Intraply Hybrid Composites Research Articles

Investigating the tensile properties of 3D printed semi-woven intraply hybrid composites reinforced with carbon/glass continuous fibres

In this study the mechanical performance of 3D printed intraply hybrid semi-woven composites was investigated. The hybrid composites were fabricated from two types of tow-preg filaments that consist of either carbon or glass fibres impregnated with polyamide, referred to as low elongation (LE) and high elongation (HE) materials respectively. The effect of two printing parameters, weave type and the LE material ratio, were investigated using fifteen unique laminates. The ultimate strain of the hybrid laminates was dependent on the LE material ratio with a transition point at ∼50%. Analytical and FE models were used to predict laminate strength and modulus. In general, the FE model underpredicted the experimental data and the analytical models showed good correlation with experimental observations. The validated analytical model can be used to design hybrid semi-woven laminates to produce a targeted modulus and strength through appropriate selection of weave type and LE material ratio.

Effect of various weaving architectures on mechanical, vibration and acoustic behavior of Kevlar-Hemp intra-ply hybrid composites

Due to the benefits of including high stiffness, low density, low cost, ecologically benign nature and abundant availability, natural fibers are employed as reinforcement in composites. These fibers however have a few shortcomings, including poor moisture resistance and incompatibility with most matrices. Therefore, the goal of this research is to combine the benefits of natural fiber (hemp) with synthetic fiber (kevlar) to develop a hybrid composite. Hemp and Kevlar yarns were handloomed to form fabrics with different architectures such as plain, twill and basket. These hybrid fiber epoxy composites were fabricated using compression molding and the samples were subjected to mechanical testing, free vibration and acoustic emission characteristics. Hemp and Kevlar fiber composites were also fabricated for comparison purpose. The results revealed that the twill and basket weave intra ply hybrid composites exhibited the better mechanical properties when compared with the plain weave hybrids. Whereas, the free vibration results showed that the all the hybrids exhibited better performance that the mono-fiber composites. Acoustic behavior of the basket weave hybrid was found to have the highest sound transmission loss value of 13.7 dB in the higher frequency range. On the other hand, the hemp-epoxy composites exhibited the highest sound transmission level of 6.3 dB in the lower frequency range.

Mechanical properties of interply and intraply hybrid laminates based on jute-glass/epoxy composites

Currently, hybridization of natural-synthetic fibers within a polymeric matrix has received wide attention owing to its promising properties. This study investigated the mechanical properties of interply and intraply hybrid jute (J)-glass (G) fiber/epoxy composites. The mechanical properties (i.e., tensile, flexural, and impact) of the pure jute, pure glass, and their hybrid composites were evaluated. The prepared composite samples consisted of five plies of woven fabrics. Interply hybrid composites comprised three layering sequences: G3JG, GJGJG, and 2GJ2G. Intraply hybrid composites of similar co-woven plies were fabricated by either the alternative replacement of a single glass yarn with a single jute yarn (G1J1) or two jute yarns (G1J2). The results showed that increasing the glass fraction in the interply hybrid composites improved their tensile properties. The two intraply hybrid composites provided almost similar tensile moduli, while the tensile strength of the G1J1 samples was approximately 41% higher than that of the G1J2 counterparts. The maximum flexural properties were provided by 2GJ2G composites, followed by GJGJG, and they were interestingly higher than those of pure glass composites. The G1J1 intraply hybrid composites offered a higher flexural strength and a lower flexural modulus than those provided by the pure glass composites. Compared to the pure glass composites, the impact strengths of the 2GJ2G and GJGJG samples decreased by 4% and 16%, respectively. In summary, the GJGJG hybrid composites exhibited the highest specific tensile, flexural, and impact properties compared to the other hybrid composites.

