




Flexural Strength

N/mm2 (M Pa)


Maximum Load (Pmax)

N


mm

Max. Deflection.

mm 484 252.03 680.50 2.70 6.530






132


Specimen Designation : : A18 GR4-S1/450


FLEXURAL STRENGTH

M Pa

FLEXURAL MODULUS

M Pa

MAXIMUM STRESS

M Pa

MAXIMUM STRAIN

In % 484 340 1770.00 13.000





stand is 680.5N.

133




Flexural Strength

N/mm2 (M Pa)


Maximum Load (Pmax)

N


mm

Max. Deflection.

mm 325 205.63 432.250 2.102 4.380






134




FLEXURAL STRENGTH

M Pa

FLEXURAL MODULUS

M Pa

MAXIMUM STRESS

M Pa

MAXIMUM STRAIN In %

325 460 1100 9.00





stand is 432N.

135




Flexural Strength

N/mm2 (M Pa)


Maximum Load (Pmax)

N


mm

Max. Deflection.

mm 343 203.86 422.000 2.070 6.370



422 N. The flexural strength is 343 N/mm2. The graph shows linearity till the yield



136




FLEXURAL STRENGTH

M Pa

FLEXURAL MODULUS

M Pa

MAXIMUM STRESS

M Pa

MAXIMUM STRAIN

In % 343 460 1100.00 13.000





stand is 422.0N.

137




Flexural Strength N/mm2 (M Pa)


Maximum Load (Pmax) N

Deflection. At. Pmax mm

Max. Deflection. mm

328 196.36 432.20 2.201 4.500






138




FLEXURAL STRENGTH

M Pa

FLEXURAL MODULUS

M Pa

MAXIMUM STRESS

M Pa

MAXIMUM STRAIN

In % 328 450 1100 8.800





stand is 432N.

139



P- Load N. P-716.5 N. h- Depth mm. h-3.95mm. L-Span Length mm L-126.4 mm.

Flexural Strength

N/mm2 (M Pa)


Maximum Load (Pmax)

N


mm

Max. Deflection.

mm 464 230.38 716.500 3.110 7.270






140




FLEXURAL STRENGTH M Pa

FLEXURAL MODULUS M Pa

Maximum Stress M Pa

Maximum Strain In %

464 620 1890.00 15.00





stand is 716.5N.

141



P- Load N. P-710.5 N. h- Depth mm. h-3.97mm. L-Span Length mm L-127.04 mm.

Flexural Strength

N/mm2 (M Pa)


Maximum Load (Pmax)

N


mm

Max. Deflection.

mm 466 236.04 710.5 3.01 6.970






142



P- Load N. P-710.5 Span h- Depth mm. h-3.97mm. L-Span Length mm L-127.04 mm.

FLEXURAL STRENGTH

M Pa

FLEXURAL MODULUS

M Pa

MAXIMUM STRESS

M Pa

MAXIMUM STRAIN

IN % 466 600 1890.000 15.000





stand is 710.5N.

143




Flexural Strength

N/mm2 (M Pa)


Maximum Load (Pmax)

N


mm

Max. Deflection.

mm 454 238.20 714.6 3.20 7.200






144




FLEXURAL STRENGTH

M Pa

FLEXURAL MODULUS

M Pa

MAXIMUM STRESS

M Pa

MAXIMUM STRAIN

IN % 454 580 1800.00 15.000





stand is 714.6N.

145


Specimen Designation : : A25 CA2-S1/900

P- Load N. P-610 N. h- Depth mm. h-2.16mm. L-Span Length mm L-69.12 mm.

Flexural Strength

N/mm2 (M Pa)


Maximum Load (Pmax)

N


mm

Max. Deflection.

mm

425.74

217.85

610

2.6

2.8






146


Specimen Designation : A26 CA2-S2/900

P- Load N. P- 680 N. h- Depth mm. h-2.17mm. L-Span Length mm L-69.44 mm.

Flexural Strength

N/mm2 (M Pa)


Maximum Load (Pmax)

N


mm

Max. Deflection.

mm 445.74 225.16 680 3 3.12






147




Flexural Strength

N/mm2 (M Pa)


Maximum Load (Pmax)

N


mm

Max. Deflection.

mm 430.03 227.5 660 2.9 3.0






148



P- Load N. P-995 N. h- Depth mm. h-3.21 mm. L-Span Length mm L- 102.72mm.

Flexural Strength

N/mm2 (M Pa)


Maximum Load (Pmax)

N


mm

Max. Deflecti

on. mm

507.05 399.5 995 2.4 2.5






149




Flexural Strength

N/mm2 (M Pa)


Maximum Load (Pmax)

N


mm

Max. Deflection. mm

513.20 375.5 920 2.3 2.45






150




Flexural Strength

N/mm2 (M Pa)


Maximum Load (Pmax)

N


mm

Max. Deflection. mm

489.11 406.9 1050 2.39 2.58



1050 N. The flexural strength is489.11 N/mm2. The graph shows linearity till the

yield point and there is a sudden fall in the load after the yield point, there is an

increase in deformation even with the decrease in the load, after the yield point.

151




Flexural Strength

N/mm2 (M Pa)


Maximum Load (Pmax)

N


mm

Max. Deflection.

mm 501 281 750 2.55 2.7






152



P- Load N. P- 800 N. h- Depth mm. h-2.09 mm. L-Span Length mm L- 66.88 mm.

Flexural Strength N/mm2 (M Pa)


Maximum Load (Pmax) N

Deflection. At. Pmax mm

Max. Deflection. mm

503 420 820 2.4 2.9






153




Flexural Strength

N/mm2 (M Pa)


Maximum Load (Pmax)

N


mm

Max. Deflection.

mm 506 278 760 2.3 2.8






154




Flexural Strength

N/mm2 (M Pa)


Maximum Load (Pmax)

N


mm

Max. Deflection.

mm 564 350 1300 2.37 2.47






155




Flexural Strength

N/mm2 (M Pa)


Maximum Load (Pmax)

N


mm

Max. Deflection.

mm 562 348 1220 2.3 2.45






156




Flexural Strength

N/mm2 (M Pa)


Maximum Load (Pmax)

N


mm

Max. Deflection. mm

560 342 1400 2.3 2.45






157

TABLE-5.71: Table Showing Flexural Strength, Stiffness & Modulus for specimen A1, A2 & A3.

