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Torsional and compression properties of cylindrical glass fiber reinforced polymer composite
Materials Today: Proceedings xxx (xxxx) xxx
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Torsional and compression properties of cylindrical glass fiber reinforced polymer composite S. Senthil Gavaskar a, S. Madhu b,⇑ a b
RMK College of Engineering and Technology, Tiruvallur, Tamilnadu 601206, India Saveetha School of Engineering, Saveetha Institute of Medical and Technical Sciences, Tamilnadu 602105, India
a r t i c l e
i n f o
Article history: Received 24 October 2019 Received in revised form 29 November 2019 Accepted 4 December 2019 Available online xxxx Keywords: Glass Fiber Composite Cylinder Peak Torque Compression
a b s t r a c t Composite materials play a vital role in many industrial applications. Researchers are working on fabrication of new composite materials worldwide to enhance the applicability of these materials. GFRP (Glass Fiber reinforced polymer) is a composite material made of a polymer matrix reinforced with glass fiber. Fiber reinforced polymer composites are known for their stiffness and strength in tension and compression along its axis, controllable electrical conductivity, and low coefficient of thermal expansion, good fatigue resistance and suitability for the production of complex shape materials. This study-project comprises of the manual fabrication of Glass Fiber reinforced polymer - hollow cylindrical component with varying layers of different types of glass fiber fabrics and testing the torsion and compression strength of the specimens. The different types of glass fiber fabrics include pure unidirectional fiber form, veil mats, and woven fabrics. Finally a comparative analysis is conducted among the different kinds of specimens fabricated and suitable application is found based on their strength. Thus the result of the study shows the influence of varying layers of the glass fiber fabrics on their strength and the possibility of replacing the low power transmitting metallic shafts with composite (GFRP) shafts. Ó 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Materials Engineering and Characterization 2019.
1. Introduction A composite material is a material made from two or more constituent materials with significantly different physical or chemical properties that, when combined, produce a material with characteristics different from the individual components [1]. The individual components remain separate and distinct within the finished structure. The new material may be preferred for many reasons: common examples include materials which are stronger, lighter, or less expensive when compared to traditional materials. Since a composite material which could be less cost and reduced weight is capable of replacing the conventional materials it has to be tested in terms of various strength based on their replacing application and material. Likewise a lots research works are being conducted in the composite world [2]. In this work in this paper, the fish scale which is obtained from the outermost part of fish skin is utilized as filler material. Seven different volume fraction of fish ⇑ Corresponding author.
scale were taken with epoxy matrix material to prepare composite plate. The composite specimens were fabricated by hand layup method. The mechanical properties such as tensile, flexural and impact tests were evaluated as per ASTM standards. The addition of fish scale filler to reinforce the epoxy composite has considerably increased the mechanical properties of the composites [3]. Portunus sanguinolentus shell waste was powdered and used as untreated fillers in jute fabrics reinforced epoxy composites. Then portunus sanguinolentus shell waste powder was treated with chemicals to perform fat removal, deproteination, decarbonization and deacetylation to obtain treated portunus sanguinolentus shell filler. Three different composites were developed with traditional hand layup process consisting of four layers jute fabrics that were filled with 10 wt% untreated portunus sanguinolentus shell filler, chemical treated 10 wt% portunus sanguinolentus shell filler and unfilled one. The thermo-mechanical and fracture morphologies were assessed by tensile, flexural, compression, shear, impact, hardness thermo gravimetric analysis, Fourier-transform infrared spectroscopy and scanning electron microscopy analysis [4]. Glass
E-mail address: [email protected] (S. Madhu). https://doi.org/10.1016/j.matpr.2019.12.024 2214-7853/Ó 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Materials Engineering and Characterization 2019.
Please cite this article as: S. Senthil Gavaskar and S. Madhu, Torsional and compression properties of cylindrical glass fiber reinforced polymer composite, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.12.024
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fiber is material made from extremely fine fibers of glass. Fiberglass is a lightweight, extremely strong, and robust material. Although strength properties are somewhat lower than carbon fiber and it is less stiff, the material is typically far less brittle, and the raw materials are much less expensive. Its bulk strength and weight properties are also very favourable when compared to metals, and it can be easily formed using molding processes. Glass is the oldest, and most familiar, performance fiber. There are several types of glass fibers in use. They are A-glass (Alkali-lime glass with little or no boron oxide), ECR glass (Electrical/Chemical Resistance; alumino-lime silicate with less than 1% w/w alkali oxides, with high acid resistance), C-glass (alkali-lime glass with high boron oxide content, used for glass staple fibers and insulation), D-glass (borosilicate glass, named for its low Dielectric constant), R-glass (Alumina silicate glass without MgO and CaO with high mechanical requirements as reinforcement), and S-Glass (Alumina silicate glass without CaO but with high MgO content with high tensile strength). Glass fibers are useful because of their high ratio of surface area to weight. However, the increased surface area makes them much more susceptible to chemical attack [5]. By trapping air within them, blocks of glass fiber make good thermal insulation, with a thermal conductivity of the order of 0.05 W/(mK). The strength of glass is usually tested and reported for ‘‘virgin” or pristine fibers those which have just been manufactured. The freshest, thinnest fibers are the strongest because the thinner fibers are more ductile. The more the surface is scratched, the less the resulting tenacity [6]. Because glass has an amorphous structure, its properties are the same along the fiber and across the fiber. Humidity is an important factor in the tensile strength. Moisture is easily adsorbed, and can worsen microscopic cracks and surface defects, and lessen tenacity. In contrast to carbon fiber, glass can undergo more elongation before it breaks [7]. There is a correlation between bending diameter of the filament and the filament diameter. The viscosity of the molten glass is very important for manufacturing success. During drawing (pulling of the glass to reduce fiber circumference), the viscosity should be relatively low. If it is too high, the fiber will break during drawing. However, if it is too low, the glass will form droplets rather than drawing out into fiber [8,9]. The mechanical characteristics like tensile, impact strength and flexural rigidity were evaluated. With the results obtained it is found that kevlar epoxy composite provides better mechanical characteristics than aluminum. In this work, the possibility of replacing aluminum with Kevlar reinforced epoxy composite material is investigated for various applications viz. manufacturing of bus body frame, bullet proof vests, automobile body, sports applications, fire proof clothing, military helmets [10]. Carbon fibre epoxy composites were machined by abrasive jet machine using threaded and unthreaded nozzle. Delamination in the machined holes was investigated. From this work it was seen that, the internal threaded nozzle reduced the delamination damage comparably [11]. Glass fibre epoxy composites were machined with AJM using nozzle with and without internal threads. Surface roughness (Ra) was investigated on the GFRP composites. This work showed that, the internal threaded nozzle reduced the surface roughness as compared with the hole machined using unthreaded nozzle [12]. Machining time, material removal rate, kerf characteristics (top and bottom) were evaluated in the carbon fibre composites machined using threaded and unthreaded nozzle [13]. Surface roughness (Ra) was investigated in the CFRP composites machined by AJM. Threaded and unthreaded nozzles were used for machining the carbon fibre composites. This work reported that threaded nozzle reduced the surface roughness in the CFRP composites [14]. Abrasive jet machining with conventional nozzles (various diameters) were used for machining glass fibre composites. Machining time, top kerf and bottom kerf were
evaluated. Mathematical modeling was performed for confirming the results [15]. Many research works have been carried out regarding the glass fiber reinforced polymer to test its strength in various aspects. In most of the researches the glass fiber reinforced composite was fabricated in the form of a strip (bar) and has been subjected to a series tests to examine its mechanical properties such tensile strength, compressive strength, torsion strength, wear, flexural strength and so on. Also these set of tests has been conducted by changing the orientation of the fiber in the specimen (strip) to determine its strength degradation based of the varying orientation of the fiber. In other set of researches the glass fiber polymer is reinforced with the concrete and fabricated in the form of a rod to find its compressive strength and torsional behaviour. In particular this glass fiber reinforced concrete research work has been applied in real life application as support column for large structures. The way in which our study project differs from the various studies made on the glass fiber reinforced polymer in the history is that in our work the glass fiber reinforced only with the epoxy resin has been fabricated in the form of a hollow cylindrical specimen with four number of variations in the layers of the specimen. These specimens are subjected to torsion and compression loading in order to find the strength degradation among these four variations which are nothing but the different types of fiber orientations in the layers of the specimen.
