Mechanical Characterization of Carbon Fibre Reinforced Epoxy Composite

Mechanical Characterization of Carbon Fibre Reinforced Epoxy Composite

Shanavas S.

Department of Mechanical Engineering, YCEW, Kollam, Kerala – 691538, India.

Abstract

This paper investigates the mechanical properties

1. Mechanical Characterization

   (tensile strength, compressive strength, shear

   strength, flexural strength) and density measurement

   1. Tensile Test

of epoxy resin (F584) reinforced by carbon fibre

fabric (PW). The aim of the current work is to

replace metals with Carbon fibre epoxy composite where high strength, low weight and damping

The tensile test was performed on circular rod of diameter 15 mm and gauge length of 70 mm. The

characteristics are predominant. The specimens are

tensile test was conducted in a universal testing

prepared by hand lay-up process with 0/900 orientation and experimentation was performed to determine the mechanical properties. The results show that carbon fibre reinforced epoxy present better mechanical properties, high specific strength

machine (Model UTN 60), hydraulically operated with loading capacity of 600 KN, at room temperature as shown in figure 2.1. An extensometer is used to measure the elongation, thereby found out strain and finally the modulus of elasticity. The

and good damping characteristics.

1. Introduction

   Composite materials are material which consists of two or more material phase that are combining to produce a material that has superior properties than

   ultimate tensile strength and youngs modulus were

   found out by the test.

   individual

   constituent.

   Technologically the most

   important among composites are those in which the dispersed phase is in the form of fibre. The common fibres in commercial use are glass, carbon, graphite and Kevlar. Carbon fiber reinforced epoxy composite

   is an extremely strong and light fiber reinforced

   polymer which contains carbon fibers. The properties of composite depend on the layouts of the carbon fiber, the proportion of the carbon fibers relative to the polymer and the processing method. Carbon fibre epoxy has high strength and less density compared to

   Figure 2.1: Tensile Test

   cast iron and steel. F584-epoxy matrix laminates have better mechanical properties in the tensile and compressive tests than 8552 composites. Also PW

   carbon fibre fabric reinforcement has better flexural

   o T =

   External axial tensile load

   Original cross sectional area of the specimen

   and interlaminar shear properties than 8HS for both matrices [3] Mechanical properties of carbon fibre epoxy differ with fibre orientation of laminates. The tensile & flexural strengths are superior in case of 90 degree fibre orientation [4]. Multi fibre composites have more strength than single fibre composites [5].

   where, T = Ultimate tensile strength.

   E = Stress

   Strain

   where, E = Youngs modulus (Tensile modulus).

2. 2. Compression Test

Compression testing was performed on cubic

specimen of dimension (45×45×45) mm3, using

compression testing machine (Model AIM 317E AN), electrically operated with three load gauges of loading capacity of 2000 KN. Samples were placed

between the top and bottom surfaces of a

compression fixture as shown in figure 2.2. The

compressive strength and poissons ratio were found out by the test.

Figure 2.3: Shear Test

2.4. Flexural Test

The

procedure for the three-point bending

tests

followed the ASTM standard D790. That standard, however, specifies a length/width ratio of 16. The test

was

performed on square rod

of cross sectional

dimension (25×25) mm2 and span length of 400 mm.

The

flexural experiment was

conducted

on an

universal testing

machine (Model UTN

60),

o c =

Figure 2.2: Compression Test

Maximum compressive load cross-sectional area

hydraulically operated with loading capacity of 600 KN. Flexural test (3 point) was conducted at room temperature as shown in figure 2.4. The flexural strength was found out by the test.

where, c = compressive strength

Poissons ratio = Transverse strain

Longitudinal strain

2.3. Shear Test

The double shear tests were performed on circular rod of diameter 15 mm using double shear test set up and conducted in a universal testing machine (Model

UTN 60), hydraulically operated with loading

capacity of 600 KN, at room temperature as shown in figure 2.3. The shear strength was found out by the test.

= shear load

2A

where, = Shear strength,

3PL

b 2bt2

Figure 2.4: Flexural Test

=

A = Shear area

where, b = Flexural strength P = Rupture load

L = Support span

b = width of specimen.

t = thickness of specimen

Table 3.2: Specific Strength

2. 5. Density Measurement

Cubic specimen of dimension (45×45×45) mm3 was

used for

density measurement. The

density and

specific strength were found out.

Mass

Density =

Volume

Specific strength = Strength

Density

Figure 3.1: Specific strength

4. Conclusion

The objective of the current work is to replace metals

with

Carbon fibre epoxy composite where

high

strength, low weight and damping characteristics are predominant. Results show that the mechanical

Figure 2.5: Density Measurement

properties (tensile

strength, compressive strength,

3. Results

shear strength, flexural strength) are superior for carbon fibre epoxy composite when compared with

cast iron. The modulus of elasticity of the fibre

Table 3.1: Material properties

reinforced resin is less compared to cast iron, which shows its good damping characteristics. The density of the composite is very less when compared with cast iron, which shows its high strength to weight ratio (specific strength).

5. References

1. Jane Maria Faulstich De Paiva, Alexandre De Nadai dos Santos, Mirabel Cerqueira Rezende, Mechanical and

   Material Name		Cast Iron [2]	Carbon fibre reinforced epoxy
   Material Properties	Tensile Strength (MPa)	200	634.11
   	Tensile Modulus (GPa)	152	137.92
   	Compressive Strength (MPa)	500	520.50
   	Shear Strength (MPa)	260	271.76
   	Flexural Strength (MPa)	50	483.84
   	Poissons Ratio	0.28	0.25
   	Density (gm/cc)	7.34	1.284

   morphological characterizations of

   carbon fiber

   fabric

   reinforced epoy composites used in aeronautical field,

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5. Smrutisikha Bal, Experimental study of mechanical and electrical properties of carbon nanofiber/epoxy composites, Materials & Design, Vol.31, No.5 (2010), pp. 2406-2413.

6. S.Y. Fu, B. Lauke, E. Mader, C.Y. Yue, X. Hu, Tensile properties of short-glass-fiber- and short-carbon-fiber- reinforced polypropylene composites, Composites: Part A: Applied Science and Manufacturing, Vol.31 (2000), pp.11171125.

7. Robert M. Jones, Mechanics of Composite Materials, Taylor & Francis, Second Edition 1999.

8. Faculty of Mechanical Engineering, PSG College of Technology, Design Data Data book of engineers, July 2003.