TABLE-5.72: Table Showing Flexural Strength, Stiffness & Modulus for

specimen A4, A5, & A6.

Test Specimen

Designation

Glass 4 mm, Orientation 00/900

Flexural

Strength

Flexural

Stiffness

Flexural

Modulus

Load

Pmax

Deflection

At Pmax.

N/mm2 N/mm N/mm2 N mm

Flexural

A4 438 226.11 30 610.50 2.70

A5 439 206.14 30 612.25 2,97

A6 448 216.03 30 611.37 2.83

Average 438.3 216.09 30 611.37 2.83

Test Specimen

Designation

Glass 2mm, Orientation 00/900

Flexural

Strength

Flexural

Stiffness

Flexural

Modulus

Load

Pmax

Deflection

At Pmax.


Flexural

A1 253 170.8 20 427 2.5

A2 310 182.4 30 492 2.7

A3 251 176.7 20 468 2.6

Average 267 176.7 25 468 2.6

158

Fig.5.7: Graph Showing –Flexural Strength Vs Specimen Designation A1, A2 &A3 -2mm, A4, A5 &A6-4mm

Fig.5.8: Graph Showing –Flexural Stiffness Vs Specimen Designation for specimen A1,A2, A3 2mm & A4,A5, & A6-4mm

159

TABLE-5.73: Table Showing Flexural Strength, Stiffness & Modulus for specimen A7, A8, & A9.


Test

Specimen

Designation

Glass 2mm, Orientation 00/450

Flexural

Strength

Flexural

Stiffness

Flexural

Modulus

Load

Pmax

Deflection

At Pmax.


Flexural

A7 421 188.66 200 445.25 2.360

A8 389 235.25 200 418.75 1.780

A9 417 190.55 200 428.75 2.250

Average 409 204.73 200 430.91 2.13

Test

Specimen

Designation

Glass 4 mm, Orientation 00/450

Flexural

Strength

Flexural

Stiffness

Flexural

Modulus

Load

Pmax

Deflection

At Pmax.


Flexural

A10 466.07 225 250 810 3.6

A11 464.86 215.7 240 820 3.8

A12 468.60 242.4 200 800 3.3

Average 466.51 227.46 230 810 3.5

160

Fig.5.9:Graph Showing –Flexural Strength Vs Specimen Designation A7, A8 &A9,A10, A11&A12

Fig.5.10: Graph Showing –Flexural Strength Vs Specimen Designation A7, A8 &A9, A10, A11&A12.

161





Test

Specimen

Designation

Graphite 4 mm, Orientation 00/450

Flexural

Strength

Flexural

Stiffness

Flexural

Modulus

Load

Pmax

Deflection

At Pmax.


Flexural

A16 480 254.59 340 664.50 2.61

A17 487 250.08 360 712.75 2.85

A18 484 252.03 340 680.50 2.70

Average 482.3 252.23 350 685.75 2.72

Test Specimen

Designation

Graphite 2mm, Orientation 00/450

Flexural

Strength

Flexural

Stiffness

Flexural

Modulus

Load

Pmax

Deflection

At Pmax.


Flexural

A13 465 237.10 500 455.25 1.92

A14 466 215.05 550 421.50 1.96

A15 465 226.89 490 437.90 1.93

Average 465.33 226.34 513.33 438.21 1.93

162

Figure-5.11: Graph Showing –Flexural Strength Vs Specimen Designation A13, A14 &A15A16, A17& A18.

Figure-5.12: Graph Showing –Flexural Stiffness Vs Specimen Designation A13, A14 &A15A16, A17& A18.

163


Test Specimen

Designation

Graphite 2 mm, Orientation 00/900

Flexural

Strength

Flexural

Stiffness

Flexural

Modulus

Load

Pmax

Deflection

At Pmax.


Flexural

A19 325 205.63 460 432.25 2.102

A20 343 203.86 460 422.00 2.070

A21 328 196.36 450 432.20 2.201

Average 332 202 470 428.75 2.124


Test Specimen

Designation

Graphite 4 mm, Orientation 00/9002 mm

Flexural

Strength

Flexural

Stiffness

Flexural

Modulus

Load

Pmax

Deflection

At Pmax.


Flexural

A22 464 230.38 620 716.5 3.11

A23 466 236.04 600 710.5 3.01

A24 454 238.20 580 714.6 3.00

Average 461.3 234.74 600 713.8 3.04

164

Fig.5.13: Graph Showing –Flexural Strength Vs Specimen Designation A19, A20 &A21 A22, A23& A24.

Fig.5.14: Graph showing the flexural stiffness Vs Specimen designation for specimen A19, A20, A21 & A22, A23 &A24.

165



Test Specimen

Designation

Carbon 4 mm, Orientation 00/900

Flexural

Strength

Flexural

Stiffness

Load

Pmax

Deflection

At Pmax.

N/mm2 N/mm N mm

Flexural

A28 507.05 399.5 995 2.49

A29 513.20 375.5 920 2.45

A30 489.11 406.9 1050 2.58

Average 503.12 393.9 988 2.50

Test Specimen

Designation

Carbon 2mm, Orientation 00/900

Flexural

Strength

Flexural

Stiffness

Load

Pmax

Deflection

At Pmax.

N/mm2 N/mm N mm

Flexural

A25 425.74 217.85 610 2.8

A26 445.74 225.16 680 3.02

A27 430.03 227.5 600 2.9

Average 433.83 223.50 650 2.9

166

Fig.5.15: Graph Showing –Flexural Strength Vs Specimen Designation A25, A26 &A27, A28, A29 &A30.

Fig.5.16:Graph Showing –Flexural Stiffness Vs Specimen Designation A25, A26 &A27,A28, A29 &A30.

167

TABLE 5.81: Table Showing Flexural Strength, Stiffness & Modulus for specimen A31, A32, & A33.

Test Specimen

Designation


Flexural

Strength

Flexural

Stiffness

Load

Pmax

Deflection

At Pmax.

N/mm2 N/mm N mm

Flexural

A31 502 279 750 2.55

A32 508 282 820 2.4

A33 504 282 760 2.3

Average 504.66 281 776 2.4


Test Specimen

Designation


Flexural

Strength

Flexural

Stiffness

Load

Pmax

Deflection

At Pmax.