An experimental study on RC beams shear-strengthened with Intraply Hybrid U-Jackets Composites monitored by digital image correlation (DIC)

Reinforced concrete (RC) beams are commonly strengthened using steel stirrups, but these materials have limitations such as added weight and susceptibility to corrosion. Fiber-reinforced polymers (FRPs) offer a promising alternative to steel stirrups with high mechanical performance, low density, and resistance to corrosion and chemicals. In particular, Intraply Hybrid Composites (IRCs), which comprise multiple fibers oriented in different directions within a single matrix, have recently gained attention in the construction industry. Cakir et al. [1] investigated the use of three types of IRCs (Aramid-Carbon (AC), Glass-Aramid (GA), and Carbon-Glass (CG)) for strengthening 2-meter-long RC beams (the ratio of shear span (a) to effective depth (d) equals 3 (a/d = 3)) against shear fractures. In this study, the effects of these IRCs on the shear strength of 1.5-meter-long RC beams (a/d = 2) without transverse reinforcement were examined. In this scope, four-point bending tests were conducted on the beams after U-shaped IRC strengthening, and the impact of IRCs on shear strength was evaluated using both digital image correlation and classical measurement equipment such as strain gauges and linear variable differential transducers. The maximum load measured in RC1.5 was 194.50 kN, while the ultimate load capacity reached 265 kN in AC1.5, 246 kN in GA1.5, and 229 kN in CG1.5 after strengthening, representing increases of 36%, 26%, and 18%, respectively, compared to RC1.5. Additionally, the maximum mid-span deflections were determined as 30.40 mm, 16.10 mm, 22.20 mm, and 36.40 mm for RC1.5, AC1.5, GA1.5, and CG1.5, respectively. Moreover, the experimental results were compared with the predictions obtained from the international codes. It should be noted that the failure modes of RC beams are directly affected by the type of IRCs used, highlighting the significant contribution these materials can make to the structural behavior of RC beams.

Assessment of nanoclay impact on buckling response of carbon/Kevlar hybrid composites

AbstractThis study investigates the effects of nanoclay (NC) particles on the buckling behavior of carbon/Kevlar intraply hybrid composites. The laminates containing various amounts of NC particles (0.5%, 1%, 1.5%, 2%, and 3% by weight) were manufactured using hand layup stacking followed by vacuum bag molding process. The prepared samples were subjected to axial and lateral compressive loads under fixed‐fixed and fixed‐free boundary conditions, respectively, and the relevant critical buckling loads were determined. Furthermore, the failure modes were examined via microscopic views taken from the damaged areas on the samples to fully understand the influences of NC particles on buckling characteristics. The findings demonstrated that the buckling behaviors of the samples were significantly affected by the introduction of NC particles. Compared with the composite samples without any NC particles, the composite samples with 1 wt% NC particles showed an increase of 21.12% and 25.33% in the axial and lateral critical buckling loads, respectively. However, the inclusion of NC particles with an amount that higher than 1 wt% showed a decreasing trend in terms of critical loads for both buckling loadings, which can be viewed as a measure of load‐bearing capability. Moreover, the samples filled with 3 wt% NC particles exhibited a decrement on critical loads compared with those of samples without any NC particle filler. With the help of microscopic views, the failure modes were detected as matrix fragmentation and delamination for both buckling loadings.

High strain rate damage sensing in intra-ply hybrid composites under dynamic shear loading

An experimental study is performed to investigate the damage sensing in intra-ply glass/carbon hybrid composites at high strain rate shear loading conditions. A unique four circumferential probe measuring technique is used to measure the electrical response during dynamic shear loading. Double-notch specimen geometry is considered to investigate the electrical and shear behavior of composites. A split Hopkinson pressure bar apparatus in conjunction with high-speed imaging is used to conduct dynamic shear characterization. Glass fiber (GF) reinforced composites demonstrated elastic buckling and had a delayed crack initiation. However, no buckling is observed for intra-ply hybrid composites and the crack initiated much earlier than the GF composite. Orientation of glass and carbon fibers in intra-ply composites considerably influenced the dynamic shear strength and piezo-resistance sensitivity. Among the four intra-ply layups, alternating (+45o/-45o) layup of intra-ply composites show a high resistance sensitivity, and it improved significantly with an increasing strain rate.