2. Materials and method As we discussed earlier an individual structural glass fiber is both stiff and strong in tension and compression. Although it might be assumed that the fiber is weak in compression, it is actually only the long aspect ratio of the fiber which makes it seem so; i.e., because a typical fiber is long and narrow, it buckles easily. On the other hand, the glass fiber is weak in shear. Therefore, if a collection of fibers can be arranged permanently in a preferred direction within a material, and if they can be prevented from buckling in compression, the material will be preferentially strong in that direction. Furthermore, by laying multiple layers of fiber on top of one another, with each layer oriented in various preferred directions, the material’s overall stiffness and strength can be efficiently controlled. In fiberglass, it is the plastic matrix which permanently constrains the structural glass fibers to directions chosen by the designer. With chopped strand mat, this directionality is essentially an entire two dimensional plane; with woven fabrics or unidirectional layers, directionality of stiffness and strength can be more precisely controlled within the plane. In this comparative study for the analysis of variation of the mechanical properties of the GFRP specimen with respect to the different types of orientation through various layers of the specimen the following types of Glass fiber mats (Fabrics) are used. The different types of orientations in which the fiber fabrics were arranged in various layers for the comparative analysis is explained below. In Type-1 all the four layers of the hollow cylindrical specimen are wrapped with pure unidirectional fiber fabrics. In Type-2 the innermost and the outermost layers are wrapped with the unidirectional fiber fabrics (Zero degree - orientation) and the middle two layers are wrapped with Chopped Strand Mat (CSM). [0°/CSM/CSM/0°]In Type-3 all the four layers of the hollow cylindrical specimen are wrapped with the Bi-directional (0°–90° orientation) glass fiber fabrics. [Bi- 4 layers]. In Type-4 the innermost and the outermost layers are wrapped with unidirectional fiber fabrics (Zero degree - orientation). The second layer from the outermost layer is wrapped with 135° oriented ( 45°) fiber fabrics and the second layer from the innermost layer is wrapped with 45° oriented fiber fabrics. It
Please cite this article as: S. Senthil Gavaskar and S. Madhu, Torsional and compression properties of cylindrical glass fiber reinforced polymer composite, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.12.024
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should be noted that both 45° and 45° orientation fiber fabrics are cut from the unidirectional fiber mat for the required dimension using an angled template. 3. Experimental procedure The mandrel used for this investigation is the PVC pipe with outer diameter of 25 mm and length of 350 mm. Then it is made into two pieces by cutting it in the middle. Then the two cut pieces are joined into a single piece with the help of a cellophane tape. The polythene sheet with 297 mm length is wrapped around the pipe closely without any air gaps with the help of the tape. The glass of 1000 mm length and 1000 mm width is taken. The surface of the glass plate is cleaned with the help of the acetone to remove the impurities if any present on it. Wax polish is used to enhance and protect the wooden furniture and floor giving them a natural soft sheen and a matt finish. This wax polish is used as a releasing agent in this manual reinforcement process. A thin layer of the wax polish is coated over the polythene sheet that has been wrapped over the pipe for the easy removal of the specimen after curing. A thin layer of wax is also coated over the glass plate to avoid sticking of the FRP during the reinforcement process. A small bowl made of ceramic is taken. It is cleaned with the acetone solution to remove the impurities if any present in it. The resin (Araldite LY556) equal to the weight of the fiber is taken in the bowl. The hardener equal to 10 percent weight of the resin is mixed with the resin in the ceramic bowl. The resin and hardener has to be finely mixed in the bowl. The glass fiber mat of required dimension and required fiber orientation has been cut from the glass fiber roll with the help of fiber cutter. A thin layer of resin hardener mixture is applied over the wax coated glass plate. Then the cut piece of glass fiber of required dimension is placed over it. Then the resin hardener mixture is spread over the glass fiber mat. The mixture is rolled over the glass fiber mat finely with the help of a metal roller which is when the fiber reinforcement with the polymer takes place. Now the wax coated mandrel is kept over the glass fiber mat and it is tightly wrapped over the mandrel by rolling it. Finally the wax coated Polythene sheet is wrapped over the rolled glass fiber specimen and allowed to dry. The setup is allowed to dry freely for few hours. The curing time is the time required for this wet reinforced specimen is about 12 h. The specimen is removed from the mandrel after the curing by twisting at the edges of the mandrel and pulling it outwards. This specimen is then cut into required size for testing. The removed specimen will be having uneven edges. Thus it is cut for 1 cm length at both the ends for which the allowance is provided at the initial stages while cutting the fiber from the roller for each specimen. Also the specimen is grinded at the edges for proper surface finish.