N/mm2 N/mm N mm

Flexural

A34 559 345 1300 2.3

A35 565 349 1220 2.3

A36 562 351 1400 2.3

Average 562 348 1306 2.3

168

Fig.5.17: Graph Showing –Flexural Strength Vs Specimen Designation A31, A32 & A33, A34, A35 &A36.

Fig.5.18:Graph Showing –Flexural Stiffness Vs Specimen Designation A31, A32 & A33, A34, A35 &A36.

169

TABLE-5.83: Effect of thickness on flexural strength 00/900

Parameter

Fibre orientations 00/900

Glass Fibre Graphite Fibre Carbon Fibre

2mm 4mm 2mm 4mm 2mm 4mm

Flexural Strength N/mm2

267 438.3 332 461 433.8 503.1


176.7 216 202 234.7 223.5 393.9

TABLE-5.84: Effect of thickness on flexural strength 00/450

Parameter

Fibre orientations 00/450

Glass Fibre Graphite Fibre Carbon Fibre



409 466.5 465.5 482.3 504 562


204.7 227.4 226.3 252 281 348

Fig.5.19: Graph Showing the Influence of Thickness 2mm and 4mm 00/900 .

170

Fig.5.20: Graph Showing the Influence of Thickness 2mm and 4mm 00/450

TABLE-5.85: Effect of Fibre orientation for 2mm thick specimens

Parameter Glass Fibre 2mm Graphite Fibre 2mm Carbon Fibre 2mm

00/900 00/450 00/900 00/450 00/900 00/450


267 409 332 465.5 433 504


176.7 204.7 202 226.34 223.5 281

TABLE-5.86: Effect of Fibre orientation for 4mm thick specimens

Parameter Glass Fibre 4mm Graphite Fibre 4mm Carbon Fibre 4mm

00/900 00/450 00/900 00/450 00/900 00/450


438.3 466.5 461 482.3 503 562


216 227.4 234.7 252 393 348

171

Fig.5.21: Graph showing the Influence of Fibre Orientation for 2mm thick specimen

Fig.5.22: Graph showing the Influence of Fibre Orientation for 4mm thick specimen

TABLE-5.87: Influence of Fibre Type used 2mm thick

Parameter

Measured

Fibre orientation 00/900

2mm Thick


2mm Thick

Glass

Fibre

Graphite

Fibre

Carbon

Fibre

Glass

Fibre

Graphite

Fibre

Carbon

Fibre


267

332

433

409

465.5

504


176.7

202

223.5

204.7

226.3

281

172

TABLE-5.88: Influence of Fibre Type used 4mm thick

Parameter

Measured


4mm Thick


4mm Thick

Glass

Fibre

Graphite

Fibre

Carbon

Fibre

Glass

Fibre

Graphite

Fibre

Carbon

Fibre


438.2 461 503 466.5 482.3 562


216 234.7 393 227.46 252 348

Fig.5.23: Graph showing the Influence of Fibre Type used 2mm thick

Fig.5.24: Influence of Fibre Type used 4mm thick

173

The flexural test conducted shows excellent results the values shows

consistency and excellent repeatability with the different types of the specimens. The

experimentation is carried as explained in the experimentation, a simple flexural test

as per ASTM D 790 is conducted and the various flexural parameters like flexural

strength, flexural stiffness, flexural modulus, maximum load, maximum deflection are

obtained, the results are obtained using the load Vs deflection graph and also as

stress Vs strain graph. In this section a brief discussion is draw on the various aspects

of the results that are obtained. The entire analysis can be summarized as follows.

1. The effect of thickness on the flexural strength and flexural stiffness.

2. The effect of Fibre orientation on the flexural strength and flexural stiffness.

3. The effect of Fibre type on the flexural strength and stiffness are evaluated.

Flexural test conducted yields very significant results with different Fibres.

The developed experimental methodology is based on flexural tests for PMC’s has

contributed to emphasize the deformation rate effects on the overall behavior of PMC

and glass/epoxy woven laminate composites, graphite/epoxy laminate composites and

carbon/epoxy laminate composites. As the strain rate increased, noticeable effects

consist of a delayed damage onset followed by a slightly reduced damage

accumulation. Due to the inclusion of glass Fibres and epoxy resin, graphite Fibre and

epoxy resin and carbon Fibre and epoxy resin the interface strengths have increased

that can explain readily the accommodation exhibited at the macroscopic scale.

Table 5.4 represents the specimen details for the flexural test. Table 5.5&5.6

shows the specimen designation for the various types of the specimen, the specimen

designation is required in order to identify the specimen in a simple and easy manner.

174

Table 5.7 &5.8 gives the average values of the thickness of the specimens

which are required in order to determine the span length of the specimen. Table 5.9

&5.10 shows the average width of the specimens. Further table 5.11 to table 5.70,

(A1toA36) gives the load Vs deflection and stress Vs strain curves for the various

specimens. The curve clearly explains the behavior of the laminated composites the

trend remains more or less the same it can be observed that flexural strength is greater

than the tensile strength for the individual specimens. The curve remains linear till it

attains the yield point and at the yield point a drastic fall is noticed then the curve

rises again as the load is with stood by the next layer in the laminate but there will be

a decrease in load sustaining capacity and the curve falls down. The maximum load is

recorded at the yield point.

Table 5.71 to table 5.82 shows the flexural strength flexural stiffness, flexural

modulus, maximum load and maximum deformation for the different specimens

subjected to flexural test.

Table 5.83 and 5.84 along with the figures 5.17 & 5.18 shows the influence of

thickness of the specimens; it is observed that with the increase in the thickness of the

specimen there is an increase in the flexural properties like flexural strength, Flexural

stiffness, flexural modulus and maximum load with a little sacrifice in the weight of

the specimen. Fig.5.17 shows the influence of thickness of the specimens it is clearly

observed that with increase in thickness there is a drastic increase in the strength of

the material which is depicted in the graph shown. Similarly fig 5.18 shows the graph

of strength and the effect of thickness, it is clearly observed that with increase in

thickness there is an increase in stiffness. It can be observed that the both strength and

stiffness in case of 4mm thick laminated predominates. Further it is evident from the

175

graph that graphite Fibre reinforced laminates predominates over glass Fibre

reinforced laminates and carbon Fibre predominates over the graphite Fibre.

