Journal of Engineering Science and Technology (JESTEC) - …jestec.taylors.edu.my/Vol 13 issue 11...

Journal of Engineering Science and Technology Vol. 13, No. 11 (2018) 3710 - 3728 © School of Engineering, Taylor’s University

3710

MODELLING OF GLASS FIBRE REINFORCED POLYMER (GFRP) FOR AEROSPACE APPLICATIONS

ABHAY SHIVANAGERE1, S. K. SHARMA2, P. GOYAL2,*

1Amity Institute of Aerospace Engineering, of Amity University Noida,

Uttar Pradesh, India 2Quality Assurance Enhancement Department, Amity University, Noida,

Uttar Pradesh, India

*Corresponding Author: [email protected]

Abstract

Glass Fibre Reinforced Polymer (GFRP) composite material is used in many

engineering applications due to its high strength to weight ratio and many other

mechanical properties. In this article, special focus is done on the

micromechanics of the composites. The bi-directional and 45 degrees angled

specimen are tested mechanically and they were used for simulated calculations

in the Helius Composite Autodesk software. The applications, which utilize the

unique properties of such fabricated composites, are cited in this paper and future

research needs are identified.

Keywords: Composite materials; Epoxy resin; GFRP; Mechanical properties;

Strength.

Modelling of Glass Fibre Reinforced Polymer (GFRP) for Aerospace . . . .3711

Journal of Engineering Science and Technology November, 2018, Vol. 13(11)

1. Introduction

Fibre reinforced plastics have been widely used for manufacturing different

structural parts of aircraft and spacecraft because of their advantageous physical

and mechanical properties such as high specific strength and specific stiffness [1-

4]. Fibre reinforced plastics are of many different kinds, which prominently include

the Glass Fibre Reinforced Plastic (GFRP) as well as the Carbon Fibre Reinforced

Plastic (CFRP) [5-7]. In this paper, the main focus is laid upon the Glass Fibre

Reinforced Plastic (GFRP), especially on the fibre orientation angle, which is 90-

degree composite and a 45-degree rotated composite. The paper deals with the

applications of the GFRP composite in aerospace and engineering fields. In an

aircraft the applications of GFRP are used indoors, rubber sealing, landing gears,

fuselage body, tail spoiler, body, which result in 20 to 30% weight savings over

metal parts [2, 8, 9].

As explained by Ugural and Fenster [10], Glass Fibre Reinforced Polymers

(GFRP) have been extensively studied by the researchers as they have many

applications in industry such as structural component, storage tanks, and

automotive application. Furthermore, GFRP tends to have an advantage from the

economical point of view. According to Kim and Mayer [11], GFRP is categorized

under polymeric composite in which, polymer resin acts as the matrix and is later

reinforced by glass fibre. The addition of filler into the polymer matrix resulted in

excellent mechanical and physical properties in the GFRP composite.

Hybrid composite is the reinforcement of a common matrix by two or more

types of fibre. Based on studies by Ugural and Fenster [10], the essential objective

for developing this type of composite is to possess the advantages of its

constituents. Hybrid composites are more advanced and better than the

conventional fibre reinforced composites. Hybrid composites can be formed either

way by having more than one reinforcing phase and a single matrix phase or

multiple reinforcing phases with multiple matrix phases.

Hybrid composites have better flexibility as compared to other fibre

reinforced composites. Usually, they combine a high modulus fibre with the low

modulus fibre. The high modulus fibre provides the load-bearing qualities and

better stiffness whereas low modulus fibre makes the composite more durable

and low in cost.

As stated by Yuan and Goodson [3] and Lacovara [5], the mechanical

properties of a hybrid composite can be varied by altering the volume ratio and

stacking sequences of various plies. Based on a study by Mallick [12], previous

works on a hybrid of E-glass fibre/Kevlar 29 fibre in polyester resin showed that

the hybrid composite performed better at high impact velocity than the monolithic

glass fibre composite.

2. Fabrication and Testing

Hand lay-up method is used for manufacturing the composite, which is used in the

present study, is showed in Figs. 1 to 6. This is the oldest and simplest method used

to manufacture the composite material. Here, a mat of glass whiskers is used as a

fibre and Araldite AW 106 is used as a resin with hardener HW 231. Specifications

of specimen are in Table 1. The properties of specimens are mentioned in Table 2.