The effect of fiber orientation and stacking sequence on carbon/E‐glass/epoxy intraply hybrid composites under dynamic loading conditions

AbstractThis study investigated the dynamic mechanical properties of hybrid intraply carbon/E‐glass epoxy composites with different orientations and stacking sequences under different loading conditions with increasing temperature. A neat epoxy and five various hybrid composites such as Carbon (0°)/E‐glass (90°), Carbon (45°)/E‐glass (135°), Carbon (90°)/E‐glass (0°), Carbon/E‐glass (alternating layer), and Carbon/E‐glass (alternating layer 45°) were manufactured. Three‐point bending test and dynamic mechanical test were conducted to understand the flexural modulus and viscoelastic behavior (storage modulus, loss modulus, and loss tangent) of the composites. Dynamic mechanical test was performed with the dual cantilever method, at four different frequencies (1, 5, 10, and 20 Hz) and temperatures ranging from 30 to 150°C. The experimental results of storage modulus, loss modulus, and loss tangents were compared with the theoretical findings of neat epoxy and various hybrid composites. The glass transition temperature (Tg) increased with the increase in frequency. A linear fit of the natural log of frequency to the inverse of absolute temperature was plotted in the activation energy estimation. The interphase damping (tanδi) between plies and the strength indicator (Si) of the hybrid composites were estimated. It was observed that the neat epoxy had more insufficient storage and loss modulus and a high loss tangent at all the frequencies whereas hybrid composites had high storage and loss modulus and a low loss tangent for all the frequencies. Compared with other hybrid composites, Carbon (90°)/E‐glass (0°) had higher strength and activation energy. The result of reinforcement of hybrid fiber in neat epoxy significantly increases the material's strength and stability at higher temperatures whereas decreasing free molecular movement.

An experimental study on the effects of introducing carbon nanotube on low velocity impact behavior of carbon/aramid fiber reinforced intra-ply hybrid composites

In this research, the addition effects of Multi Wall Carbon Nanotube (MWCNT) on low velocity impact behavior of Carbon/Aramid Fiber Reinforced (CAFRP) intra-ply hybrid composites were studied. In this regard, three types of pure, 0.1 wt.% and 0.5 wt.% introduced CAFRP intra-ply hybrid composites were fabricated by Vacuum Assisted Resin Infusion Molding (VARIM) method. The profile energy method was used to determine the penetration and perforation threshold. The main purpose of this research was to improve the impact behavior of CAFRP by addition of MWCNT to the matrix of these composites. The low velocity impact test was also carried out in 30, 50, 80 and 120 J energy values. The effect of addition MWCNTs in the matrix of composite was investigated by plotting force, absorbed energy and deflection vs. time and the key parameters of impact test such as maximum contact force, absorbed energy, deflection and duration time were compared for pure and multi scale CAFRP composited. According to the results, the addition of MWCNT improved the low velocity impact behavior of CAFRP intra-ply hybrid composites by not only increasing the toughness of epoxy matrix but also upgrade the adhesion of carbon fibers to the epoxy matrix. It was also found that fiber breakage, fiber pull out, matrix cracking, delamination and fiber matrix debonding were the most important failure modes in these types of tested composites.

Evaluation of tensile properties on glass/carbon fiber epoxy pure, interply, and locally nested intraply hybrid composites

AbstractIn this study, the behavior of pure glass fiber/epoxy, pure carbon fiber/epoxy, interply hybrid, and locally nested intraply hybrid composites under tensile load was investigated. The specimens were produced by the vacuum‐assisted resin transfer molding (VARTM) method. Interply hybrid composites showed approximately the average tensile strength of the glass and carbon fiber/epoxy composites, with 603 MPa. Intraply hybrid composites had 17% lower tensile strength than pure glass fiber/epoxy composites due to the discontinuity of the fibers in the structure. Therefore, pure or interply hybrid composites are suitable in cases where tensile strength is more important, while in special cases where different properties are desired in different regions of a monolithic structure, locally nested intraply hybrid composites can be used. While the finite element analysis (FEA) results of pure and interply hybrid composites were very close to the tensile test, the amount of deviation increased in intraply hybrid composites due to fiber discontinuity. Fiber and void volume fractions of hybrid specimens were found to be around 62% and 1.45%, respectively. The numerical and experimental results of pure carbon fiber/epoxy composite are validated by the analytical solution.