Table 5.85 and 5.86 along with the fig.5.19 and 5.20 represents the influence

of the Fibre orientation on the 2mm and 4mm thick specimens. The comparison is

drawn between the same sizes of the specimen but with different Fibre orientations

that is 00/900 & 00/450. It was recorded that the laminates with 00/450 orientations

having same thickness recorded higher flexural properties. Hence it can be concluded

that Fibres oriented along 00/450 have higher flexural properties than that of Fibres

with 00/900. The comparison was made for all the verities of the specimen, that is

between plain bi-woven glass, plain bi-woven graphite and plain bi-woven carbon

reinforced laminates. In all the cases it was found that laminates with 00/450

dominated in their behaviour.

Table 5.87 &5.88 shows the influence of the reinforcing Fibre type used that is

the influence of the glass, graphite and carbon Fibres on the flexural properties of the

specimen. It was observed that carbon Fibre reinforced laminates dominates in its

flexural properties with glass Fibres having the lower value in the series. But when

these laminates compared with some of the auto parts (presently used in automotive

vehicles), the laminated composites made of bi- woven fabrics of glass, graphite and

carbon laminates exhibited excellent properties. Even the glass Fibre laminates with

00/900 orientation which recorded the least flexural strength is observed to be having

better flexural properties.

TABLE-5.85, 5.86 shows the Effect of Fibre orientation for 2mm thick

specimens and 4mm thick specimens The detailed discussion is provided from

page No.172-177. Further the following aspects provides the broader spectrum

176

on the behaviour of the fibre reinforced laminates with different fibre

orientations.

The effect of fibre orientation on the flexural strength of fibre reinforced –epoxy

laminated composite material, with the variation in the orientation of the

reinforced fibres there will be a substantial variation in the flexural strength of

the laminated composites. The bi woven glass fibre reinforced laminated

composites and bi woven graphite fibre reinforced laminated composites of 2mm

and 4mm thickness with 0/900 and 0/450 orientation are considered in the present

investigation. It can be noted from the graph 5.21, 5.22, that the flexural strength

of laminates with 00/450 orientation exhibited excellent flexural strength than that

of the fibres with 00/900 orientation. Further graphite fibre reinforced laminated

composites with 00/450 orientation have higher flexural strength than glass fibre

laminated composites with the same fibre orientation. Further carbon fibre

reinforced laminated composites with 00/450 orientation have higher flexural

strength than graphite fibre laminated composites with the same fibre orientation.

Finally it can be concluded that 00/450 oriented laminates exhibits excellent flexural

properties than that of the other types of orientations of the laminates.

177

5.4: Inter laminar Shear Stress

TABLE -5.89: Details of specimen for short beam shear test

TYPE ORIENTATION THICKNESS

GLASS FIBRE 00/900 2mm

4mm

GRAPHITE 00/900 2mm

4mm

CARBON 00/900 2mm

4mm

Fig.5.25: Schematic of Short beam shear test.

The short beam shear test is performed as per ASTM D 2344 standards the

major difference between the short beam shear test and the flexural test is in its span

length in case of the flexural test the span length can be in the ratio of 16:1, 32:1 or a

maximum of 40:1. In case of the short beam shear test the ratio will be in the order of

4:1 to 9:1. In case of the flexural test the specimen is subjected to bending and in case

of the short beam shear test as the name itself indicates the specimens are subjected to

Inter laminar shear of the reinforced fibres. The short beam shear test identifies the de

lamination of the reinforced laminates.

P-Load

L-Span Length

h- Thickness of Specimen

178

TABLE-5.90: Table Showing the Specimen designation

Sample

Sample

Designation

Sample Type

Fibre

Orientation

Thickness

ILSS-GL2-S1/90

ILSS-A1

Glass Fibre

00/900

2mm

ILSS-GL2-S2/90

ILSS-A2

Glass Fibre

00/900

2mm

ILSS-GL2-S3/90

ILSS-A3

Glass Fibre

00/900

2mm

ILSS-GL4-S1/90

ILSS-A4

Glass Fibre

00/900

4mm

ILSS-GL4-S2/90

ILSS-A5

Glass Fibre

00/900

4mm

ILSS-GL4-S3/90

ILSS-A6

Glass Fibre

00/900

4mm

ILSS-GR2-S1/90

ILSS-A7

Graphite Fibre

00/900

2mm

ILSS-GR2-S2/90

ILSS-A8

Graphite Fibre

00/900

2mm

ILSS-GR2-S3/90

ILSS-A9

Graphite Fibre

00/900

2mm

ILSS-GR4-S1/90

ILSS-A10

Graphite Fibre

00/900

4mm

ILSS-GR4-S2/90

ILSS-A11

Graphite Fibre

00/900

4mm

ILSS-GR4-S3/90

ILSS-A12

Graphite Fibre

00/900

4mm

ILSS-CA2-S1/90

ILSS-A13

Carbon Fibre

00/900

2mm

ILSS-CA2-S2/90

ILSS-A14

Carbon Fibre

00/900

2mm

ILSS-CA2-S3/90

ILSS-A15

Carbon Fibre

00/900

2mm

ILSS-CA4-S1/90

ILSS-A16

Carbon Fibre

00/900

4mm

ILSS-CA4-S2/90

ILSS-A17

Carbon Fibre

00/900

4mm

ILSS-CA4-S3/90

ILSS-A18

Carbon Fibre

00/900

4mm

179

TABLE-5.91: Table Showing Load Vs Displacement Diagram -ILSS A1.

Specimen Designation : ILSS A1 ILSS-GL2-S1/900

P- Load N

P-210 N.

L- Span

L-17.37 mm.

h- Depth mm.

h-1.93 mm.

Short Beam Shear

Strength M Pa

Short Beam Shear Stiffness

M Pa

Maximum Load

Pmax. N

Displacement At. Pmax.

mm

6.46

67.74

210

3.1

180

TABLE-5.92: Table Showing Load Vs Displacement Diagram- ILSS A2.


P- Load N

P- 200 N.

L- Span

L-17.46 mm.

h- Depth mm.

h-1.94 mm.

