Hybrid FRP Research Articles

Effects of different interface conditions on energy absorption characteristics of Al/carbon fiber reinforced polymer hybrid structures for multiple loading conditions

AbstractThe treatment of carbon fiber reinforced polymer (CFRP)–metal bond interface is very important for the practical application of CFRP‐reinforced metal structures in automobile, aviation, and other transportation vehicles. In this article, the effects of different interface connection conditions on the failure mode and energy absorption of hybrid tubes were studied by experimental and simulation methods. For this purpose, the two aspects metal surface treatment (sandblasting) and connection mode (socket, co‐curing, and secondary bonding) were used for adhesive joining. By observing the force–displacement curve, the energy absorption capacity of the hybrid tube under different interface connection conditions was quantified, and the performance was evaluated. The calculation results show that the interfacial connection conditions have different effects on the crashworthiness of the hybrid tube under different loading conditions. Among them, for axial crushing and transverse bending loads, the energy absorption characteristics of the hybrid tube can be effectively improved by sandblasting and cementing. Under the action of radial compression, although the roughness of the interface is increased by sandblasting, the energy absorption capacity is reduced rather than enhanced. In order to reveal the mechanism and make parameterized definitions of the interface characteristics, so as to effectively predict the finite element model is especially necessary. With the improvement of interface bond strength, its bearing limit distribution area also increases, and the corresponding deformation is also large, which eventually leads to more energy absorption under axial crushing and transverse bending loads. The increase in the interface connection strength has little effect on its crashworthiness under radial pressure.

Abrasive wear and dynamic–mechanical behavior of marble dust filled bagasse fiber reinforced hybrid polymer composites

AbstractThe present study investigated the influence of waste materials on physico‐mechanical, dynamic mechanical, and abrasive wear behavior of polymer composites. The composites were manufactured by varying the waste bagasse fiber (2.5, 5, 7.5, and 10 wt%) in fixed marble dust (15 wt%) filled epoxy resin. The void content of the composite found to decrease, whereas density, impact energy, and flexural strength were found to increase with the increase of waste bagasse fiber loading. The hardness and tensile strength were first increased, and after attaining highest values for 7.5 wt% fiber content, both decreased with another fiber loading. Damping properties such as storage modulus, loss modulus, and damping factor were evaluated utilizing dynamic mechanical analyzer. Results showed that the composites with 10 wt% waste bagasse fiber loading exhibited highest viscoelastic properties. Moreover, the dry sand abrasive wear behavior of fabricated composites was designed to study the impact of fiber loading, sliding distance, and load using the Taguchi method. The analysis reveals that the sliding distance contributes the most toward abrasive wear of the composites, with a contribution of 58.70%. 7.5 wt% waste bagasse fiber, 400 m sliding distance, and 5 N load resulted in a most wear‐resistant combination. Finally, the abraded composite surfaces were examined using scanning electron microscopy to study the possible wear mechanisms.

Experimental Study of Tensile, Flexural and Impact Strength of Basalt/Glass FRP Hybrid Composite with Carbon Black

Metal components have been replaced by composite ones in the modern engineering aspects due to various reasons such as strength to weight ratio, ease of manufacturing as well as aesthetic value. Currently majority of composites are made by using synthetic fibres which again is a concern for the environment because of non-biodegradability issues with synthetic fibres. Hence natural fibres appear to be an alternative option to synthetic fibres. But the major drawback would be the strength of the fibres and its behaviour with its surrounding environment hence hybrid appears to be the possible solution in order to balance both the constraints of strength and environment. This study describes the mechanical properties of a hybrid composite comprising of Basalt fibre and Glass fibre developed by using hand lay-up techniques. Woven Basalt fibres and Glass fibres were used for fabricating the hybrid composites, carbon black as nano fillers, vinyl ester resin as matrix with different fibre stacking sequences. The result shows that the reinforcement of woven Basalt and Glass fibres hybrid composites with carbon black has a significant influence on the mechanical properties of the composites. The stacking sequence also has an effect on the strength of the specimen. The tensile strength of hybrid composite having stacking sequence B/3G/B/3G/B increase by 15.49 % with the addition of 9% carbon black whereas the stacking sequence G/3B/G/3B/G has a decrease in tensile strength by 21.77%. The flexural strength of the hybrid B/3G/B/3G/B decrease by 72.5% with the addition of carbon black while the hybrid G/3B/G/3B/G shows an increase by 32.38%. The highest impact strength is of basalt with 6% composite.

