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Proceedings of the 2nd

International Conference on Current Trends in Engineering and Management ICCTEM -2014

17 – 19, July 2014, Mysore, Karnataka, India

51

ANALYSIS OF TENSILE BEHAVIOR HYBRID CARBON -

JUTE FIBER RENIFORCED EPOXY COMPOSITE

Sandeep. B1, Dr. K.S Keerthi Prasad

2, Girish. T.R

3

1PG Student, Department of Mechanical Engineering, VVIET, VTU (Karnataka), India

2Professor, Department of Mechanical Engineering, VVIET, VTU (Karnataka), India

3Assistant Professor, Department of Mechanical Engineering, KSIT, VTU (Karnataka), India

ABSTRACT

Hybrid composites have unique features that can be used to meet diverse and competing design requirements in

a more cost-effective way than either - advanced or, conventional composites. The Natural-polymer hybrid composites

reinforced with carbon fiber and jute with three different orientations - 0°, 30° and 45° using epoxy resin is fabricated by

hand lay-up process. The tensile test is carried out to study the tensile behavior of the developed hybrid composite.

Results obtained shows that for 0° orientation have better tensile strength when compared with 30°& 45. By Ansys, the

analysis results are matching with the specimens tested data.

Keywords: Carbon Fiber, Tensile Strength, Jute, Orientation, Hybrid.

1. INTRODUCTION

The advancement in the material science and manufacturing processes has led to emergence of new

materials, one such material is reinforcement based polymer composite. Reinforced polymer composite possesses

very high specific stiffness and strength. This has led to their application in many fields such as aerospace,

automobile, marine, sports equipments and even in recreational goods. Very often there might be a need for these

materials to operate under high friction and non-lubricated conditions. To operate reliably under such severe hostile

condition; these materials require very good mechanical property. With several advances made in understanding the

behavior of composite materials, many fiber-reinforced polymer composite materials are finding increasing use as

primary load-bearing structures and also in a wide range of high technology engineering applications [1]. The ability

to tailor composites, in addition to their attributes of high stiffness-to weight and strength-to-weight ratios, fatigue

resistance, corrosion resistance, and lower manufacturing costs, makes them very attractive when compared with

conventional metals for use in many naval, aerospace, and automotive structural components [2]. High strain rate

loading is probable in many of the applications where fiber-reinforced polymer composites find use as candidate

materials. It has always been a cause for concern that the mechanical properties of composite materials may be poor

at high rates of strain. Hence, study of how the mechanical properties of these composites would change with strain

rate is warranted to be able to design structures that would not fail prematurely and unexpectedly at high loading

rates [6, 7].Evaluation of mechanical testing being carried out on a scientific basis in the second half of the

nineteenth century when metals were the most common engineering material. The use of high performance

composite materials, as distinct from ‘reinforced plastics’, as major load carrying materials began almost a century

later, and it follows that the test methods initially used to test composites were based very closely on ‘metallic’

techniques.

INTERNATIONAL JOURNAL OF MECHANICAL ENGINEERING

AND TECHNOLOGY (IJMET)

ISSN 0976 – 6340 (Print)

ISSN 0976 – 6359 (Online)

Volume 5, Issue 9, September (2014), pp. 51-55

© IAEME: www.iaeme.com/IJMET.asp

Journal Impact Factor (2014): 7.5377 (Calculated by GISI)

www.jifactor.com

IJMET

© I A E M E




52

Testing of metals is not a difficult task, being aided by the strain hardening isotropic homogeneous nature

of the material [3]. At its simplest, a piece of stock material can be pulled in a testing machine and fail in its mid

length: locally reducing the cross-section of the test piece can ensure that failure occurs away from the grips. It is

important to understand that, where composite materials are concerned, there are two separate and possibly distinct

aims when carrying out a materials test. The first is to establish fundamental material properties for subsequent use

with structural analysis and design techniques [4]. The second aim is to determine the properties, or investigate the

behavior, of an existing material. This is likely to involve testing material with fibers lying at a number of angles to

the principal loading direction [5]. Natural polymer hybrid composites have become popular due to their ability to

modify the mechanical properties by incorporating the different reinforcements. From literature survey it is clear that

incorporation of natural and synthetic reinforcements, they have positive effect on mechanical properties.