Short Beam Shear

Strength M Pa


M Pa

Maximum Load

Pmax. N


mm

6.67

71.42

200

2.8

181

TABLE-5.93:Table Showing Load Vs Displacement Diagram -ILSS A3.


P- Load N

P-180 N.

L- Span

L-17.19 mm.

h- Depth mm.

h-1.91 mm.

Short Beam Shear

Strength M Pa


M Pa

Maximum Load

Pmax. N


mm

6.25

64.28

180

2.8

182



P- Load N

P- 810 N.

L- Span

L- 27.54 mm.

h- Depth mm.

h-3.06 mm.

Short Beam Shear Strength

M Pa


M Pa

Maximum Load

Pmax. N


mm

15.19

405

810

2.0

183



P- Load N

P-790 N.

L- Span

L- 27.81 mm.

h-Depth mm.

h-3.09 mm.


M Pa


M Pa

Maximum Load

Pmax. N


mm

14.90

438

790

1.8

184

TABLE-5.96: Table Showing Load Vs Displacement Diagram - ILSS A6.


P- Load N

P-780 N.

L- Span

L-27.94 mm.

h- Depth mm.

h-3.06 mm.


M Pa


M Pa

Maximum Load

Pmax. N


mm

14.58

458

780

1.7

185

TABLE- 5.97: Table Showing Load Vs Displacement Diagram - ILSS A7.

Specimen Designation : ILSS A7 ILSS-GR2-S1/900

P- Load N

P-300 N.

L- Span

L-19.71 mm.

h- Depth mm.

h-2.19 mm.

Short Beam Shear

Strength M Pa


M Pa

Maximum Load

Pmax. N


mm

8.07

115.3

300

2.6

186



P- Load N

P-220 N.

L- Span

L-19.98 mm.

h- Depth mm.

h-2.22 mm.

Short Beam Shear

Strength M Pa


M Pa

Maximum Load

Pmax. N


mm

5.6

81.4

220

2.7

187



P- Load N

P- 290 N.

L- Span

L-20.34 mm.

h- Depth mm.

h-2.26 mm.


M Pa


M Pa

Maximum Load

Pmax. N


mm

7.4

102.7

270

2.6

188



P- Load N

P-790 N.

L- Span

L-34.92 mm.

h- Depth mm.

h-3.88 mm.

Short Beam Shear

Strength M Pa


M Pa

Maximum Load

Pmax. N


mm

14.18

385.3

790

2.05

189



P- Load N

P- 850 N.

L-Span Length mm

L-34.47 mm.

h- Depth mm.

h-3.83 mm.

Short Beam Shear

Strength M Pa


M Pa

Maximum Load

Pmax. N


mm

14.04

404.7

850

2.1

190



P- Load N

P- 895 N.

L- Span

L- 35.01 mm.

h- Depth mm.

h-3.89 mm.


M Pa


M Pa

Maximum Load

Pmax. N


mm

14.51

426.1

895

2.1

191


Specimen Designation : ILSS A13 ILSS-CA2-S1/900

P- Load N

P- 300 N.

L- Span

L-19.44 mm.

h- Depth mm.

h-2.16 mm.


M Pa


M Pa

Maximum Load

Pmax. N


mm

7.83

96.7

300

3.1

192

TABLE-5.104: Table Showing Load Vs Displacement Diagram ILSS A14.


P- Load N

P-280 N.

L- Span

L-19.62 mm.

h- Depth mm.

h-2.18 mm.


M Pa


M Pa

Maximum Load

Pmax. N


mm

7.55

93.3

280

2.7

193



P- Load N

P-295 N.

L- Span

L-19.44 mm.

h- Depth mm.

h-2.16 mm.


M Pa


M Pa

Maximum Load

Pmax. N


mm

7.23

96.5

295

2.9

194



P- Load N

P-810 N.

L- Span

L- 35.55mm.

h- Depth mm.

h- 3.95 mm.


M Pa


M Pa

Maximum Load

Pmax. N


mm

14.21

405

810

2.0

195



P- Load N

P- 860 N.

L- Span

L-35.46 mm.

h- Depth mm.

h-3.94 mm.

Short Beam Shear

Strength M Pa


M Pa

Maximum Load

Pmax. N


mm

14.66

409

860

2.1

196



P- Load N

P-805 N.

L- Span

L-35.46 mm.

h- Depth mm.

h-3.94 mm.


M Pa


M Pa

Maximum Load

Pmax. N


mm

14.49

402

805

2.0

197

TABLE-5.109: Table showing short beam shear strength, stiffness, load, deflection glass 2mm.

Test Specimen

Designation

Glass 2mm

Short beam

Shear

Strength

Short beam

Shear

Stiffness

Load

Pmax. Deflection

N/mm2 N/mm N mm

Short

Beam

Shear

Test

ILA1-GL2-01 6.46 67.74 210 3.1

ILA2-GL2-02 6.67 71.42 200 2.8

ILA3-GL2-03 6.25 64.28 180 2.8

Average 6.46 67.8 197 2.9

TABLE-5.110: Table showing short beam shear strength, stiffness, load,

deflection glass 4mm.

Test

Specimen

Designation

Glass 4mm

Short beam

Shear

Strength

Short beam

Shear

Stiffness

Load

Pmax. Deflection

N/mm2 N/mm N mm

Short

Beam

Shear

Test

ILA4-GL4-01 15.19 405 810 2.0

ILA5-GL4-02 14.90 438 790 1.8

ILA6-GL4-03 14.58 458 780 1.7

Average 14.89 434 793 1.8

Fig.5.26: Short Beam Shear Strength Vs Specimen Designation Glass 2mm

198

Fig.5.27: Short Beam Shear Stiffness Vs Specimen Designation Glass 2mm

Fig.5.28: Short Beam Shear Strength Vs Specimen Designation Glass 4mm

Fig.5.29: Short Beam Shear Stiffness Vs Specimen Designation Glass 4mm

199

TABLE-5.111: Table showing short beam shear strength, stiffness, load, deflection Graphite 2mm.