New hybrid basalt/E-glass FRP jacketing for enhanced confinement of recycled aggregate concrete with clay brick aggregate

Recycled aggregate concrete (RAC) is more sustainable, eco-friendly, and cost-effective as compared to natural aggregate concrete (NAC). Among recycled aggregates (RAs), clay brick aggregate (CBA) has the potential of being the most widely used RAs because of the considerable amount of clay brick waste generated in many countries. The compressive behavior and mechanical properties of RAC with CBA are highly influenced by the mechanical properties of bricks. The stiffness and compressive strength of RAC with CBA are reported marginally lower than the natural aggregate concrete (NAC). In the past, different types of fiber reinforced polymer (FRP) composites such as carbon FRP, glass FRP, and aramid FRP have been investigated to enhance the strength and stiffness of the RAC with CBA. However, the behavior of hybrid FRP confined RAC with CBA is not yet clear. In this study, the performance of a new, low-cost and high-performance hybrid composite to enhance the strength and stiffness of the RAC with CBA is investigated. Hybrid composite is developed by using natural Basalt fiber and E-glass fibers (Chopped Strand Mat) along with the use of high-performance polyester resin. Three types of bricks (having different strength and water absorption) were used to produce CBA. Other research parameters included were the strength of RAC with CBA and the number of layers of hybrid basalt/E-glass fiber reinforced polymer (BE-FRP) composite. A total number of 36 concrete cylinders (12 un-confined and 24 confined with BE-FRP) were tested under pure axial compressions. The results indicate that the BE-FRP composites are highly suitable to enhance strength, stiffness, and ductility of the RAC with CBA. Also, there was found a significant increase in strength and ductility with an increase in the confinement level. In the end, the efficiency of existing strength and stain models was assessed to predict the ultimate strength and strain of the BE-FRP confined RAC with BAC.

Fabrication and Testing of Hybrid Laminate reinforced with Natural Fibre

This present work discussed about fabrication and testing of hybrid laminate reinforced with natural fibres, in general engineering materials with high-performance are used in various manufacturing methods from different resources has been investigated by many researchers across the world. The raw materials which are taken from renewable sources are environmentally good ¬ cause any kind of health issues, now a day’s most of natural fibre based hybrid composites are used different areas like automobile companies and aircraft industries for manufacturing their inside and outside parts of the mechanical bodies and it’s not affected environment, the exact reason behind this is a natural fibre, because of its easy availability & low cost. The hybrid composites are fabricated by using the natural fibre reinforcements as they exhibit their low density, low cost as well as exhibit better mechanical properties. The present work includes the manufacturing of natural fibre (wool and jute) reinforced polymer composites are discussed and this natural fibre reinforced hybrid polymer composite is tested and compared with the glass fibre epoxy polymer composite. the testing performed are flexural and compression and different strengths are collected finally and it is concluded that compared with the glass fibre polymer composite, hybrid laminate (natural fibres) are in good condition in terms of strength and their application are also brought into consideration.

Structural Behavior of Self-Compacted Reinforced Concrete Beams Strengthed with HYBRID FRP Systems.(Dept.C)

Self-compacted concrete (SCC) is a recent application of reinforced concrete. Some properties of this type of concrete are recently studied. In this work the ductility of self compacted reinforced concrete beams was investigated experimentally. Where nine reinforced concrete beam models 10x20x170 cm were cast and tested till failure. The parameters taken into consideration were the methods of strengthening using FRP and steel systems. Where eight different strengthened methods were used including glass fiber reinforced polyester, carbon fiber wrap reinforced polyester and galvanized steel plates. Recorded measurements including cracking loads, ultimate loads, deflection, rotation and modes of failure. The experimental results show that the self-compacted concrete have a good mechanical properties rather than normal strength concrete. The results indicated that the FRP strengthened systems enhancing ductility behavior of self- compacted concrete beams, increasing cracking loads, ultimate loads, cracking distributions and control modes of failure. Comparison between the experimental results and the theoretical ones using ACI 440-2R-02. was performed and discussed.