itself around 29.67 mm. So we planned to join the test specimen with the machine holder with the help of a T-joint. For this purpose the specimen was drilled with 8 mm drill bit at a distance of 6 mm from both the ends. This T-joint comprises of two parts. One is a flat metal strip of 3 mm thickness, length 12 mm and width 2 mm with an 8 mm hole drilled at each of its ends. This strip has to be aligned parallel to the specimen axis where one end of this strip is inserted inside the work holder of the machine and the other end is penetrated inside the hollow cylindrical specimen and is aligned in such a manner that the axis of the drilled hole of the metal strip must be coaxial with the drilled hole in the test specimen. The second part of the T-joint is a metal rod of 8 mm diameter which has to be inserted in the lateral direction through all the aligned holes of both the specimen and the metal strip. In this same way the specimen is connected to the work holder of the machine with the help of T-joint on both sides. It should be noted that all the drilled holds are provided with suitable tolerances for perfect alignment and adjusted for perfect fastening before the start of the (twisting) experiment. The test specimen is perfectly aligned and hold in the machine holder with the help of the T-joint with tight grip. Both the Data Acquisition system and the Torsion Testing Machine are connected and activated. As the test specimen is fixed at one end it is rotated manually (Twisting action) at the other end with the help of a lever connected with the motor without electrically switching ON the motor. For each of the 10 rotations the corresponding Torque and the angle of twist values are noted down from the Digital Data Acquisition system. It should be noted that the frequency of rotation must be constant. This is continued until the specimen breaks by the twisting action. Then the break point value is retrieved from the Data Acquisition system. Then the graph is plotted between the torque value and the corresponding angle of twist to indicate the variation of twist with the angle of twist and the peak torque value. The twisting force can also be applied by switching ON the electrical motor. But if done so only the break point can be obtained but the graph cannot be plotted. 4. Result and discussion 4.1. Peak torque analysis From the above mentioned experimental results (Fig. 1) it could be concluded that the specimen with 45° glass fiber orientation has the maximum torque carrying capacity and the specimen with bidirectional glass fiber orientation has the minimum torque carrying capacity. The specimen with CSM glass fiber orientation has torque carrying capacity less than the specimen with 45° fiber orientation but
3.1. Torsion testing
PEAK TORQUE PEAK TORQUE[Nm]
Torsion tests twist a material or test component to a specified degree, with a specified force, or until the material fails in torsion. The twisting force of a torsion test is applied to the test sample by anchoring one end so that it cannot move or rotate and applying a moment to the other end so that the sample is rotated about its axis. The rotating moment may also be applied to both ends of the sample but the ends must be rotated in opposite directions. The forces and mechanics found in this test are similar to those found in a piece of string that has one end held in a hand and the other end twisted by the other. Since the specimen holder in the conventional torsion testing machine can hold only a rod of maximum diameter 12 mm or rectangular strip of width 12 mm we are in need of preparing additional arrangement for the holding purpose as the mean diameter of the specimen we fabricated is
100 50 PEAK TORQUE 0
UNI
45
CSM
BI
FIBER ORIENTATION Fig. 1. Peak torque Analysis.
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greater than the specimen with unidirectional glass fiber orientation. This tearing test is an unusual type of test which is performed to find the edge tearing resistance of the cylindrical specimen which is made of Glass fiber. The conventional tensile testing machine is employed to perform this tearing test. The basic intension of this test is to determine the maximum load this fiber specimen withstands before it tears of at edges after applying axial load by penetrating the support hook at the top and bottom of the specimen and pulling apart. The specimen we fabricated for the analysis is of 22 mm length. For hanging the specimen in the hooks of the tensile testing machine the specimen is drilled with a 8 mm drill bit at a distance of 6 mm from both the edges of the cylindrical specimen in the same manner as it is drilled for torsion test. The specimen is fixed in the machine with the help of the hooks at both the ends and it is tightened to the optimum level for applying the axial load. The value of load in the dial indicator is adjusted to zero. The axial load is applied at the bottom with the help of the lever provided in the machine. The value of load is noted down for the corresponding 0.1 mm increment in the axial deflection of the specimen. Both the axial deflection and the Load values are noted down until the specimen tears of at the edges. 4.2. Peak load analysis for tearing From the above mentioned experimental results (Fig. 2) it could be concluded that the specimen with 45° glass fiber orientation has the maximum capacity to resist tearing. It can able to withstand load greater than 2500 N. Since the machine we used can apply only load upto 2500 N, we cannot find the accurate value. The specimen with unidirectional glass fiber orientation can resist more tear load than the specimen with CSM fiberorientation. The specimen with bidirectional glass fiber orientation has the least capacity to withstand tear.
As mentioned earlier the one of the motto of the compression testing in this study is to compare the strengths of the cylindrical specimen among different aspect ratios. For this reason the original dimension (Length = 22 mm, Mean Diameter 29.67 mm) which could be taken as 100% is divided as 75%, 50%, 25% and thus 4 such specimens are prepared for each of the orientation types. Since we are also comparing the strengths among the 4 different types of fiber fabric orientations on the whole 16 such (4*4 = 16) GFRP hollow cylindrical specimens are prepared for the compression testing [15]. Thus all fabricated specimens which are of same length (22 mm) are cut according to the aspect ratios for before testing and their edges are surface grinded to achieve the plane end condition. After the performing the compression test by observing the deformation of the specimen it is found that the glass fiber hollow cylindrical specimen wont buckle in compression instead it deforms at the edge by enlarging itself in a flower pattern.
4.4. Peak load analysis for compression Among the unidirectional orientation glass fiber (TYPE-1) the specimen with aspect ratio 3.71 is having the ability to withstand the highest peak load (compressive) and the specimen with aspect ratio 7.41 is having the ability to withstand the lowest peak load (Fig. 3). The specimen with aspect ratio 1.85 withstands lesser peak load than that of 3.71 but the same specimen withstands greater peak load that than the specimen of aspect ratio 5.56. Among the unidirectional orientation glass fiber (TYPE-1) the specimen with aspect ratio 5.56 is having the highest cross head travel (compressive) for breaking and the specimen with aspect ratio 7.41 is having the lowest cross head travel (Fig. 4). The specimen with aspect ratio 1.85 has lesser cross head travel (CHT) than that of 5.56 but the same specimen has greater cross head travel (CHT) than the specimen of aspect ratio 3.71.
4.3. Compression testing
4.5. Cross head travel analysis for compression
Compression testing is a very common testing method that is used to establish the compressive force or crush resistance of a material and the ability of the material to recover after a specified compressive force is applied and even held over a defined period of time. The maximum stress a material can sustain over a period under a load (constant or progressive) is determined. The specimen is compressed and deformation at various loads is recorded. Compressive stress and strain are calculated and plotted as a stress– strain diagram which is used to determine elastic limit, proportional limit, yield point, yield strength and, for some materials, compressive strength.
