Variation Of Fiber Volume Fraction Research Articles

Investigation of ballistic performance on metal-coir fiber composite laminate with variation of fiber volume fraction: Experimental and simulation

Investigation of ballistic performance on metal-coir fiber composite laminate with variation of fiber volume fraction: Experimental and simulation

Study on dynamic mechanical properties and microstructure of basalt fiber reinforced coral sand cement composite *

This study investigates the impact of basalt fiber on the static and dynamic compression of coral-sand cement-based composites, as well as the mechanisms for strengthening and toughening. The samples of basalt fiber-reinforced coral sand cementitious composite (BFRCSCC) with varying fiber volume fractions (0%, 0.2%, 0.4%, 0.6%, 0.8%) underwent quasi-static mechanical tests and impact dynamic tests using an MTS universal testing machine and a split Hopkinson pressure bar (SHPB). This study investigates the mechanical properties of BFRCSCC, focusing on static and dynamic compressive strength, dynamic stress-strain curve, strain rate effect, failure strain, toughness analysis, and energy dissipation mechanism. In terms of microstructure, specimens of BFRCSCC were tested using scanning electron microscopy (SEM). The results indicate that basalt fiber can significantly enhance the quasi-static compressive strength (fc)and dynamic compressive strength (fd)of coral sand cement-based composite materials. When the basalt fiber content is 0.4%, the static and dynamic compressive strength of BFRCSCC increases by 28.78% and 37.25% respectively compared to ordinary concrete. The analysis from a micro perspective indicates that the incorporation of basalt fiber in the concrete matrix enhances the hydration reaction between cement and the BFRCSCC interface. The spatial structure formed by basalt fiber contributes to the excellent toughening effect on the mechanical properties of BFRCSCC. As the content of basalt fiber increases (≤0.4%), the bridging effect becomes stronger. The dynamic increase factor (DIF) and toughness index of BFRCSCC exhibit a significant positive correlation with the strain rate effect. Basalt fibers can help drive the hydration products to fill the cracks or voids in the cement matrix, thereby increasing the material's density and enhancing the impact resistance of coral concrete. This can be utilized in practical engineering projects with high dynamic load demands.

Forecasting and characterization of composite pipeline based on experimental modal analysis and YUKI-gradient boosting

The surging demand for fiberglass pipe materials in the Oil and Gas transportation sectors are driven by their exceptional durability and ease of use. This study combined improved experimental and numerical analyses to assess the behavior of composite pipe and focused on characterizing it, especially in terms of identifying the frequency based on different crack lengths. Various tests, such as impact hammer tests and modal analysis, determine the pipe properties and natural frequencies. The study also investigates the impact of varying fiber volume fractions to refine material properties. To understand crack effects behavior, different crack lengths have been introduced into the pipes and analyzing the modal analysis using frequency and mode shapes. The effect of cracks into frequency based on experimental and developed numerical models is investigated. A predective model is developed based on YUKI-Gradient Boosting algorithms and Deep Artificial Neural Networks. To test the robustness of developed algorithm several tests are provided and the results show the effectiveness of YUKI-Gradient Boosting outperforms YUKI-Deep-ANN in accuracy and consistency.

Effect of PVA Fiber on the Mechanical Properties of Seawater Coral Sand Engineered Cementitious Composites.

The physical and mechanical characteristics of seawater coral sand engineered cementitious composites (SCECC) were examined through uniaxial compression, three-point bending, and splitting tensile tests. The mechanical properties were scrutinized under varying fiber volume fraction conditions (V = 0%, 0.575%, 1.150%, 1.725%, and 2.300%). The experimental results indicated that the compressive strength, three-point bending strength, and split tensile strength of SCECC tended to increase with the rise in fiber volume fraction. The strengths attained their maximum values of 45.88, 12.56, and 3.03 MPa when the fiber volume fraction reached 2.300%. In the compression test, the compressive strength of the 7-day specimen can achieve more than 78.50% of that observed in the 28-day specimen. Three-point bending test has revealed that SCECC exhibits favorable strain-hardening and multi-crack cracking characteristics. Fracture patterns of SCECC exhibited variations corresponding to changes in fiber content, as illustrated by their load-deformation curves, the addition of PVA fibers can change the damage mode of cementitious composites from brittle to ductile. The fracture energy of SCECC further attests to its elevated toughness. This is due to the fact that the fibers delay the formation of microcracks and prevent crack expansion, thus significantly increasing the deformability of the material. By verifying its strength, deformability, fracture energy, and other key performance indicators, the feasibility of SCECC in coastal construction projects has been clarified. The successful development of SCECC provides an innovative and high-performance option for the construction of future island projects.