Adhesively bonded joints of jute, glass and hybrid jute/glass fibre-reinforced polymer composites for automotive industry

Natural fibre-reinforced composites have attracted a great deal of attention by the automotive industry mainly due to their sustainable characteristics and low cost. The use of sustainable composites is expected to continuously increase in this area as the cost and weight of vehicles could be partially reduced by replacing glass fibre composites and aluminium with natural fibre composites. Adhesive bonding is the preferred joining method for composites and is increasingly used in the automotive industry. However, the literature on natural fibre reinforced polymer composite adhesive joints is scarce and needs further investigation. The main objective of this study was to investigate experimentally adhesively bonded joints made of natural, synthetic and interlaminar hybrid fibre-reinforced polymer composites. The effect of the number of the interlaminar synthetic layers required in order to match the bonded joint efficiency of a fully synthetic GFRP bonded joint was studied. It was found that the failure load of the hybrid jute/glass adherend joints increased by increasing the number of external synthetic layers (i.e. the failure load of hybrid 3-layer joint increased by 28.6% compared to hybrid 2-layer joint) and reached the pure synthetic adherends joints efficiency due to the optimum compromise between the adherend material property (i.e. stiffness and strength) and a diminished bondline peel stress state.

Flexural performance of Hybrid Fiber Reinforced Polymer Concrete using PVA fiber

This paper present the experimental result of flexural behavior of Hybrid Fiber Reinforced Polymer (HFRP) concrete beams reinforced with Glass Fiber Reinforced Polymer (GFRP) rebars and steel bars. This experiment is conducted with the aim of replacing steel reinforcement with GFRP rebars to reduce the risk of corrosion of steel in concrete structures. The data presented in this study is obtained by conducting flexural test experiment on four beams of HFRP beams with various PVA fibre dosage of 0%, 0.25% and 0.5% and one Pure FRP beam. Fly ash is added by 25% in the mix as a mineral admixture to control the shrinkage cracks. The test result showed that by addition of PVA fibre in HFRP concrete enhance the mechanical properties of beam like deflections, ductility, load carrying capacity and flexural capacity. The optimum dosage of PVA fibre is 0.25%. which improve flexural strength by 200% and 31.1% and ductility increased by 112.2% and 55.12% as compared with Pure FRP beam and HFRP beam without PVA fibre.

Compressive Properties of BFRP and HFRP Bars

Durability of steel reinforced structures is one of the leading problems in construction field nowadays. Currently many studies are focused on the possibility of steel reinforcement replacement in concrete structures with a non-corrosive reinforcement, such as FRP (Fiber Reinforced Polymer) reinforcement. This paper presents and compare the results of compression testing of Basalt (BFRP) and a newly developed type of Hybrid FRP (HFRP) bars. The program examined 30 HFRP bars and 30 BFRP bars with a nominal diameter of 8mm and unbraced free-length varying from 50 to 220 mm. Compressive buckling load strength decreased as free length increased, and the modulus of elasticity under compression for diverse unbraced lengths bars slightly differed, but its value was similar to the modulus of elasticity at tensile. In addition, the test results showed that the ultimate compressive strength of non-buckled HFRP bars as a result of axial compression is about 46% of the ultimate strength. The relationships between the compressive buckling load strength and the unbraced length as well as the optimal unbraced length of the bars were determined. Current research is aiming to contribute the optimization of the transverse reinforcement design and the development of standard regulations in the area of elements with such compressed reinforcement.