Fig. 5 explains the comparison of unidirectional orientation with different aspect ratio among unidirectional orientation glass fiber (TYPE-1) the specimen with aspect ratio 5.56 is having the highest cross head travel (compressive) for breaking and the specimen with aspect ratio 7.41 is having the lowest cross head travel (CHT). The specimen with aspect ratio 1.85 has lesser cross head travel (CHT) than that of 5.56 but the same specimen has greater cross head travel (CHT) than the specimen of aspect ratio 3.71. Fig. 6 explains the comparison among various fiber orientations with aspect ratio-1.85. Among the glass fiber specimen of aspect ratio 1.85 unidirectional orientation glass fiber (TYPE-1) specimen
3000 2000 1000
PEAK LOAD
0 FIBER ORIENTATION Fig. 2. Peak Load analysis.
PEAK LOAD PEAK LOAD[KN]
PEAK LOAD[N]
PEAK LOAD 40 30
PEAK LOAD
20 10 0
7.41 5.56 3.71 1.85 L/D RATIO
Fig. 3. Comparison of unidirectional orientation with various aspect ratio.
Please cite this article as: S. Senthil Gavaskar and S. Madhu, Torsional and compression properties of cylindrical glass fiber reinforced polymer composite, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.12.024
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COMPRESSIVE STRENGTH
40 20
PEAK LOAD
0
UNI 45 CSM BI FIBER ORIENTATION
200
L/D RATIO
PEAK LOAD[KN]
PEAK LOAD
100 0
COMPRESSIVE STRENGTH 7.41 5.56 3.71 1.85
COMPRESSIVE STRENGTH[N/sq.mm] Fig. 4. Comparison of peak load for different fiber orientation.
CROSS HEAD TRAVEL
CROSS HEAD TRAVEL [mm]
Fig. 5. Comparison of unidirectional orientation with various aspect ratio.
CROSS HEAD TRAVEL
150 100
COMPRESSIVE STRENGTH
50 0
UNI 45 CSM BI
L/D RATIO
COMPRESSIVE STRENGTH COMPRESSIVE STRENGTH[N/sq.mm]
1.85
3.71
CROSS HEAD TRAVEL 5.56
4 3 2 1 0
7.41
CROSS HEAD TRAVEL [mm]
Fig. 7. Comparison of unidirectional orientation with various aspect ratio.
FIBER ORIENTATION
Fig. 8. Comparison among various fiber orientations with aspect ratio-1.85.
12 10 8
CROSS HEAD TRAVEL
6 4 2 0
UNI 45 CSM BI FIBER ORIENTATION
has greater compressive strength that than the specimen of aspect ratio 1.85 [17]. Among the glass fiber specimen of aspect ratio 1.85chopped strand mat layered glass fiber (TYPE-2) specimen is having the highest compressive strength (compressive) and the specimen with bidirectional orientation (TYPE-3) is having the lowest compressive strength (Fig. 8). The specimen with unidirectional orientation (TYPE-1) is having lesser compressive strength than the CSM (TYPE-2) but the same specimen has greater compressive strength than the 45° cross ply orientation glass fiber (TYPE-4) specimen.
Fig. 6. Comparison among various fiber orientations with aspect ratio-1.85.
5. Conclusions is having the highest CHT (compressive) and the specimen with bidirectional orientation (TYPE-3) is having the least CHT. The specimen with chopped strand mat layered glass fiber (TYPE-2) is having lesser CHT than the unidirectional (TYPE-1) specimen but the same specimen has greater CHT than the 45° cross ply orientation glass fiber (TYPE-4) specimen [16].
4.6. Compressive strength analysis Fig. 7 indicates the comparison of compressive strength. Among the unidirectional orientation glass fiber (TYPE-1) the specimen with aspect ratio 3.71 is having the highest compressive strength and the specimen with aspect ratio 7.41 is having the lowest compressive strength. The specimen with aspect ratio 5.56 has lesser compressive strength than that of 3.71 but the same specimen
From the torsion test performed and the comparative analysis conducted among the various fiber orientations incorporated glass fiber cylindrical specimen it could be concluded that the TYPE-4 specimen is having the highest torsional strength in comparison with other types. While the TYPE-3 specimen is having the least torsion strength. Thus the TYPE-4 specimen could be highly suggested for the low power transmitting torsional applications compared with other glass fiber specimen. From the tearing test performed with the help of the tensile testing machine and the comparative analysis conducted among the various fiber orientations incorporated glass fiber cylindrical specimen it could be concluded that the TYPE-4 specimen has tearing resistance in the surface more than 2500 N. But the actual tearing point is unfound. Whereas the TYPE-3 specimen has the least tearing resistance compared with other types. From the compression tests performed and the comparative analysis conducted among the various fiber orientations incorporated glass fiber cylindrical specimen it could
Please cite this article as: S. Senthil Gavaskar and S. Madhu, Torsional and compression properties of cylindrical glass fiber reinforced polymer composite, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.12.024
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be concluded that TYPE-1 and TYPE-2 specimens are having comparatively higher compressive strength than the TYPE-3 and TYPE-4 specimens. From the compression tests performed and the comparative analysis conducted among the various aspect ratios the glass fiber cylindrical specimen having the aspect ratio 7.41 is having the least compressive strength compared with other specimens of aspect ratios 5.56, 3.71 and 1.85. Thus the glass fiber hollow cylindrical fabricated with unidirectional orientation and chopped strand mat layers having lesser aspect ratios could be suggested for high axial compression loading applications. Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. References [1] T.P. Sathishkumar, S. Satheeshkumar, Naveen, Glass fiber-reinforced polymer composites - A review, J. Reinf. Plast. Compos. 33 (2014) 1258. [2] M.S. Ahmadi M.S. Johari M. Sadighi An experimental study on mechanical properties of GFRP braid pultruded composite rods Exp. Polym. Lett. Esfandeh 3 2009 No.9 [3] K. Ramesh Babu, V. Jayakumar, G. Bharathiraja, S. Madhu, Experimental investigation of fish scale reinforced polymer composite, Mater. Today Proc. (2019), https://doi.org/10.1016/j.matpr.2019.07.594. [4] P. Kumaran, S. Mohanamurugan, S. Madhu, R. Vijay, D. Lenin Singaravelu, A. Vinod, M.R. Sanjay, Suchart Siengchin, Investigation on thermo-mechanical characteristics of treated / untreated portunus sanguinolentus shell powder based jute fabrics reinforced epoxy composites, J. Ind. Text. (2019), https://doi. org/10.1177/1528083719832851. [5] P. Sangeetha, R. Sumathi, Behavior of glass fiber wrapped concrete columns under uniaxial compression, Int. J. Adv. Eng. Technol. 1 (1) (2010) 74–83.