Self-Sensing Hybrid Fibre-Reinforced Polymer for Structural Health Monitoring (SHM)

Hybrid composite material has been widely used in many engineering applications (e.g., for automobiles)and has several advantages over conventional fibre-reinforced composite materials, such as high strength-to-weight ratio and low cost. However, combining two kinds of reinforcement fibre within a common matrix may lead to different failure modes, such as delamination between the layers and fragmentation when the structure is subjected to high loads. To avoid this problem, real-time damage detection should be integrated into the hybrid composite structures for structural integrity. This paper outlines the working mechanisms and the initial fabrication of an integrated capacitive sensor into the intra-ply hybrid composite. The tensile test was conducted to perform the basic characterization of the proposed sensor and provide self-sensing functionality (smart structure). The results illustrate that damage between layers can be detected by in-situ monitoring. It is shown that the initial damage was detected at the turning point where the relative change in capacitance begins to decrease and when the axial tensile force increases. In addition, the developed smart material has shown a linear sensitivity toward crosshead displacement up to the turning point, and applying the monitoring is useful in self-sensing for hybrid composites.

Comparative dynamic analysis of carbon, aramid and glass fiber reinforced interply and intraply hybrid composites

This study presents a comparative dynamic analysis of hybrid composites, which are suitable for new technological vehicles and possess greater advantages over non-hybrid fiber-reinforced composites. In this context, non-hybrid (NH), interply hybrid (IN) and intraply hybrid (IR) composites are manufactured. In the manufacturing process, NH and IN composites are utilized by using Carbon (C), Aramid (A), and Glass (G) while IR composites are manufactured with Aramid-Carbon (AC), Carbon-Glass (CG), Glass-Aramid (GA). In the manufacturing stage, a variety of layer numbers and fiber orientation angles is taken into consideration to determine the most advantageous structures for vibration characteristics. As there are a great number of productions required because of the parameters of interest, Taguchi production design is used. These composites are manufactured using Vacuum Assisted Resin Transfer Molding (VARTM). In accordance with the relevant standards, density, tensile, and dynamic properties are determined experimentally. Further, numerical models are developed using the ANSYS® software, and modal analysis is conducted. The results of the numerical analysis are compared with the experimental results. Taguchi analyses are performed to determine the most effective manufacturing configurations for the purpose. Consequently, IN and IR composites with similar content are compared to each other and the previous literature. According to the experimental and numerical results, the factors most effective in determining the natural frequency and damping ratio are layer numbers, orientation angles, and fabric types, respectively. The effectiveness of each parameter in the ranking is determined by using Taguchi levels.

Interlayer Defect Detection in Intra-Ply Hybrid Composite Material (GF/CF) Using a Capacitance-Based Sensor.

Combining two types of reinforcement fiber in a common matrix may lead to different failure modes such as micro-cracks between the layers when the structure is subjected to lower stress levels. Real-time damage detection should be integrated into the hybrid composite structure to provide structural integrity and mitigate this problem. This paper outlines the working mechanisms and the fabrication of an integrated capacitive sensor in an intra-ply hybrid composite (2 × 2 twill weave). Uniaxial tensile and flexural tests were conducted to characterize the proposed sensor and provide self-sensing functionality (smart structure). The sensitivity and repeatability of the capacitive sensor were measured to be around 1.3 and 185 µΔC/Co, respectively. The results illustrate that onset of damage between layers can be detected by in situ monitoring. It can be seen that the initial damage was detected at the turning point where the relative change in capacitance begins to reduce while the load increases. Finite element modeling was also constructed to analyze the test results and explain the reasons behind the turning point. It was shown that the carbon yarns experienced high transverse shear stress (τxz) in the crimp region, leading to inter-fiber cracks.