Test Specimen

Designation

Graphite 2mm

Short beam

Shear

Strength

Short beam

Shear

Stiffness

Load

Pmax. Deflection

N/mm2 N/mm N mm

Short

Beam

Shear

Test

ILA7-GR2-01 8.07 115.3 300 2.6

ILA8-GR2-02 5.6 81.4 220 2.7

ILA9-GR2-03 7.4 111.5 290 2.6

Average 7.02 102.7 270 2.6

TABLE-5.112: Table showing short beam shear strength, stiffness, load, deflection Graphite 4mm.

Test Specimen

Designation

Graphite 4mm

Short beam

Shear

Strength

Short beam

Shear

Stiffness

Load

Pmax. Deflection

Short

Beam

Shear

Test

N/mm2 N/mm N mm

ILA10-GR4-01 14.18 385.3 790 2.05

ILA11-GR4-02 14.04 404.7 850 2.1

ILA12-GR4-03 14.51 426.1 895 2.1

Average 14.24 405.3 845 2.08

Fig.5.30: Short Beam Shear Strength Vs Specimen Designation Graphite 2mm

200

Fig.5.31: Short Beam Shear Stiffness Vs Specimen Designation Graphite 2mm

Fig.5.32: Short Beam Shear Strength Vs Specimen Designation Graphite 4mm

Fig.5.33: Short Beam Shear Stiffness Vs Specimen Designation Graphite 4mm

201

TABLE-5.113: Table showing short beam shear strength, stiffness, load, deflection Carbon 2 mm.

Test Specimen

Designation

Carbon 2mm Short beam

Shear

Strength

Short beam

Shear

Stiffness

Load

Pmax. Deflection

N/mm2 N/mm N mm

Short

Beam

Shear

Test

ILA13-CA2-01 7.83 96.7 300 3.1

ILA14-CA2-02 7.55 93.3 280 3.0

ILA15-CA2-03 7.23 96.5 295 2.9

Average 7.53 95.5 291 3.0

TABLE-5.114: Table showing short beam shear strength, stiffness, load,

deflection Carbon 4 mm.

Test Specimen

Designation

Carbon 4mm Short beam

Shear

Strength

Short beam

Shear

Stiffness

Load

Pmax. Deflection

N/mm2 N/mm N mm

Short

Beam

Shear

Test

ILA16-CA4-01 14.21 405 810 2.0

ILA17-CA4-02 14.66 409 860 2.1

ILA18-CA4-03 14.49 402 805 2.0

Average 14.45 405 825 2.0

Fig.5.34: Short Beam Shear Strength Vs Specimen Designation Carbon 2mm

202

Fig.5.35: Short Beam Shear Strength Vs Specimen Designation Carbon 4mm

Fig.5.36: Short Beam Shear Stiffness Vs Specimen Designation Carbon 4mm

Fig.5.37: Influence of thickness on Short Beam Shear Strength and Shear Stiffness

203

TABLE-5.115: Influence of thickness on short beam shear strength and Stiffness

Measured Parameter

Glass Fibre laminate

Graphite Fibre Laminate

Carbon Fibre laminate



N/mm2 6.46 14.89 7.02 14.24 7.53 14.45


N/mm 67.8 434 102.7 405.3 95.5 405

TABLE-5.116: Influence of Fibre Type on the Short Beam Shear Strength and

Shear Stiffness.

Measured parameter

2mm Thick Laminates 4mm Thick Laminates

Glass Fibre

Graphite Fibre

Carbon Fibre

Glass Fibre

Graphite Fibre

Carbon Fibre


N/mm2 6.46 7.02 7.53 14.89 14.18 14.45


N/mm 67.8 102.7 95.5 434 405 405

From Table 5.115: it is observed that there is an increase in the shear

properties with the increase in the thickness of the laminate for all the fibre types

used. The Glass fibre reinforced laminate with 2mm thickness shows least shear

strength [6.46 N/mm2] and shear stiffness [67.8 N/mm], further carbon fibre

reinforced laminate with 4mm thickness holds the highest shear strength [14.45

N/mm2] and shear stiffness [405 N/mm].

From table 5.116: shows comparison of shear properties between three

different fibre reinforced composite laminates. It is observed that carbon fibre

laminates shows excellent shear strength when compared with graphite and glass fibre

laminates in all the cases.

204

Fig.5.38: Influence of thickness on the Short Beam Shear Strength

Fig.5.39: Influence of thickness on the Short Beam Shear Stiffness

Fig.5.40 a: Influence of Fibre Type on the Shear Strength 2mm Thick

205

Fig.5.40 b: Influence of Fibre Type on the Shear Stiffness 2mm Thick

Fig.5.41 a: Influence of Fibre Type on the Shear Strength 4mm Thick

Fig.5.41 b: Influence of Fibre Type on the Shear Stiffness 4mm Thick

206

For the sake of accuracy in determination of the inter laminar shear strength,

for each combination of pattern and sort of the resin used for polymerization, number

of specimens were tested experimentally, conforming to the appropriate standards.

For each specimen, the initial dimensions were measured, and then the maximal shear

force Fmax (N), i.e. the force causing the de lamination of the specimen, was

determined by means of the testing machine.

Table 5.109 to table5.114 shows the short beam shear strength, shear stiffness,

load and deflection for various specimens. Table 5.109 shows the shear test results for

glass fibre reinforced laminate of 2mm thick specimen. Table 5.110 shows the shear

test results for 4mm glass fibre reinforced laminates. Figure 5.26 shows the graph of

shear strength Vs specimen designation for glass 2mm thick specimen. Figure 5.27

shows the shear stiffness Vs specimen designation for 2mm thick specimen. Figure

5.28 and 5.29 shows the strength and stiffness graph for 4mm glass fibre reinforced

laminate specimen. Table 5.111 and table 5.112 shows the results of short beam shear

stress for 2mm and 4mm graphite fibre reinforced laminates. Figure 5.30 and 5.31

shows the strength and stiffness graph for 2mm thick graphite fibre reinforced

laminate. Figure 5.32 and 5.33 shows the graph of strength and stiffness Vs specimen

designation for 4mm thick graphite specimen. Similarly table 5.113 and 5.114 is for

carbon fibre reinforced specimen and corresponding figures 5.34, 5.35, 5.36, and 5.37

represents strength and stiffness Vs specimen designation for 2mm and 4mm carbon

fibre reinforced laminates correspondingly.