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Please cite this article as: S. Senthil Gavaskar and S. Madhu, Torsional and compression properties of cylindrical glass fiber reinforced polymer composite, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.12.024
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Torsional and compression properties of cylindrical glass fiber reinforced polymer composite S. Senthil Gavaskar a, S. Madhu b,⇑ a b
RMK College of Engineering and Technology, Tiruvallur, Tamilnadu 601206, India Saveetha School of Engineering, Saveetha Institute of Medical and Technical Sciences, Tamilnadu 602105, India
a r t i c l e
i n f o
Article history: Received 24 October 2019 Received in revised form 29 November 2019 Accepted 4 December 2019 Available online xxxx Keywords: Glass Fiber Composite Cylinder Peak Torque Compression
a b s t r a c t Composite materials play a vital role in many industrial applications. Researchers are working on fabrication of new composite materials worldwide to enhance the applicability of these materials. GFRP (Glass Fiber reinforced polymer) is a composite material made of a polymer matrix reinforced with glass fiber. Fiber reinforced polymer composites are known for their stiffness and strength in tension and compression along its axis, controllable electrical conductivity, and low coefficient of thermal expansion, good fatigue resistance and suitability for the production of complex shape materials. This study-project comprises of the manual fabrication of Glass Fiber reinforced polymer - hollow cylindrical component with varying layers of different types of glass fiber fabrics and testing the torsion and compression strength of the specimens. The different types of glass fiber fabrics include pure unidirectional fiber form, veil mats, and woven fabrics. Finally a comparative analysis is conducted among the different kinds of specimens fabricated and suitable application is found based on their strength. Thus the result of the study shows the influence of varying layers of the glass fiber fabrics on their strength and the possibility of replacing the low power transmitting metallic shafts with composite (GFRP) shafts. Ó 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Materials Engineering and Characterization 2019.
1. Introduction A composite material is a material made from two or more constituent materials with significantly different physical or chemical properties that, when combined, produce a material with characteristics different from the individual components [1]. The individual components remain separate and distinct within the finished structure. The new material may be preferred for many reasons: common examples include materials which are stronger, lighter, or less expensive when compared to traditional materials. Since a composite material which could be less cost and reduced weight is capable of replacing the conventional materials it has to be tested in terms of various strength based on their replacing application and material. Likewise a lots research works are being conducted in the composite world [2]. In this work in this paper, the fish scale which is obtained from the outermost part of fish skin is utilized as filler material. Seven different volume fraction of fish ⇑ Corresponding author.
scale were taken with epoxy matrix material to prepare composite plate. The composite specimens were fabricated by hand layup method. The mechanical properties such as tensile, flexural and impact tests were evaluated as per ASTM standards. The addition of fish scale filler to reinforce the epoxy composite has considerably increased the mechanical properties of the composites [3]. Portunus sanguinolentus shell waste was powdered and used as untreated fillers in jute fabrics reinforced epoxy composites. Then portunus sanguinolentus shell waste powder was treated with chemicals to perform fat removal, deproteination, decarbonization and deacetylation to obtain treated portunus sanguinolentus shell filler. Three different composites were developed with traditional hand layup process consisting of four layers jute fabrics that were filled with 10 wt% untreated portunus sanguinolentus shell filler, chemical treated 10 wt% portunus sanguinolentus shell filler and unfilled one. The thermo-mechanical and fracture morphologies were assessed by tensile, flexural, compression, shear, impact, hardness thermo gravimetric analysis, Fourier-transform infrared spectroscopy and scanning electron microscopy analysis [4]. Glass
E-mail address: [email protected] (S. Madhu). https://doi.org/10.1016/j.matpr.2019.12.024 2214-7853/Ó 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Materials Engineering and Characterization 2019.
Please cite this article as: S. Senthil Gavaskar and S. Madhu, Torsional and compression properties of cylindrical glass fiber reinforced polymer composite, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.12.024
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fiber is material made from extremely fine fibers of glass. Fiberglass is a lightweight, extremely strong, and robust material. Although strength properties are somewhat lower than carbon fiber and it is less stiff, the material is typically far less brittle, and the raw materials are much less expensive. Its bulk strength and weight properties are also very favourable when compared to metals, and it can be easily formed using molding processes. Glass is the oldest, and most familiar, performance fiber. There are several types of glass fibers in use. They are A-glass (Alkali-lime glass with little or no boron oxide), ECR glass (Electrical/Chemical Resistance; alumino-lime silicate with less than 1% w/w alkali oxides, with high acid resistance), C-glass (alkali-lime glass with high boron oxide content, used for glass staple fibers and insulation), D-glass (borosilicate glass, named for its low Dielectric constant), R-glass (Alumina silicate glass without MgO and CaO with high mechanical requirements as reinforcement), and S-Glass (Alumina silicate glass without CaO but with high MgO content with high tensile strength). Glass fibers are useful because of their high ratio of surface area to weight. However, the increased surface area makes them much more susceptible to chemical attack [5]. By trapping air within them, blocks of glass fiber make good thermal insulation, with a thermal conductivity of the order of 0.05 W/(mK). The strength of glass is usually tested and reported for ‘‘virgin” or pristine fibers those which have just been manufactured. The freshest, thinnest fibers are the strongest because the thinner fibers are more ductile. The more the surface is scratched, the less the resulting tenacity [6]. Because glass has an amorphous structure, its properties are the same along the fiber and across the fiber. Humidity is an important factor in the tensile strength. Moisture is easily adsorbed, and can worsen microscopic cracks and surface defects, and lessen tenacity. In contrast to carbon fiber, glass can undergo more elongation before it breaks [7]. There is a correlation between bending diameter of the filament and the filament diameter. The viscosity of the molten glass is very important for manufacturing success. During drawing (pulling of the glass to reduce fiber circumference), the viscosity should be relatively low. If it is too high, the fiber will break during drawing. However, if it is too low, the glass will form droplets rather than drawing out into fiber [8,9]. The mechanical characteristics like tensile, impact strength and flexural rigidity were evaluated. With the results obtained it is found that kevlar epoxy composite provides better mechanical characteristics than aluminum. In this work, the possibility of replacing aluminum with Kevlar reinforced epoxy composite material is investigated for various applications viz. manufacturing of bus body frame, bullet proof vests, automobile body, sports applications, fire proof clothing, military helmets [10]. Carbon fibre epoxy composites were machined by abrasive jet machine using threaded and unthreaded nozzle. Delamination in the machined holes was investigated. From this work it was seen that, the internal threaded nozzle reduced the delamination damage comparably [11]. Glass fibre epoxy composites were machined with AJM using nozzle with and without internal threads. Surface roughness (Ra) was investigated on the GFRP composites. This work showed that, the internal threaded nozzle reduced the surface roughness as compared with the hole machined using unthreaded nozzle [12]. Machining time, material removal rate, kerf characteristics (top and bottom) were evaluated in the carbon fibre composites machined using threaded and unthreaded nozzle [13]. Surface roughness (Ra) was investigated in the CFRP composites machined by AJM. Threaded and unthreaded nozzles were used for machining the carbon fibre composites. This work reported that threaded nozzle reduced the surface roughness in the CFRP composites [14]. Abrasive jet machining with conventional nozzles (various diameters) were used for machining glass fibre composites. Machining time, top kerf and bottom kerf were
evaluated. Mathematical modeling was performed for confirming the results [15]. Many research works have been carried out regarding the glass fiber reinforced polymer to test its strength in various aspects. In most of the researches the glass fiber reinforced composite was fabricated in the form of a strip (bar) and has been subjected to a series tests to examine its mechanical properties such tensile strength, compressive strength, torsion strength, wear, flexural strength and so on. Also these set of tests has been conducted by changing the orientation of the fiber in the specimen (strip) to determine its strength degradation based of the varying orientation of the fiber. In other set of researches the glass fiber polymer is reinforced with the concrete and fabricated in the form of a rod to find its compressive strength and torsional behaviour. In particular this glass fiber reinforced concrete research work has been applied in real life application as support column for large structures. The way in which our study project differs from the various studies made on the glass fiber reinforced polymer in the history is that in our work the glass fiber reinforced only with the epoxy resin has been fabricated in the form of a hollow cylindrical specimen with four number of variations in the layers of the specimen. These specimens are subjected to torsion and compression loading in order to find the strength degradation among these four variations which are nothing but the different types of fiber orientations in the layers of the specimen.