Strengthening of reinforced concrete beams without transverse reinforcement by using intraply hybrid composites

Concrete is currently among the most widely used materials all around the world. The main advantages of concrete include durability, versatility, and high compressive strength, but significant disadvantages include low tensile strength, low shear strength, and low ductility. To eliminate these disadvantages, longitudinal and transverse reinforcements are usually preferred. Steel is widely used as a reinforcement material in the world, but there is still research underway to find alternative materials. In recent decades, composite materials have been used to reinforce concrete instead of steel materials. This study focuses on Intraply Hybrid Composites (IHCs), which are had an important place in the composite industry and examines how these composites affect concrete beams as far as their shear strength is concerned. For this purpose, A length of 2 m RC beams, with no transverse reinforcement (RC2.0), is prepared and then reinforced with three IHCs, Aramid-Carbon (AC2.0), Glass-Aramid (GA2.0) and Carbon-Glass (CG2.0). After U-shape strengthening, the specimens are inspected in four-point bending tests and the effects of the IHCs are investigated on the shear strength of the beams. The experimental results show that there is an increase of 4.36%, 10.62%, and 15.28% in the ultimate load capacity of AC2.0, CG2.0, and GA2.0, respectively, compared to reference specimen, RC2.0. Furthermore, the type of hybrid composite has a direct impact on the failure modes of the RC beams. Consequently, the IHCs can provide a significant contribution to the structural behavior of RC beams.

Mechanical and Thermal Properties of Carbon/Basalt Intra-ply Hybrid Composites. I. Effect of Intra-ply Hybridization

The effects of intra-ply hybridization on mechanical and thermal properties of carbon/basalt fibers reinforced epoxy composites were experimentally investigated. Combination of superior mechanical properties of carbon fiber, good thermal stability and basalt fiber toughness is the main purpose of designing of these composites. Three types of homogeneous carbon fiber reinforced polymer (CFRP), basalt fiber reinforced polymer (BFRP) and intra-ply hybrid of carbon/basalt reinforced polymer (CBFRP) composites were fabricated by using vacuum assisted resin infusion molding (VARIM) method. All fabricated composite plates were cut according to ASTM standard. The effect of incorporation of basalt fiber with carbon fiber on mechanical properties, such as modulus of elasticity, tensile strength, flexural modulus, flexural strength and inter laminar shear strength (ILSS) were studied by bending, tensile and short beam shear (SBS) experiments. Measurement of thermal conductivity, dynamic mechanic analyze (DMA), thermogravimetric analyze (TGA) tests were also carried out for thermal characterization of fabricated homogeneous and hybrid composites. Furthermore, dynamic drop test (DDT) was used to evaluate hybridization effect on hydrophobicity of composites. The results indicated that the CBFP hybrid composites perform a moderate mechanical performance between homogeneous CFRP and BFRP composites. On the other hand, incorporation of basalt fiber in the structure of carbon fiber composite not only enhances the thermal stability of composites but also moderates the fabrication price by alternating cheaper basalt fiber with expensive carbon fiber.

High strain rate compression testing of intra-ply and inter-ply hybrid thermoplastic composites reinforced with Kevlar/basalt fibers

In this study, the influence of hybridization on the compression response of thermoplastic matrix-based composites under high strain rate loading was investigated. The intra-ply and inter-ply hybrid composites were manufactured with Kevlar/Basalt yarns as the reinforcements with Polypropylene as a matrix. Cylindrical composite specimens were laser cut from the flat compression moulded laminates. The composite specimens were loaded under high strain rate using split-Hopkinson pressure bar setup at strain rates ranging from 2815/s to 5481/s. The study revealed differences in the rate-dependent growth of peak stress, peak strain and toughness with the strain rate. Intra-ply hybrid composites with alternate weaving of Kevlar and basalt yarns exhibited highest peak stress as compared to the Inter-ply hybrid composites (alternate layers of Kevlar and basalt fabrics) and another intra-ply composite containing Kevlar in the warp and basalt in the weft direction. Whereas in inter-ply hybrid composite, with Kevlar as the loading face attained higher stress, while composite with Basalt as the loading face attained higher strain. SEM micrographs revealed that Kevlar on the loading face can bear the impact with lesser delamination as compared to the Basalt on the loading face. Damage studies revealed that Kevlar fiber surface loading results in higher stress as compared to basalt (brittle) surface loading with lower overall damage.