Investigation of shear response due to variation of fiber volume fraction, transverse steel, and placement method on short span R/UHPC beams

This study investigates the response of small-scale, reinforced ultra high performance concrete beams. Seven specimens were cast and experimentally tested. Steel fiber volume fraction, amount of longitudinal and transverse steel reinforcement, and casting direction varied between specimens. High longitudinal reinforcement ratios of 4.1% and 9.5% were expected to drive relatively large shear demands and low steel fiber volume fractions of 0.5% and 1% were expected to decrease the UHPC’s ability to resist tension, shear, and compression. Specimens were either cast at one end or mid-span. All specimens failed in shear, as expected. R/UHPC beams with only 0.5% fibers and a stirrup spacing equal to half the beam’s depth carried more ultimate load than beams with 1% fibers and twice the stirrup spacing. At a 0.5% fiber volume fraction, UHPC performed well, exhibiting fiber bridging in tension and resisting spalling in compression. As longitudinal reinforcement ratio increased from 4.1% to 9.5%, load carrying capacity generally increased, but not proportional to the increase in steel. Placement method did not influence fiber orientation in the R/UHPC beams when measured in 2D planes transverse or longitudinal to the specimens’ major axis. The longitudinal and transverse reinforcement interrupted fiber flow and prevented significant fiber alignment; combined with the short span of the beams, these factors mitigated the influence of placement method.

Investigating the Effect of Varied Short Bamboo Fiber Content on the Thermal, Impact, and Flexural Properties of Green Epoxy Composites

ABSTRACT In this study, the thermal and mechanical characteristics of bamboo fiber-reinforced greenpoxy matrix composites were evaluated by varying the fiber loading from 30wt.% to 60wt.% during the compression molding process. The thermal behavior using dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA) and their impact and flexural properties of the composites were studied. The results indicate that thermal characterization, the highest peak E’ was observed: B-40 > B-60 > B-30 > B-50, while the peak E’‘ was found to be B-40 > B-30 > B-60 > B-50. The order for tan delta was B-30 > B-40 > B-50 > B-60. The TGA results indicated improved thermal stability with increasing fiber loading, as evidenced by higher residue % and lower weight loss %. Regarding the mechanical properties the impact strength of the composites increased with increasing fiber loading, with the maximum value of 8435.33 J/m2 at 50wt.%. The composite with a 60wt.% fiber loading showed the highest flexural modulus (4.70GPa), while the flexural strength improved at 40wt.%. The SEM analysis of fractured specimens from flexural tests of composite materials with varying fiber volume fractions revealed that an optimal balance between fiber and matrix resin enhanced mechanical properties.

Rapid evaluation and prediction of cure-induced residual stress of composites based on cGAN deep learning model

In this piece of present work, we propose a deep learning model driven by conditional generative adversarial network (cGAN) for rapid evaluation and prediction of cure-induced residual stress (CRS) of composites. The CRS is evaluated by solving for the material behaviors of the cure kinetics, viscoelasticity, thermal expansion, and cure shrinkage under heat transfer condition using finite element (FE) method. The geometry and CRS fields are extracted from numerous simulations and subsequently utilized in the proposed cGAN training process. With this end-to-end unsupervised learning, the cGAN model can predict the CRS with high fidelity based on the fiber random distributed microstructure and capture the variation of fiber volume fraction. In qualitative measures, peak signal to noise ratio (PSNR) and structure similarity index (SSIM) are employed for accuracy verification. Moreover, the cGAN model can also significantly reduce the computational cost and provide some insights for optimizing the manufacturing process of composites.

Flexural behavior of high-strength steel bar reinforced UHPC beams with considering restrained shrinkage

Despite the excellent mechanical properties of ultra-high performance concrete (UHPC), UHPC beams with a conventional reinforcement ratio consistently demonstrate limited ductility. Therefore, this study aims to enhance the ductility of reinforced UHPC beams by regulating the tensile interaction between steel fibers and reinforcement. Six UHPC beams with varying fiber volume fractions and reinforcement ratios were tested under flexure. The effect of restrained shrinkage on flexural behavior was emphatically investigated. A cracked section analysis was also implemented to predict cracking behaviors of UHPC beams and was verified by experimental results. The test results revealed an increase in the ductility of UHPC beams with an increasing reinforcement ratio, while a decrease was observed with an increasing fiber volume fraction. The contribution of UHPC tensile capacity decreased significantly with the increase in the reinforcement ratio because of the restrained shrinkage. The stiffness and crack control capacity of reinforced UHPC beams reaches a plateau when the sum of reinforcement ratio and fiber volume fraction exceeds 3.1%. Increasing the fiber content is more effective than increasing the reinforcement ratio in limiting crack development, whereas the converse is true for improving the flexural capacity.