2. Materials and method As we discussed earlier an individual structural glass fiber is both stiff and strong in tension and compression. Although it might be assumed that the fiber is weak in compression, it is actually only the long aspect ratio of the fiber which makes it seem so; i.e., because a typical fiber is long and narrow, it buckles easily. On the other hand, the glass fiber is weak in shear. Therefore, if a collection of fibers can be arranged permanently in a preferred direction within a material, and if they can be prevented from buckling in compression, the material will be preferentially strong in that direction. Furthermore, by laying multiple layers of fiber on top of one another, with each layer oriented in various preferred directions, the material’s overall stiffness and strength can be efficiently controlled. In fiberglass, it is the plastic matrix which permanently constrains the structural glass fibers to directions chosen by the designer. With chopped strand mat, this directionality is essentially an entire two dimensional plane; with woven fabrics or unidirectional layers, directionality of stiffness and strength can be more precisely controlled within the plane. In this comparative study for the analysis of variation of the mechanical properties of the GFRP specimen with respect to the different types of orientation through various layers of the specimen the following types of Glass fiber mats (Fabrics) are used. The different types of orientations in which the fiber fabrics were arranged in various layers for the comparative analysis is explained below. In Type-1 all the four layers of the hollow cylindrical specimen are wrapped with pure unidirectional fiber fabrics. In Type-2 the innermost and the outermost layers are wrapped with the unidirectional fiber fabrics (Zero degree - orientation) and the middle two layers are wrapped with Chopped Strand Mat (CSM). [0°/CSM/CSM/0°]In Type-3 all the four layers of the hollow cylindrical specimen are wrapped with the Bi-directional (0°–90° orientation) glass fiber fabrics. [Bi- 4 layers]. In Type-4 the innermost and the outermost layers are wrapped with unidirectional fiber fabrics (Zero degree - orientation). The second layer from the outermost layer is wrapped with 135° oriented ( 45°) fiber fabrics and the second layer from the innermost layer is wrapped with 45° oriented fiber fabrics. It
Please cite this article as: S. Senthil Gavaskar and S. Madhu, Torsional and compression properties of cylindrical glass fiber reinforced polymer composite, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.12.024
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should be noted that both 45° and 45° orientation fiber fabrics are cut from the unidirectional fiber mat for the required dimension using an angled template. 3. Experimental procedure The mandrel used for this investigation is the PVC pipe with outer diameter of 25 mm and length of 350 mm. Then it is made into two pieces by cutting it in the middle. Then the two cut pieces are joined into a single piece with the help of a cellophane tape. The polythene sheet with 297 mm length is wrapped around the pipe closely without any air gaps with the help of the tape. The glass of 1000 mm length and 1000 mm width is taken. The surface of the glass plate is cleaned with the help of the acetone to remove the impurities if any present on it. Wax polish is used to enhance and protect the wooden furniture and floor giving them a natural soft sheen and a matt finish. This wax polish is used as a releasing agent in this manual reinforcement process. A thin layer of the wax polish is coated over the polythene sheet that has been wrapped over the pipe for the easy removal of the specimen after curing. A thin layer of wax is also coated over the glass plate to avoid sticking of the FRP during the reinforcement process. A small bowl made of ceramic is taken. It is cleaned with the acetone solution to remove the impurities if any present in it. The resin (Araldite LY556) equal to the weight of the fiber is taken in the bowl. The hardener equal to 10 percent weight of the resin is mixed with the resin in the ceramic bowl. The resin and hardener has to be finely mixed in the bowl. The glass fiber mat of required dimension and required fiber orientation has been cut from the glass fiber roll with the help of fiber cutter. A thin layer of resin hardener mixture is applied over the wax coated glass plate. Then the cut piece of glass fiber of required dimension is placed over it. Then the resin hardener mixture is spread over the glass fiber mat. The mixture is rolled over the glass fiber mat finely with the help of a metal roller which is when the fiber reinforcement with the polymer takes place. Now the wax coated mandrel is kept over the glass fiber mat and it is tightly wrapped over the mandrel by rolling it. Finally the wax coated Polythene sheet is wrapped over the rolled glass fiber specimen and allowed to dry. The setup is allowed to dry freely for few hours. The curing time is the time required for this wet reinforced specimen is about 12 h. The specimen is removed from the mandrel after the curing by twisting at the edges of the mandrel and pulling it outwards. This specimen is then cut into required size for testing. The removed specimen will be having uneven edges. Thus it is cut for 1 cm length at both the ends for which the allowance is provided at the initial stages while cutting the fiber from the roller for each specimen. Also the specimen is grinded at the edges for proper surface finish.