Hybrid Effect in In-Plane Loading of Carbon/Glass Fibre Based Inter- and Intraply Hybrid Composites

Experimental studies are presented on quasi-static tensile and compressive loading of composites hybridised at two levels: intraply and interply. Consistent reinforcements in the form of novel unidirectional fabrics were developed using T700SC carbon and E-CR glass fibres. Composites were manufactured using Resin Transfer Moulding process with epoxy resin and characterised to ensure consistency and comparability, further enabling easier understanding and confirmation of hybrid effect in a reliable way. Failure strain in tension for interply hybrid revealed a positive hybrid effect of +7.4%, while interply hybrid showed a negative hybrid effect of −6.4% in compression. Intraply hybrid with three carbon and three glass tows blocked together demonstrated the best mechanical performance among all hybrids; synergistic effects of +17.8% and +39.6% in tensile and compressive strength, respectively, was observed for this hybrid configuration. The results show that different hybridisation strategies can be exploited to balance cost and performance of composites for structural and lightweight applications.

Hybrid composites and intra-ply hybrid composites based on jute and glass fibers: A comparative study on moisture absorption and mechanical properties

Natural fibers are used as reinforcement in composites due to advantages such as high stiffness, lower density, lower cost, environmentally friendly nature and high availability. Nevertheless, these fibers have some drawbacks such as low moisture resistance and incompatibility with most polymers. This paper compares two different hybrid configurations: inter-layer (layer by layer) and intra-layer (yarn by yarn). The fibers used are jute (Corchorus capsularis) and glass, while the matrix selected is polyester. The composites are manufactured using the hand layup technique and the samples are characterized for moisture resistance and mechanical properties. The experimental bending modulus of both laminated configurations is compared with theoretical values as obtained by a combination of the mixing law and homogenization technique. The results show that the interlayer configuration of jute and glass fibers presents the least resistance to moisture compared to the other configurations studied. Finally, the theoretical mechanical predictions are found to be good (10% on average) despite the simplifications made in the calculations.

Investigation of Mode I Delamination Resistance in Inter-ply and Intra-ply Hybrid Composites Reinforced with Basalt/Nylon Woven Fabrics

Investigation of Mode I Delamination Resistance in Inter-ply and Intra-ply Hybrid Composites Reinforced with Basalt/Nylon Woven Fabrics

Theoretical assessment of the elastic modulus of natural fiber-based intra-ply hybrid composites

The applications of natural fibers composites are growing in many sectors such as automotive industry, furniture, packing and construction. This is mainly due to their advantages compared to synthetic fibers composites (i.e., low cost, low weight, abundant and renewable resources among others). Nowadays, all of the main international automotive manufactures use these materials and their use is expected to increase in this area. In this study, two analytical models: rule of hybrid mixtures modified (RoHM) and an analytical model based on classical lamination theory, were used to determine theoretically the elastic modulus of intra-ply natural fiber-reinforced hybrid composites. The predicted elastic modulus was compared further with the experimental elastic modulus of jute/ramie, jute/sisal and jute/curaua intra-ply hybrid composites. The prediction by the model based on classical lamination theory showed a good agreement with the experimental elastic modulus values with a maximum deviation of 10%, while the RoHM overpredicted the elastic modulus values with a maximum deviation of 44%. Other mechanical properties such as shear modulus and flexural modulus can also be predicted by the same model. The new approach presented can be adopted as a primary tool to predict the mechanical properties of intra-ply hybrid composites. However, there is still a possibility to refine the theoretical prediction of elastic modulus by accounting the curvature parameter due to interlacing of yarns in woven fabrics.

Effect of fiber loading directions on the low cycle fatigue of intraply carbon-Kevlar reinforced epoxy hybrid composites

Effect of fiber orientation on tensile and low cycle fatigue of intraply hybrid composites was investigated. In this work, intraply carbon/Kevlar fabric/epoxy hybrid composites were tested for static and cyclic loadings at 0°, 45° and 90° corresponding to carbon, off-axis and Kevlar fiber directions. Ambient fatigue tests were performed at stress levels established from static tests. Tensile results showed the best strength and modulus was in the carbon direction followed by Kevlar direction. At 45°, high ductility was observed associated to fiber rotation. Fatigue linear regression lines indicated a slower degradation rate in the Kevlar loading direction compared to the carbon loading direction. Large fatigue scatter in the Kevlar direction suggested two distinct phases of fatigue attributed to the stiffening of Kevlar fibers that further led to lower fatigue degradation. Investigation on residual strength of run-out samples and fracture modes were also presented with interesting findings.