Effect of glass fibre hybridization on the water absorption and thickness of alkali treated kenaf-epoxy composites

Abstract Natural and synthetic fibre reinforced hybrid polymer composites have attracted significant attention due to their combined benefits of biodegradability and strength. Kenaf fibres have the potential to replace synthetic fibres in polymer composites due to their excellent mechanical properties. However, their use for high strength and water resistance applications are not found suitable due to their hydrophilic nature. The main aim of this study is to reduce the water absorption capacity of kenaf fibre composites through alkali treatment and glass fibre hybridization. The continuous fibre, alkali treated, unidirectional kenaf-glass–epoxy hybrid composites (K untreated, K Treated, G/K/G, G/K/G/K/G, G) were prepared by the hand lay-up method and their water absorption and thickness swelling behaviour studied. Thereafter the diffusion properties like diffusion coefficient (Dc), corrected diffusion coefficient (Dcc), sorption coefficient (Sc) and permeability coefficient (Pc) of above composites were also calculated. The results show that alkali treated hybrid composites with stacking sequence G/K/G/K/G exhibited the lowest water absorption and thickness swelling capacity in comparison to kenaf fibre composites. The alkali treated kenaf fibre composites reduced the water absorption and thickness swelling capacity by 23% and 13% respectively compared to untreated kenaf fibre composites while the glass fibre hybridization further reduced the water uptake and thickness swelling by 35% and 32% respectively as compared to alkali treated kenaf fibre composites.

Experimental investigation on mechanical properties of flax/banana/ industrial waste tea leaf fiber reinforced hybrid polymer composites

In the present research, work focus has been given to determine mechanical properties of biodegradable industrial waste tea leaf fiber (WTLF), banana and flax fiber reinforced hybrid polymer composites using experimental approach. Banana fibers and WTLF were alkali treated with 5% NaOH solution. The hybrid composite laminates were manufactured using manually operated compression moulding machine with the volume fraction of 40:60 (Fiber: Matrix). As per ASTM standard, the mechanical characteristics were studied. The experimental results showed excellent mechanical characteristics for 5 wt% WTLF and 25- wt% banana fiber reinforced hybrid composites. The fractography analysis of untreated and alkali treated composites were examined using Scanning Electron Microscopy (SEM) and results revealed that superior mechanical bonding existed between fiber and polymer in case of alkali treated fiber composites.

Investigation of moisture absorption and mechanical properties of natural fibre reinforced polymer hybrid composite

The significance of herbal fibre bolstered composites is rapidly developing both in phrases of engineering utility and studies area. These herbal fibres are completely renewable, environmental pleasant, high particular energy, non-abrasive, low fee, biodegradability. Natural fibre powered composites update metals due to their insubstantial, excessive strength to weight ratio, non-corrosive nature and rigidity. However poor interfacial adhesion among fibre and matrix, low melting point and absence of moisture resistance has constrained the usage of herbal fibre. Hybridization allows to tweak the residences of composites as in line with specified requirements and to get the excellent performance. The search is to expand a new magnificence of cloth the usage of green fibre extracted from environmental which is to be a better opportunity for present inexperienced composites. In the prevailing studies, sisal (S) and pineapple leaf fibre (PALF) are decided on because of their eco-friendly nature. Initially, optimal fibre length and weight percent have been decided. To enhance the mechanical homes, pineapple fibre became hybridized with sisal fibre. This observes exhibited that addition of sisal fibre in pineapple/polyester composites of as much as 50% through weight results in growing the mechanical residences and reducing the moisture absorption assets. The tensile, flexural, effect and water absorption exams had been achieved the usage of pineapple/sisal polyester composite fabric.

Drill hole surface characterisation of hybrid FRP laminates through statistical analysis

ABSTRACT As it is known that the hybrid Fibre Reinforced Polymer (FRP) composite laminate is a recently evolved class of structural material. Hence, the present work deals with secondary processing ability like hole drilling on hard to machine FRP laminate. The influence of drilling attributes on the delamination factor and surface roughness contours are studied for a high thickness hybrid (carbon/glass FRP) laminates. Here, the experimentation was performed utilising Taguchi’s L27 design of experiments array. Later, on post-drilling, the predominant and optimum variables were studied through taguchi and variance analysis to highlight their contribution on the response functions. Taguchi results indicate that the combination of the 90՞tungsten carbide tool, speed of 800 rpm, and rate of feed 50 mm/min gives the best performance concerning the delamination. Also, it was observed that the combination of the 118՞tungsten carbide tool, cutting speed of 900 rpm and the rate of feed 60 mm/min give the best performance concerning surface roughness. Whereas, as per ANOVA, the highest percentage contribution factor was concerned to a tool material followed by other factors and analysed data lie with the confidence level of 95%. The work also indicates that tungsten carbide tool yield better results compared to high-speed steel tool. Further, fibre morphology has been studied, which indicates optimal structure with minimal damage.