itself around 29.67 mm. So we planned to join the test specimen with the machine holder with the help of a T-joint. For this purpose the specimen was drilled with 8 mm drill bit at a distance of 6 mm from both the ends. This T-joint comprises of two parts. One is a flat metal strip of 3 mm thickness, length 12 mm and width 2 mm with an 8 mm hole drilled at each of its ends. This strip has to be aligned parallel to the specimen axis where one end of this strip is inserted inside the work holder of the machine and the other end is penetrated inside the hollow cylindrical specimen and is aligned in such a manner that the axis of the drilled hole of the metal strip must be coaxial with the drilled hole in the test specimen. The second part of the T-joint is a metal rod of 8 mm diameter which has to be inserted in the lateral direction through all the aligned holes of both the specimen and the metal strip. In this same way the specimen is connected to the work holder of the machine with the help of T-joint on both sides. It should be noted that all the drilled holds are provided with suitable tolerances for perfect alignment and adjusted for perfect fastening before the start of the (twisting) experiment. The test specimen is perfectly aligned and hold in the machine holder with the help of the T-joint with tight grip. Both the Data Acquisition system and the Torsion Testing Machine are connected and activated. As the test specimen is fixed at one end it is rotated manually (Twisting action) at the other end with the help of a lever connected with the motor without electrically switching ON the motor. For each of the 10 rotations the corresponding Torque and the angle of twist values are noted down from the Digital Data Acquisition system. It should be noted that the frequency of rotation must be constant. This is continued until the specimen breaks by the twisting action. Then the break point value is retrieved from the Data Acquisition system. Then the graph is plotted between the torque value and the corresponding angle of twist to indicate the variation of twist with the angle of twist and the peak torque value. The twisting force can also be applied by switching ON the electrical motor. But if done so only the break point can be obtained but the graph cannot be plotted. 4. Result and discussion 4.1. Peak torque analysis From the above mentioned experimental results (Fig. 1) it could be concluded that the specimen with 45° glass fiber orientation has the maximum torque carrying capacity and the specimen with bidirectional glass fiber orientation has the minimum torque carrying capacity. The specimen with CSM glass fiber orientation has torque carrying capacity less than the specimen with 45° fiber orientation but
3.1. Torsion testing
PEAK TORQUE PEAK TORQUE[Nm]
Torsion tests twist a material or test component to a specified degree, with a specified force, or until the material fails in torsion. The twisting force of a torsion test is applied to the test sample by anchoring one end so that it cannot move or rotate and applying a moment to the other end so that the sample is rotated about its axis. The rotating moment may also be applied to both ends of the sample but the ends must be rotated in opposite directions. The forces and mechanics found in this test are similar to those found in a piece of string that has one end held in a hand and the other end twisted by the other. Since the specimen holder in the conventional torsion testing machine can hold only a rod of maximum diameter 12 mm or rectangular strip of width 12 mm we are in need of preparing additional arrangement for the holding purpose as the mean diameter of the specimen we fabricated is
100 50 PEAK TORQUE 0
UNI
45
CSM
BI
FIBER ORIENTATION Fig. 1. Peak torque Analysis.
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greater than the specimen with unidirectional glass fiber orientation. This tearing test is an unusual type of test which is performed to find the edge tearing resistance of the cylindrical specimen which is made of Glass fiber. The conventional tensile testing machine is employed to perform this tearing test. The basic intension of this test is to determine the maximum load this fiber specimen withstands before it tears of at edges after applying axial load by penetrating the support hook at the top and bottom of the specimen and pulling apart. The specimen we fabricated for the analysis is of 22 mm length. For hanging the specimen in the hooks of the tensile testing machine the specimen is drilled with a 8 mm drill bit at a distance of 6 mm from both the edges of the cylindrical specimen in the same manner as it is drilled for torsion test. The specimen is fixed in the machine with the help of the hooks at both the ends and it is tightened to the optimum level for applying the axial load. The value of load in the dial indicator is adjusted to zero. The axial load is applied at the bottom with the help of the lever provided in the machine. The value of load is noted down for the corresponding 0.1 mm increment in the axial deflection of the specimen. Both the axial deflection and the Load values are noted down until the specimen tears of at the edges. 4.2. Peak load analysis for tearing From the above mentioned experimental results (Fig. 2) it could be concluded that the specimen with 45° glass fiber orientation has the maximum capacity to resist tearing. It can able to withstand load greater than 2500 N. Since the machine we used can apply only load upto 2500 N, we cannot find the accurate value. The specimen with unidirectional glass fiber orientation can resist more tear load than the specimen with CSM fiberorientation. The specimen with bidirectional glass fiber orientation has the least capacity to withstand tear.
As mentioned earlier the one of the motto of the compression testing in this study is to compare the strengths of the cylindrical specimen among different aspect ratios. For this reason the original dimension (Length = 22 mm, Mean Diameter 29.67 mm) which could be taken as 100% is divided as 75%, 50%, 25% and thus 4 such specimens are prepared for each of the orientation types. Since we are also comparing the strengths among the 4 different types of fiber fabric orientations on the whole 16 such (4*4 = 16) GFRP hollow cylindrical specimens are prepared for the compression testing [15]. Thus all fabricated specimens which are of same length (22 mm) are cut according to the aspect ratios for before testing and their edges are surface grinded to achieve the plane end condition. After the performing the compression test by observing the deformation of the specimen it is found that the glass fiber hollow cylindrical specimen wont buckle in compression instead it deforms at the edge by enlarging itself in a flower pattern.
4.4. Peak load analysis for compression Among the unidirectional orientation glass fiber (TYPE-1) the specimen with aspect ratio 3.71 is having the ability to withstand the highest peak load (compressive) and the specimen with aspect ratio 7.41 is having the ability to withstand the lowest peak load (Fig. 3). The specimen with aspect ratio 1.85 withstands lesser peak load than that of 3.71 but the same specimen withstands greater peak load that than the specimen of aspect ratio 5.56. Among the unidirectional orientation glass fiber (TYPE-1) the specimen with aspect ratio 5.56 is having the highest cross head travel (compressive) for breaking and the specimen with aspect ratio 7.41 is having the lowest cross head travel (Fig. 4). The specimen with aspect ratio 1.85 has lesser cross head travel (CHT) than that of 5.56 but the same specimen has greater cross head travel (CHT) than the specimen of aspect ratio 3.71.
4.3. Compression testing
4.5. Cross head travel analysis for compression
Compression testing is a very common testing method that is used to establish the compressive force or crush resistance of a material and the ability of the material to recover after a specified compressive force is applied and even held over a defined period of time. The maximum stress a material can sustain over a period under a load (constant or progressive) is determined. The specimen is compressed and deformation at various loads is recorded. Compressive stress and strain are calculated and plotted as a stress– strain diagram which is used to determine elastic limit, proportional limit, yield point, yield strength and, for some materials, compressive strength.