Table 5.115 shows the influence of thickness on short beam shear properties,

the various parameters measured are short beam shear strength, short beam shear

stiffness, maximum load and maximum deflection; it was observed that with the

increase in thickness of the specimen there was an appreciable amount of increase in

207

the shear properties of the specimens. Hence it can be concluded that the increase in

thickness of the specimen enhances the shear properties of the laminates. The same is

illustrated in figure 5.38 which shows the graph of strength Vs specimen designation

and thickness as variable. Figure 5.39 shows the graph of short beam shear stiffness

Vs different thickness specimens, which shows that the shear stiffness increases with

the increase in the thickness of the specimen.

Table 5.116 shows the influence of fibre type on the short beam shear

properties of the specimens. From the table it is evident that carbon fibre reinforced

laminates has the highest shear strength followed by graphite fibre reinforced

laminates and the least being the glass fibre reinforced laminate. Similarly carbon

fibre reinforced laminate has highest shear stiffness followed by graphite fibre

reinforced laminate and finally glass fibre reinforced laminate. Figure 5.40 and

5.41shows the graph for 2mm and 4mm thick specimens.

De lamination is a phenomenon that is observed in laminated structures

that are subjected to different kinds of loads. The de lamination initiates in the

structure which is subjected to critical stress. It is observed that the de

lamination initiates from the extreme fibres of the laminates, it is further

observed that the de lamination takes place layer after the layer. It is clearly

visible from the visual inspection that the de lamination is initiated from the

extreme fibres both in tension and compression side.

208

5.5 FAILURE ANALYSIS

Failure in the compression Side of the specimen occurred within the gage

section for most of the composite specimens and is less catastrophic than in

conventional coupons. The failure in the compression side in the specimen is believed

to originate from the Fibre ends. It was also noticed that the Fibres had fractured in

the outermost section of the top skin in the specimen where the axial cracks originate

there. The most significant result of this compression study is that the graphite

reinforced composite specimens and carbon reinforced composites did not display

evidence of failure that is normally observed in tests on conventional specimens when

compared with glass Fibres.

Fig. 5.42– Damaged carbon Fibre specimens due to flexural loading

Fig.5.43 – Damaged glass Fibre specimens due to flexural loading

Fig.5.44 – Damaged graphite specimens due to flexural loading

209

The influence of transverse loads on the flexural failure behavior on e-

glass/epoxy composite was investigated. Investigations revealed that composites are

indeed sensitive to flexural for stresses in the matrix-dominated transverse shear

mode. Further, the research gave strong indications that in some cases traditional Inter

laminar Shear (ILSS) failure criteria are somewhat conservative. Typical pictures of

the different failure mechanisms observed for laminated composites are presented in

Figures. For laminated composites the picture shows the main damage process,

composed of Fibres fracture in the compressive surface followed by de-laminations

between the layers. Probably, the zigzag aspect of the curves showed in Figure results

from several sequential Fibres breakage events. The drop of the ultimate load is a

consequence of the long de-laminations and catastrophic broken Fibres. For all

specimens tested the Fibres submitted to tensile stresses did not break and the main

failure process occurs in compression.

The visual inspection provides the macroscopic details of the type of failure

that the materials have under gone; more insight can be obtained from the

microscopic analysis.

The de-lamination is a phenomenon that is observed in

specimens/structures/beams subjected to flexural/bending load. The de

lamination initiates in the structure which are subjected to critical loading. It is

observed that the de lamination initiates from the extreme fibres of the

laminates. In case of the laminated composites it is observed that the de

lamination takes place layer after layer. It is clearly visible from the visual

inspection that the de lamination has initiated in the extreme fibres both on the

tension side and on the compression side.

210

5.6. FINITE ELEMENT ANALYSIS [FEA].

Fig. 5.45 - Meshed Model

Fig.5.46 - Deformation Plot

The design of laminated composite specimen is complicated by the number of

design variables and the interaction of the constituents of the composite system. Since

it is desirable to experimentally test the specimen, to create a small scale model with a

similar (close to identical) structural response. A prior Finite Element Analysis tool

has been utilized to understand the basic behavior of PMC’s subjected to simple

flexural load. The results enable the design community to select models and

211

prototypes so that realistic structural performance of polymer matrix composite

specimens at multiple scales can be addressed. The experimental efforts can be

extended to include uni-axial tension, compression, flexural & impact test with

appropriate constitutive equations.

The panels are discretized using SHELL element available in the commercial

package ANSYS. This element has 8 nodes and is constituted by layers that are

designated by numbers (LN - Layer Number), increasing from bottom to top of the

laminate. The last number quantifies the existent total number of layers in the

laminate (NL - Total Number of Layers). The element has six degrees of freedom at

each node: translations in the nodal x, y, and z directions and rotations about the nodal

x, y, and z-axes. Each layer is having thickness of 0.2 mm with nominal length of 150

mm and width of 12mm with total thickness of laminate maintained at 2mm.

TABLE-5.117: Elastic properties of the woven fabric composite laminae.

Elastic Properties Of The Woven Fabric

Composite Lamina

Properties Value

Elastic modulus E1=E2 (GPa) 16.70

Elastic modulus E3 (GPa) 7.85

Shear modulus in plane 1-2 G12(GPa) 2.45



Poisson ratio in plane 1-2 γ12 0.15

Poisson ratio in plane 1-3 γ13 0.46

Poisson ratio in plane 2-3 γ23 0.46 Fig.5.47: Showing the Laminae

reference Axis.

212

TABLE- 5.118 : Stacking sequence of the laminates-2mm 00/900.

FEA Specimen Designation : FEA Glass Fibre Laminate 2mm 00/900

Table representing the stacking sequence of the laminates for 2mm thick 900 specimens.

213

TABLE- 5.119: 8 nodes meshed model- 2mm 00/900.


8 Nodes meshed model showing the reaction forces for the 2mm 900 specimens.

214

TABLE-5.120: FEA analysis for Glass Fibre Laminate -2mm 00/900.


Maximum Load Pmax. N

Displacement At. Pmax.mm 500 2.476

The change in the colour indicates the variation in load; red colour indicates the critical/ maximum load that the specimen can with stand. Variation in the colour indicates the increase in loading or variation in loading. The maximum load is decided by the change in the colour and loading is stopped once critical load is attained. Failure of the specimen is determined with the colour code red colour indicates the failure point of the specimen.