Evaluation of tensile properties of hybrid kevlar-glass reinforced epoxy composite for multi holes configuration

Abstract Most modern structures are comprised of synthetic composites with more number of cut outs. For the design of synthetic composite with varying shapes with different sized cut-outs are often used in engineering structures. The effects of stress concentration factor and tensile behaviour has to be thoroughly investigated for providing better design aids to be utilized by design engineers. The present paper focuses on the tensile behaviour of the Kevlar and glass fiber reinforced hybrid polymer composite by varying size and position of the cut outs. The test specimens are prepared according to the ASTM standard D3039. The composite laminates are prepared by traditional hand layup method. The overall dimension of plates were 25 mm*250 mm (width*length) and with the gauge length was 110 mm. These plates were drilled with the circular holes of 8 mm and 5 mm. The larger hole of diameter 8 mm was drilled at centre of all the specimens and smaller holes of diameter 5 mm was drilled on either sides of 8 mm hole. The pitch for smaller 5 mm holes were increased in the order of 0, 15, 20, 25 and 30 mm respectively. The specimen with smaller holes at 25 mm pitch showed highest allowable stress of 97.22 MPa. The experimental results were compared to find the optimum position for placing the holes. This research also intends to find out if there exists any relationship between the pitch, diameter of smaller and larger holes present in the specimen.

Tensile and Shear Testing of Basalt Fiber Reinforced Polymer (BFRP) and Hybrid Basalt/Carbon Fiber Reinforced Polymer (HFRP) Bars.

The use of sustainable materials is a challenging issue for the construction industry; thus, Fiber Reinforced Polymers (FRP) is of interest to civil and structural engineers for their lightweight and high-strength properties. The paper describes the results of tensile and shear strength testing of Basalt FRP (BFRP) and Hybrid FRP (HFRP) bars. The combination of carbon fibers and basalt fibers leads to a more cost-efficient alternative to Carbon FRP (CFRP) and a more sustainable alternative to BFRP. The bars were subjected to both tensile and shear strength testing in order to investigate their structural behavior and find a correlation between the results. The results of the tests done on BFRP and HFRP bars showed that the mechanical properties of BFRP bars were lower than for HFRP bars. The maximum tensile strength obtained for a BFRP bar with a diameter of 10 mm was equal to approximately 1150 MPa, whereas for HFRP bars with a diameter of 8 mm, it was higher, approximately 1280 MPa. Additionally, better results were obtained for HFRP bars during shear testing; the average maximum shear stress was equal to 214 MPa, which was approximately 22% higher than the average maximum shear stress obtained for BFRP bars. However, HFRP bars exhibited the lowest shear strain of 57% that of BFRP bars. This confirms the effectiveness of using HFRP bars as a replacement for less rigid BFRP bars. It is worth mentioning that after obtaining these results, shear testing can be performed instead of tensile testing for future studies, which is less complicated and takes less time to prepare than tensile testing.

Enhanced Infrared Sparse Pattern Extraction and Usage for Impact Evaluation of Basalt-Carbon Hybrid Composites by Pulsed Thermography.

Nowadays, infrared thermography, as a widely used non-destructive testing method, is increasingly studied for impact evaluation of composite structures. Sparse pattern extraction is attracting increasing attention as an advanced post-processing method. In this paper, an enhanced sparse pattern extraction framework is presented for thermographic sequence processing and defect detection. This framework adapts cropping operator and typical component extraction as a preprocessing step to reduce the dimensions of raw data and applies sparse pattern extraction algorithms to enhance the contrast on the defect area. Different cases are studied involving several defects in four basalt-carbon hybrid fiber-reinforced polymer composite laminates. Finally, comparative analysis with intensity distribution is carried out to verify the effectiveness of contrast enhancement using this framework.