2. EXPERIMENTAL DETAILS

Fig 1: Hand Lay-up Method

Carbon and jute fiber woven mate is used as a reinforcing material in epoxy composite. K-10 is used as

hardener. Dry hand lay-up technique was employed to fabricate the composites. The release film was placed on the

lower surface of the mould coated with anti adhesive gent. Carbon fiber woven mat is placed on it, on which a

mixture of matrix system (consists of matrix material of epoxy resin plus hardener k-10 was used) is coated with

help of a brush. The stacking procedure was followed: placing of the carbon fiber woven mat one at the bottom

followed by jute and at the top again the carbon fiber thus forming a natural – polymer hybrid composite by coating

with the mixture prepared well on it and covering film was again used to complete the stack. To ensure approximate

thickness of the sample, a spacer was used. At the last again release film coated with anti adhesive agent was kept

and on it another large granite stone was again placed over it to apply enough load on it was also coated with anti

adhesive agent in order to aid the ease of separation on curing. Enough load was ensured and then it was allowed to

cure for a day at room temperature. Test samples according to ASTM D-638 (ASTM STANDARDS) were prepared

from the cured sheet using cut-off machine.

2.1 Tensile Testing

Fig 2: Computerized Universal Testing Machine

Computerized Universal testing machine which uses modern software for material test and analysis is used.

A sophisticated data gathering algorithm might be expected to adjust the rate of data collection in conjunction with

varying rates of change in load or strain, and so on. Most testing machine software is intended to be used in routine

testing and permits automatic calculation of information such as elastic modulus, and statistical analysis of the

results. Stress and strain data are to be taken by the computer software called Nexygen Plus Material test and

analysis, from a printed graph. The Composite materials are usually gripped using some form of ‘friction grip’,

where the load is transferred to the specimen through gripping faces which are roughened with serrations or a cross-

cut pattern. A fine-scale roughening is recommended for use with composites in order to spread the gripping force

over the largest possible area and to minimize damage to the specimen. Parallel clamping grips, positively closed by

manual or hydraulic means, allow the operator to control the gripping force on the specimen. Ideally, this should be

no more than is necessary to grip the material under test until maximum load is reached. The lack of any yielding




53

mechanism in composites means that even small misalignments, and the resultant bending, may result in large local

stresses, so that accuracy of alignment is important if reliable results are to be obtained. The strain measurement

technique is normally done by the use of extensometer. To avoid damaging the extensometer it should be removed,

or released from the specimen, prior to failure, as the sudden, almost explosive, release of the large amount of elastic

energy stored by composites specimens can easily wreck even the most robust extensometer. After measurement and

inspection, the specimen can be mounted in the grips. The centre line of the specimen should be aligned with the axis

of the testing machine so as to eliminate Bending and asymmetric loading. An extensometer is being used, this

should be attached to the centre of the specimen and the initial gauge length measured. A small preload may be

applied to the specimen before the extensometer is attached. Adequate guards should be placed round the specimen,

or test machine, if there is any possibility of an explosive failure. Start the machine, slowly the specimen is

uniformly loaded. The loading is done on the specimen until it breaks and finally the computer will record the

necessary data. Automatically the stress– strain graph is generated which includes all the features likely to be found

in a loading curve, including evidence of changes in stiffness, progressive failure and so on.

Fig 3: Specimens before and after failure

Table 1: Tensile properties of 0° orientation

Sl. No Maxi. Load

in N

Stress at

Maxi. Load

in MPa

Young’s Modulus

in MPa

1

3896.69 87.68 7086.49


Sl. No Maxi. Load

in N

Stress at

Maxi. Load

in MPa

Young’s Modulus

in MPa

1

3179.57 71.55 6585.02


Sl. No Maxi. Load

in N

Stress at

Maxi. Load

in MPa

Young’s Modulus

in MPa

1

3626.02 81.59 5753.83




54

3. RESULTS AND DISCUSSION

The tensile strength of carbon and jute fiber reinforced with epoxy composite is found to be 87.68 MPa for