Fig. 5 explains the comparison of unidirectional orientation with different aspect ratio among unidirectional orientation glass fiber (TYPE-1) the specimen with aspect ratio 5.56 is having the highest cross head travel (compressive) for breaking and the specimen with aspect ratio 7.41 is having the lowest cross head travel (CHT). The specimen with aspect ratio 1.85 has lesser cross head travel (CHT) than that of 5.56 but the same specimen has greater cross head travel (CHT) than the specimen of aspect ratio 3.71. Fig. 6 explains the comparison among various fiber orientations with aspect ratio-1.85. Among the glass fiber specimen of aspect ratio 1.85 unidirectional orientation glass fiber (TYPE-1) specimen
3000 2000 1000
PEAK LOAD
0 FIBER ORIENTATION Fig. 2. Peak Load analysis.
PEAK LOAD PEAK LOAD[KN]
PEAK LOAD[N]
PEAK LOAD 40 30
PEAK LOAD
20 10 0
7.41 5.56 3.71 1.85 L/D RATIO
Fig. 3. Comparison of unidirectional orientation with various aspect ratio.
Please cite this article as: S. Senthil Gavaskar and S. Madhu, Torsional and compression properties of cylindrical glass fiber reinforced polymer composite, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.12.024
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COMPRESSIVE STRENGTH
40 20
PEAK LOAD
0
UNI 45 CSM BI FIBER ORIENTATION
200
L/D RATIO
PEAK LOAD[KN]
PEAK LOAD
100 0
COMPRESSIVE STRENGTH 7.41 5.56 3.71 1.85
COMPRESSIVE STRENGTH[N/sq.mm] Fig. 4. Comparison of peak load for different fiber orientation.
CROSS HEAD TRAVEL
CROSS HEAD TRAVEL [mm]
Fig. 5. Comparison of unidirectional orientation with various aspect ratio.
CROSS HEAD TRAVEL
150 100
COMPRESSIVE STRENGTH
50 0
UNI 45 CSM BI
L/D RATIO
COMPRESSIVE STRENGTH COMPRESSIVE STRENGTH[N/sq.mm]
1.85
3.71
CROSS HEAD TRAVEL 5.56
4 3 2 1 0
7.41
CROSS HEAD TRAVEL [mm]
Fig. 7. Comparison of unidirectional orientation with various aspect ratio.
FIBER ORIENTATION
Fig. 8. Comparison among various fiber orientations with aspect ratio-1.85.
12 10 8
CROSS HEAD TRAVEL
6 4 2 0
UNI 45 CSM BI FIBER ORIENTATION
has greater compressive strength that than the specimen of aspect ratio 1.85 [17]. Among the glass fiber specimen of aspect ratio 1.85chopped strand mat layered glass fiber (TYPE-2) specimen is having the highest compressive strength (compressive) and the specimen with bidirectional orientation (TYPE-3) is having the lowest compressive strength (Fig. 8). The specimen with unidirectional orientation (TYPE-1) is having lesser compressive strength than the CSM (TYPE-2) but the same specimen has greater compressive strength than the 45° cross ply orientation glass fiber (TYPE-4) specimen.
Fig. 6. Comparison among various fiber orientations with aspect ratio-1.85.
5. Conclusions is having the highest CHT (compressive) and the specimen with bidirectional orientation (TYPE-3) is having the least CHT. The specimen with chopped strand mat layered glass fiber (TYPE-2) is having lesser CHT than the unidirectional (TYPE-1) specimen but the same specimen has greater CHT than the 45° cross ply orientation glass fiber (TYPE-4) specimen [16].
4.6. Compressive strength analysis Fig. 7 indicates the comparison of compressive strength. Among the unidirectional orientation glass fiber (TYPE-1) the specimen with aspect ratio 3.71 is having the highest compressive strength and the specimen with aspect ratio 7.41 is having the lowest compressive strength. The specimen with aspect ratio 5.56 has lesser compressive strength than that of 3.71 but the same specimen
From the torsion test performed and the comparative analysis conducted among the various fiber orientations incorporated glass fiber cylindrical specimen it could be concluded that the TYPE-4 specimen is having the highest torsional strength in comparison with other types. While the TYPE-3 specimen is having the least torsion strength. Thus the TYPE-4 specimen could be highly suggested for the low power transmitting torsional applications compared with other glass fiber specimen. From the tearing test performed with the help of the tensile testing machine and the comparative analysis conducted among the various fiber orientations incorporated glass fiber cylindrical specimen it could be concluded that the TYPE-4 specimen has tearing resistance in the surface more than 2500 N. But the actual tearing point is unfound. Whereas the TYPE-3 specimen has the least tearing resistance compared with other types. From the compression tests performed and the comparative analysis conducted among the various fiber orientations incorporated glass fiber cylindrical specimen it could
Please cite this article as: S. Senthil Gavaskar and S. Madhu, Torsional and compression properties of cylindrical glass fiber reinforced polymer composite, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.12.024
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be concluded that TYPE-1 and TYPE-2 specimens are having comparatively higher compressive strength than the TYPE-3 and TYPE-4 specimens. From the compression tests performed and the comparative analysis conducted among the various aspect ratios the glass fiber cylindrical specimen having the aspect ratio 7.41 is having the least compressive strength compared with other specimens of aspect ratios 5.56, 3.71 and 1.85. Thus the glass fiber hollow cylindrical fabricated with unidirectional orientation and chopped strand mat layers having lesser aspect ratios could be suggested for high axial compression loading applications. Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. References [1] T.P. Sathishkumar, S. Satheeshkumar, Naveen, Glass fiber-reinforced polymer composites - A review, J. Reinf. Plast. Compos. 33 (2014) 1258. [2] M.S. Ahmadi M.S. Johari M. Sadighi An experimental study on mechanical properties of GFRP braid pultruded composite rods Exp. Polym. Lett. Esfandeh 3 2009 No.9 [3] K. Ramesh Babu, V. Jayakumar, G. Bharathiraja, S. Madhu, Experimental investigation of fish scale reinforced polymer composite, Mater. Today Proc. (2019), https://doi.org/10.1016/j.matpr.2019.07.594. [4] P. Kumaran, S. Mohanamurugan, S. Madhu, R. Vijay, D. Lenin Singaravelu, A. Vinod, M.R. Sanjay, Suchart Siengchin, Investigation on thermo-mechanical characteristics of treated / untreated portunus sanguinolentus shell powder based jute fabrics reinforced epoxy composites, J. Ind. Text. (2019), https://doi. org/10.1177/1528083719832851. [5] P. Sangeetha, R. Sumathi, Behavior of glass fiber wrapped concrete columns under uniaxial compression, Int. J. Adv. Eng. Technol. 1 (1) (2010) 74–83.
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Please cite this article as: S. Senthil Gavaskar and S. Madhu, Torsional and compression properties of cylindrical glass fiber reinforced polymer composite, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.12.024