Effect of brachyura shell particles on glass fibre reinforced epoxy polymer composite

Abstract Bio filler E-glass fiber reinforced hybrid polymer composites having massive demand in the present scenario due to their excellent mechanical properties and also increasing of environmental awareness. Bio fillers like crab shell powder, sawdust, prawn shell powder, rice husk are the best substituent for glass, carbon, ceramic, synthetic fillers. Every year, 8.5 million tons of crab & shrimp shell waste generated in India. To manage this waste it was used as a filler material along with the E-glass fiber with epoxy. Polymer composite due to crab shell chemical similarity with CaCO3.In the present study crab shell powder with various fractions (0%, 3%, 5%, and 7%) & e-glass fiber was composed to prepared hybrid polymer composites by adopting wet hand lay-up process, followed by 24 hr curing at room temperature. Crab shell powder reinforced hybrid polymer composites density, SEM studies and mechanical properties (hardness, tensile strength, flexural strength and impact strength) were determined as per ASTM standards. The density of the hybrid polymer composites increased with increasing the weight fraction of the crab shell powder. The higher mechanical properties were obtained at 5% crab shell powder filler composite.

A simplified method for steady state and transient state thermal analysis of hybrid steel and FRP RC beams at fire

This paper suggests and validates a simplified analytical method for thermal steady state and transient state analysis of hybrid steel and FRP reinforced concrete beams exposed to elevated temperature induced by fire. The proposed method predicts the flexural resistance of concrete beams based on strain compatibility and force equilibrium of the beam section under pure bending moment taking into account the deterioration in mechanical properties of concrete, steel and FRP bars due to the rise of temperature. The accuracy of the suggested method was ascertained against the corresponding experimental tests results. Validation results, in terms of load-displacement curves; displacement- time histories and failure modes, have shown the reliability and feasibility of the suggested analytical method. Afterward, the verified method was implemented in investigating the effect of important parameters on the response and failure of hybrid steel and FRP reinforced concrete beams under elevated temperature such as concrete cover, reinforcement ratio, and heating rate. The results extracted from the parametric study have come up with interesting conclusions which may be utilized in the design of thermally exposed concrete beams with hybrid reinforcement.

Development of a new analytical framework for deflection analysis of un-symmetric hybrid FRP laminates with arbitrary ply arrangement and MWCNT reinforcement

This research explores the influence of various parameters on the cured shape of hybrid fiber reinforced polymer (FRP) laminates. A new analytical framework based on micromechanics models is developed in MATLAB containing all formulations for deflection analysis of laminated composite structures with fibrous and multi-walled carbon nanotubes (MWCNTs) reinforcements. After verifying the reliability and accuracy of represented computational model, we studied the influence of mold radius on the cured shape of laminates with cross-ply and non-cross-ply arrangements. The effects associated with shear strain deformation term are similarly examined for both ply arrangements. Next, the curvature response of several arbitrary configurations as well as reinforcing with different MWCNT percentages are studied. Finally, some points are suggested regarding the optimal design of hybrid FRP composite structures considering curvature response.

Effects of nano-sized silica particles on the off-axis creep performance of unidirectional fiber-reinforced polymer hybrid composites

A multi-step homogenization approach is presented to predict the off-axis creep response of hybrid polymer matrix composites (HPMCs) reinforced with unidirectional carbon fibers and silica nanoparticles. The first step deals with evaluating the viscoelastic properties of silica nanoparticle-polymer nanocomposite using the Mori-Tanaka micromechanical model. Two essential features affecting the behavior, including silica nanoparticle agglomeration and interphase region generated due to the interaction between the nanoparticle and polymer are taken into account. In the second step, the off-axis viscoelastic behavior of HPMCs is extracted from the homogenized nanocomposite and carbon fiber properties using a unit cell-based micromechanical model. Some comparative studies between the predictions and available experiment are directed to verify the homogenization process. All the model predictions are in good agreement with the experimental data. The results indicate that with increasing the fiber off-axis angle from 0° to 90°, the presence of silica nanoparticles leads to a reduction in the HPMC creep compliance. Also, the proposed multi-step homogenization approach is applied to investigate the effects of volume fraction, size and agglomeration degree of silica nanoparticles; thickness and material properties of the interphase region; and off-axis angle and volume fraction of the carbon fiber on the HPMC creep response.