0° orientation. The variation of the tensile strength of the hybrid composite is not much influenced by varying the

fiber orientation. Fig 4, 5 & 6. Shows the stress Vs strain plot obtained under tensile loading for carbon and jute fiber

reinforced – epoxy composite with 0°, 30° & 45° orientations. For 0° orientation, it exhibited better result, then the

remaining. The composite with orientations of 30° and 45° showed the decreased tensile strength. It was observed

that the lowest values of tensile strength were seen with 30° and 45° orientation in carbon and jute fibers reinforced

– epoxy composite shown in Fig 5 and 6 respectively. From the tables 1, 2 & 3 for different orientation with carbon

and jute fiber – epoxy composite, therefore for 0° orientation young’s modulus for composite showed optimal value.

Fig 4: Stress Vs Strain for 0° orientation Fig 5: Stress Vs Strain for 30° orientation

Fig 6: Stress Vs Strain for 45° orientation

Fig 7: Comparison of Ultimate Tensile Stress

From the fig 7, it indicates the comparative result of ultimate tensile stress of the developed hybrid

composite. For 0° orientation, the ultimate tensile stress high when compared with 30° and 45° orientations.




55

4. FEA ANALYSIS

Finite Elemental analysis is carried out to investigate the various parameter of Natural – polymer hybrid

composite material. For the tested specimen of 0° orientation, the von misses’ stresses developed in the natural

polymer hybrid composite is analyzed, its values indicate 99.79 MPa as a matching value with the results obtained

from the tested once as shown in the fig 8.

Fig 8: Contour plot of Von-mises stress for 0

0orientation

5. CONCLUSIONS

The Natural – polymer hybrid composite consists of carbon and jute fiber reinforced with epoxy composite

have been experimentally evaluated and studied for varying orientation and the same is analyzed using Ansys

software and the following conclusions were drawn:

• The hybrid composite consisting of carbon – jute fiber reinforced with epoxy composite for 0° orientation

showed a better tensile strength and can withstand the strength of 87.68 MPa.

• Generally composite materials, particularly if they contain a large proportion of 0° fibers, have substantially

linear stress–strain characteristics but it is not uncommon for the curve to show Nonlinearities at the start of

the test.

• Tensile test results of hybrid composite with 0° orientation showed a better tensile strength, compared to 30°

and 45°.

• It can be seen that there is only a marginal decrease in maximum stress when compared with 30° & 45°

orientation.

• Finally the natural – polymer hybrid composite with 0° orientation resulted in optimal.

• By the data obtained from the result of analysis, which is carried out by ansys software. For 0° orientation the

stresses developed is 99.79 MPa, which is 12.11% is more the experimental result. This shows that the values

are closing to each other and resulted in optimality.

6. REFERENCES

[1] ASTM D3039M,”Standard test method for tensile properties of polymer matrix composite materials”,

American Society for Testing and Materials, 100 Barr Harbor Drive, West Conshohocken, PA 19428,

USA,Vol 15.03, 1997.

[2] S T Burr, P G Ifju and D H Morris, “A method for determining critical strain gage size in anisotropic

materials with large repeating unit cells”, Experimental Techniques, September/October, 25–27, 1995.

[3] Xinran Xiao, “Dynamic tensile testing of plastic materials”, General Motors Corporation, MC 480-106- 710,

30500 Mound Road, Warren, MI 4800-055, USA Received 1 August 2007; accepted 15 September 2007.

[4] L J Hart-Smith, “Generation of higher composite material allowable using improved test coupons”,

36th

International SAMPE Symposium, 1991.

[5] Takeda, N.; Wan, L. “In High Strain Rate Effects on Polymer, Metal and Ceramic Matrix Composites and

Other Advanced Materials”, ASME Vol. 48, pp. 109–113.1995.

[6] ASTM Hand Book for testing of advanced composite materials.

[7] Prashanth Banakar1, H.K. Shivananda “Preparation and Characterization of the Carbon Fiber Reinforced

Epoxy Resin Composites” ISSN: 2278-1684 Volume 1, Issue 2, PP 15-18, May-June 2012.

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