3712 A. S. Anilshankar et al.


After preparation, specimens were tested for tensile test, density test, percentage

elongation and Rockwell hardness test.

Fig. 1. Fabrication process showing the araldite

being poured to create a layer of epoxy resin.

Fig. 2. Fabrication process showing the glass fibres

placed at 45 degree being applied with the epoxy resin.

(a) Araldite AW 106 and hardner. (b) Mould for hand layup.



(c) Fiber placement. (d) Epoxy application.

Fig. 3. Fabrication process showing various steps

and the araldite used for the fabrications.

(a) Layers of fibers. (b) Layers of epoxy. (c) Layers of

composite.

Fig. 4. Fabrication process of the GFRP bidirectional composite.

(a) Weights added for equal

compression.

(b) Weights added for equal and

uniform distribution of load.

(c) Close view of nuts and bolts. (d) Layers are drying.

Fig. 5. After the mould is completely covered the weights are added

to make sure even bonding between the glass fibres and the epoxy.



(a) Hand layup applying epoxy. (b) Sheets of fiber and setup.

(c) Weights applied. (d) Setup for a new fiber specimen.

(e) Applying epoxy to layers. (f) Weights added.

Fig 6. Miscellaneous pictures to show

the fabrication process and the preparations.

Table 1. Specifications of bi-directional 90° and angle-ply 45° composites.

Parameters Specimen 1

(bi-directional 90°)

Specimen 2

(angle-ply 45°)

Orientation 90° 45°

Layers of fibres 8 8

Thickness 4.25 mm 4 mm

Loading 20 kg 12 kg

Curing time 24 hours 24 hrs

Weight of resin 225 gm 225 gm

Composites



Table 2. Properties of bi-directional 90° and angle-ply 45° composites.

Properties Specimen 1

(bi-directional 90°)

Specimen 2

(angle-ply 45°)

Tensile strength 88 N/mm2 92 N/mm2

Elongation at break 0.81% 0.88%

Density 1.14 g/cc 1.15 g/cc

Hardness 88 HRL 87 HRL

Compressive strength 110 N/mm2 N/mm2

3. Results and Discussion

The bi-directional 90° and angle-ply 45° composites were simulated with the

obtained properties with the Helius Composite Autodesk software to obtain the

micromechanics of manufactured composites such as Young’s Modulus, critical

frequency, Poisson’s Ratio, Shear Modulus, deflection, the angle of twist and

coefficient of thermal expansion as shown in Fig. 7.

Fig. 7. Young’s Modulus in the x-direction

for bi-directional 90° and angle-ply 45°.

In the comparative analysis of Young’s Modulus in the x-direction of bi-

directional 90° and angle-ply 45°, it shows that the EX of angle-ply is more than the

bi-directional composite. It means pressure taken by angle-ply is more than bi-

directional composite. Angle-ply can be used in an aircraft where pressure applied

is more in the x-direction. The software screenshot of Figs. 8 and 9 give the details

of the Youngs Modulus in x-direction.

In the comparative analysis of Young’s Modulus in the y-direction of bi-

directional 90° and angle-ply 45°, it shows that the Ey of bi-directional is more than

the angle-ply composite. Bi-directional can be used in an aircraft where pressure

applied is more in the y-direction. Bi-directional composites can be used in an

aircraft where pressure applied is more in the y-direction. The software screenshot

of Figs. 10 and 11 give the details of the Youngs Modulus in y-direction.

Figure 12 shows the critical frequency of both the composites. The critical

frequency of angle-ply is more than the bi-directional composite. It shows that the



angle-ply can sustain more vibrations comparatively. This means angle-ply can

withstand more vibrational loads. Therefore, angle-ply can be used in an aircraft

where there are a lot of vibrational loads. Like in wings, landing gears and the parts

that vibrate. The software screenshot of Figs. 13 and 14 gives the details of the

critical frequencies.

Fig. 8. 2D and 3D properties of the

GFRP Bi directional and the input details.



Fig. 9. The 2D and 3D prpoerties of the GFRP

angle-ply 45 degrees and the input details.