215

TABLE-5.121: Stacking sequence for Glass Fibre Laminate -2mm 00/450.

FEA Specimen Designation : Glass Fibre Laminate 2mm 00/450

Table representing the stacking sequence of the laminates for 2mm thick 450 specimens.

216

TABLE-5.122: Table showing the 8 nodes meshed model- 2mm 00/450.


8 Nodes meshed model showing the reaction forces for the 2mm 450 specimens.

217

TABLE-5.123: Table Showing the FEA analysis for Glass Fibre Laminate -2mm 00/900




218





219





220

TABLE -5.126: FEA analysis for Graphite Fibre Laminate -2mm 00/450

FEA Specimen Designation : FEA Graphite Fibre Laminate 2mm 00/450


Displacement At. Pmax.mm

400

1.878

221

TABLE-5.127: FEA analysis for Graphite Fibre Laminate -2mm 00/900

FEA Specimen Designation : Graphite FRP 2 mm , 00/900



222


FEA Specimen Designation : Graphite FRP 4mm , 00/900



223


FEA Specimen Designation : Graphite FRP 4mm , 00/900



224

TABLE- 5.130: Comparison of Experimental & FEA results for Flexural test

Parameter

Experimental FEA

Load in N

Pmax

Deflection

mm

Load in N

Pmax

Deflection

mm

Glass fibre Reinforced

Laminate 2mm, 00/900 509 2.47 500 2.47


Laminate 2mm, 00/450 445 2.30 500 2.37


Laminate 4mm, 00/900 612 2.70 600 2.47


Laminate 4mm, 00/450 820 3.80 800 3.94

Graphite fibre Reinforced

Laminate 2mm, 00/900 428 2.12 400 2.38


Laminate 2mm, 00/450 438 1.93 400 1.87


Laminate 4mm, 00/900 714 3.00 740 3.30


Laminate 4mm, 00/450 685 2.72 700 3.00

Carbon fibre Reinforced

Laminate 2mm, 00/900 650 2.90 678 3.12


Laminate 2mm, 00/450 776 2.40 789 2.48


Laminate 4mm, 00/900 988 2.50 1012 2.65


Laminate 4mm, 00/450 1306 2.30 1321 2.52

225

The following specific aims were addressed in order to understand the

underlying behaviour of PMC’s using FEM as a tool.

1. Finite Element flexural Analysis of polymer laminated composites specimens

of varying fibre type and thicknesses have been performed and various data

are recoded. Analysis of the behaviour of PMC when subjected to flexural

load is also recorded.

2. Effort to select an appropriate element to mesh the model [SHELL 99] to

satisfy the behaviour of PMC’s was successfully implemented.

3. Convergence criteria to improve the accuracy of the results have been adopted.

4. Post-processing features were carried to obtain the results such as

Displacement contours, Orientation contours etc.

5. Plotting graphs such as Load-Deflection curve to obtain the stiffness of the

composite specimen.

6. Fig 5.45 & Fig 5.46 indicates the meshed pattern and deformation plot of

specimen subjected to flexural load. The displacement value is 1.432mm for a

load of 100N. This is in well agreement with the experimental values of 1.38

mm (approx.)

7. In similar way, FE simulation was carried out for various load and

corresponding deformation were recorded for 4mm specimens also.

8. Table 5.118 to table 5.129 shows the various FEA plots for different Fibres

and different orientations of the Fibres are plotted. Table 5.130 shows the

comparison of the experimental values with the FEA analysis results it was

found that the values are well correlated and are with in the 10% error criteria.

226

TABLE-5.131: Comparative properties of automotive parts of polymer composites and plain bi-woven laminates.

Automotive Part/

Material

Flexural Strength

MPa

Flexural Modulus

Gpa

Bumper Beam/Polyester 110 25

Seat/ poly propelene 70 20

Load floor/Poly propelene 80 20

Hood/ Polycabonate 100 30

Radiator support/polyethylene 130 40

Roof panel/epoxy 80 20

Braid glass polyester –I beams/ Automotive Structural applications.

[Wind shield frame, Head lamp supports, Sill of fender brackets].

I Beam -1 150.5 ---

I Beam-2 237.9 ---

IBeam-3 292.0 ---

Un reinforced clear -cast polyester resins (roof panels/floor panels/Interior panels)

Orthophthalic 80 ---

Isophthalic 130 ---

BPA Fumarate 110 ---

Chlorendic 120 ---

Vinyl ester 140 ---

Fibre Glass – polyester resin composites (Glass content 40%) Automotive bumpers,

Floor Panels, Body panels.

Orthophthalic

Glass content % weight 170 220

5.5 6.9

30 40

Isophthalic 30 40

190 240

5.5 7.5

BPA

Fumarate

25 35 40

120 160 190

5.1 8.27 8.96

Chlorendic 24 34 40

120 160 190

5.9 6.8 9.6

Vinyl ester 25 35 40

110 260 220

5.4 9.5 8.8

227

Aluminum sheet [Body panels] 140 70

Stainless steel

[Body panels &structural applications]

210-

240

190

Low carbon steel [Wheel] 190 210

Neat resin casting (A material) 129 3.6

80pphA;20 pph CaCo3 (B Material) 109 4.3

74pphB;26pph 2.5cm long chopped strand

(Cmaterial)

183 6.10

Three dimensional braided graphite –epoxy properties as a function braid pattern

[25.4mm thick].

AS4 3K1X1 885.3 84.5

AS4 6K1X1 739.8 95.2

Celion 6K1X1 1063

T300,30K 1X1 813.5 77.5

T300, 8 harness satin fabric 689.5 65.5

Table 5.131 provides the Flexural strength and flexural stiffness for various

automotive parts made of polymer composites and metallic components. From the

table it is evident that the flexural strength and the flexural stiffness observed are

much less than the flexural strength and flexural stiffness values of that of plain bi-

woven glass, bi-woven graphite and plain bi-woven carbon reinforced laminates.

Hence form this it is clearly evident that for most of the structural and for various non

structural applications the plain bi-woven laminates are recommended depending

upon the intricacies of the design. The new data established using plain bi-woven

glass, graphite and carbon Fibre reinforced laminates with different orientations help

the design community to choose alternative materials.

chapter 5 results and discussions -...

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