Fig. 10. Young’s Modulus in y-direction




Fig. 11. Young’s Modulus in z-direction


Fig. 12. Critical frequency of bi-directional 90°

and angle-ply 45° composites.



Fig. 13. Shows the plate analysis and the plate geometry details.

with the critical frequency mentioned in radians per second

for the GFRP bi-directional composite.



Fig. 14. The plate analysis, plate geometry

and the critical frequency for the GFRP angle-ply 45 degrees.

Figure 15 shows the Poisson’s Ratio in xy-direction of both the composites. The

Poisson’s Ratio of angle-ply is more than the bi-directional composite. The

software screenshot of Figs. 8 and 9 give the details Poisson’s Ratio in xy-direction.

Figure 16 shows the shear modulus in xy-direction of both the specimens. The shear

modulus of angle-ply is more than bi-directional composite. It means composites align

to 45° takes more shear modulus than bi-directional composite. Angle ply can be used

in an aircraft where shear loads applied is more in the xy-direction. In an aircraft, the

shear loads are more in the wings, fuselage, tail parts. The software screenshot of Figs.

8 and 9 gives the details of the Shear Modulus in xy-direction.

Fig. 15. Poisson’s Ratio of bi-directional 90° and angle-ply 45° composites.

Fig. 16. Shear Modulus of bi-directional 90° and angle-ply 45° composites.



Figure 17 shows the total deflection in both the specimens. The total deflection

in the bi-directional composite is more than the angle-ply. It shows that the bi-

directional composite deflects more than angle-ply under loading. Angle-ply can

be used in an aircraft where the deflection is more, but bi-directional composite can

be used where the deflection is less like in cockpit. The software screenshot of Figs.

18 and 19 give the details of the total deflections.

The GFRP bidirectional as well as GFRP angle-ply 45 degrees both were taken

into the sandwich analysis. Figure 18 shows the deflection and the total deflection

for the bi-directional composite. The same value is used to plot the graph in Fig.

17. In a similar way in Fig. 19, it shows the deflection and the total deflection for

the angle-ply 45 degrees. The same value is used to plot the graph and compare

both the composites in Fig. 17.

The graph shows that there is a lot of variation in the total deflection of 2

composites. The angular ply is less deflected as compared to the bidirectional one.

This infers that the angular one would be better to use for applications where we

require fewer deflections and the bi-directional would be better to use for the

application where deflections required are higher.

Fig. 17. Total Deflection in bi-directional 90° and angle-ply 45° composites.



Fig. 18. Shows the sandwich geometry for the GFRP

bi-directional with the deflection.

Fig. 19. Shows the deflection and the sandwich analysis

for the GFRP angle-ply 45 degrees.

Figure 20 shows the angle of twist of both the specimens. The angle of twist of

the bi-directional composite is more than the angle-ply. The software screenshot of

Figs. 21 and 22 gives the details of the angle of twist.

Figure 23 shows that thermal expansion is more in bi-directional as compared to

angle ply. Therefore, bi-directional composites are useful in fuselage construction as

there is many temperature differences. The software screenshot Figs. 8 and 9, both

give the details of the coefficient of thermal expansion for justification..



The input details of the software are all described using the screenshots of Figs.

24 to 27 for both GFRP 45 degree and GFRP bi-directional.

Fig, 20. Angle of twist for bi-directional 90° and angle-ply 45° composites.

Fig. 21. Angle of twist of GFRP bidirectional

composite both in radians and in degrees.



Fig. 22. Angle of twist of GFRP angle play 45 degrees

both in radians and degrees.

Fig. 23. Co-efficient of thermal expansion

for bi-directional 90° and angle-ply 45° composites.



Fig. 24. Glass fibre and epoxy as lamina input details.

Fig. 25. S2 Glass epoxy as lamina input details.

Fig. 26. Araldite properties input details.



Fig. 27. Properties of e glass, s2 fibreglass and glass hc input details.

4. Conclusions

The conclusions of the above results are as follows:

Angle-ply is better when loads are applied in x-direction because it has a good

young’s modulus in the x-direction.

Bi-directional GFRP is better when loads are applied in y and z-direction

because it has better values of Young's Modulus in both y and z-directions.

Coming to shear modulus, it is the coefficient of elasticity. In xy plane, the 45°

has a better value of shear modulus than bi-directional. It means the elastic

properties of 45° composite are better than the bi-directional ones.

Poisson’s Ratio is the ratio of transverse strain to axial strain. The 45° GFRP

has less Poisson’s Ratio than the bi-directional. This indicates that the 45°

GFRP takes less transverse strain as compared to the bi-directional GFRP.

Co-efficient of thermal expansion is more for bi-directional GFRP. This

confirms that the bi-directional can withstand more thermal stresses than the

45° GFRP.

Critical frequency is the frequency just before the resonance phenomenon. The

critical frequency of 45° GFRP is more than the bi-directional. This implies

that 45 degrees GFRP can take up a lot of vibrations as compared to bi-

directional composite.

Total deflection of 45° composite is less as compared to bi-directional. This

implies that the deflection is less and the stability of the composite is good.



The bi-directional and 45° have almost near values of deflection. Any

composite must deflect and elongate to be applied under elastic conditions.

Angle of twist that each composite can bear is approximately the same. They

both were made from the same epoxy and glass fibre and the only angle of

fibre was changed.

The shear moment is same for both the composites.

This is concluded that angle-ply composites are the best to use in aircraft. The

reason being the composite’s critical frequency is more than that of bi-directional

composite, which is one and the sole reason for our conclusion although the

GFRP behaves less stable in other properties and in some, they both match the

values approximately.

In an aircraft, there are a lot of vibrations especially in engines, fuselage and the

landing gears. So 45° GFRP is a better choice in terms of frequency of vibrations.

But if we see in terms of stress, strain and Poisson’s Ratio, then bi-directional

composite would be a better choice.

Nomenclatures

Ex Young's Modulus in x-direction

Ey Young's Modulus in y-direction

Ez Young's Modulus in z-direction

Wcr Critical Frequency

Rad/s Radians per second

NUxy Poisson's Ratio

Gxy Shear Modulus

Abbreviations

CFRP Carbon Fibre Reinforced Plastic

GFRP Glass Fibre Reinforced Plastic

CTE Coefficient of Thermal Expansion

References

1. Gibson, A.G. (2003). The cost effective use of fibre reinforced composites

offshore. Research Report 039, University of Newscastle Upon Tyne,

Newscastle Upon Tyne, United Kingdom.

2. Stringfellow, W.D. (1987). Make-up of fiberglass tubulars. Proceedings of the

SPE Production Technology Symposium. Lubbock, Texas, 15 pages.

3. Yuan, Y; and Goodson, J. (2007). Special report: Hot-wet downhole conditions

affect composite selection. Oil and Gas Journal, 105(34), 52-63.

4. Ciaraldi, S.W.; Alkire, J.D.; and Huntoon, G.G. (1992) Fiberglass firewater

systems for offshore platforms. Proceedings of the Offshore Technology

Conference. Houston, Texas, 8 pages.

5. Lacovara, B. (2008). What exactly are composites? Do we take the definition

for granted? Arlington, Virginia: Composites Fabricators Association.

6. Jones, R.M. (1999). Mechanics of composite materials (2nd ed). Philadelphia,

Pennsylvania: Taylor & Francis, Inc.



7. Dash, P.K.; and Chatterjee, A.K (2004). Effects of environment on fracture

toughness of woven carbon-epoxy composite. Journal of the Institution of

Engineers (India), 85(1), 1-9.

8. Buchanan, G.R., (1988). Mechanics of materials. New York: HRW Inc.

9. Soutis, C. (1997). Compressive strength of unidirectional composites:

Measurement and predictions. ASTM STP 1242, 168-176.

10. Ugural, A.C.; and Fenster, S.K. (1995). Advanced strength and applied

elasticity (3rd ed.). Englewood Cliffs, New Jersey: Prentice Hall.

11. Kim, B.W.; and Mayer, A.H. (2003). Influence of fibre direction and mixed-

mode ratio on delamination fracture toughness of carbon/epoxy laminates.

Composite Science and Technology, 63, 695-713.

12. Mallick, P.K. (2007). Fiber reinforced composites. Materials, manufacturing

and design (3rd ed.). Boca Raton, Florida: CRC Press.

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