Dielectric properties of unidirectional and biaxial flax/epoxy composites at frequencies up to 1 GHz

The relative permittivity of flax/epoxy composites in unidirectional and biaxial orientations was mapped in the frequency range of 1 kHz to 200 kHz, and for the first time in the range of 1 MHz to 1 GHz. In addition, permittivity was investigated for the first time in the temperature range between − 20 °C and 50 °C. These composites, produced using the vacuum infusion process, are increasingly used for sustainable and lightweight structural components in the automotive industry. The relative permittivity was determined using a self-developed plate capacitor with an LCR bridge and an impedance analyzer. An examination of the microstructure of the flax/epoxy composites shows that the fibers are disordered in the composite, resulting in local variations in fiber volume fraction. Furthermore, it was shown that the matrix also infiltrates into the fiber itself, resulting in an increase of the matrix fraction. It was found that unidirectional fabrics had a higher relative permittivity than biaxial fabrics, due to a higher fiber volume fraction and lower proportion of epoxy. The results suggest that it is the fiber volume fraction, rather than the manufacturing process and fiber orientation, that primarily determines the relative permittivity. It was also found that the permittivity continues to decrease below room temperature and thus behaves in a manner typical of the material in this temperature range as well.

Micromechanics-Based Modeling of SiC/SiC Ceramic Matrix Composites and Structures

The behavior and response of ceramic matrix composites (CMCs), in particular silicon carbide fiber reinforced silicon carbide matrix (SiC/SiC), is affected by many factors such as variation of fiber volume fraction, residual stresses resulting from processing of the composites at high temperature, random microstructures, and the presence of matrix flaws (e.g., voids, pores, cracks etc.) as well as general material nonlinearity and heterogeneity that occurs randomly in a composite. Residual stresses arising from the phase change of constituents are evaluated in this paper and it is shown that they do influence composite strength and need to be properly accounted for. Additionally, the microstructures (location of fiber centers, coating thickness etc.) of advanced CMCs are usually disordered (or random) and fiber diameter and strength typically have a distribution. They rarely resemble the ordered fiber packing (square, rectangular, or hexagonal) that is generally assumed in micromechanics-based models with periodic boundary conditions for computational expediency. These issues raise the question of how should one model such systems effectively? Can an ordered hexagonal packed repeating unit cell (RUC) accurately represent the random microstructure behavior? How many fibers need to be included to enable accurate representation? Clearly, the number of fibers within an RUC must be limited to insure a balance between accuracy and efficiency. NASA’s in-house micromechanics-based code MAC/GMC provides a framework to analyze such RUCs for the overall composite behavior and the FEAMAC computer code provides linkage of MAC/GMC to the commercial FEA code, ABAQUS. The appropriate level of discretization of the RUC as well as the analysis method employed, i.e., Generalized Method of Cells (GMC) or High Fidelity Generalized Method of Cells (HFGMC), is investigated in this paper in the context of a unidirectional as well as a cross-ply laminated CMC. Results including effective composite properties, proportional limit stress (an important design parameter) and fatigue are shown utilizing both GMC as well as HFGMC. Finally, a few multiscale analyses are performed on smooth bar test coupons as well as test coupons with features such as open-hole and double notches using FEAMAC. Best practices and guidance are provided to take these phenomena into account and keep a proper balance between fidelity (accuracy) and efficiency. Following these guidelines can account for important physics of the problem and provide significant advantages when performing large multiscale composite structural analyses. Finally, to demonstrate the multiscale analysis framework, a CMC gas turbine engine vane structure is analyzed involving a progressive damage model.

Influence of fibre on mechanical behavior of Ramie fibre /polystyrene hybrid composite

Natural fibre composites are now commonly regarded as a reinforcing component in polymer matrix composites. For their biodegradability, less density, and higher specific characteristics, polymer matrix-reinforced natural fibre composite materials are commonly employed in industry. The tensile characteristics of Ramie fibre woven fabrics and Polystyrene (PS) composite laminates were investigated and impact tests, to examine how the volume percentage of the fibre influenced them. In the beginning, the thermal-compression method was used to create composite laminates with varying fibre volume fractions by layering different fabrics. The mechanical characteristics of material are determined by conducting tensile, shear and biaxial tensile testing. Additionally, an effect hammer testing was done to determine the frequencies as well as restraining properties of stratified composite structures. The viscoelastic behavior of Ramie fabrics/PS composite laminates changes to elastic as the volume percentage of the fibres increases. Tensile strength is enhanced by increasing fibre content. On the other hand, the increased fibre volume has an effect on the natural frequency and damping ratio.

Analisis Kekuatan Bending Komposit Lamina Serat Ijuk Anyam dan Serat Ijuk Acak bermatriks Polyester

The current automotive industry uses composite materials as an alternative material to replace metal or plastic, due to the advantages of composite materials that have biodegradable properties and support environmental sustainability. Composite materials can be used as car body protectors, as a protector composite materials must withstand compressive loads. Referring to this, the research will be carried out through flexural testing. Study aim is to analyze variations of fiber volume fraction effect to the flexural strength. Method of making composite materials using hand layup then press mold, variations in fiber volume fraction 25%, 30%, 35%, 40%, and 45%. Flexural testing is carried out according to ASTM D-790. The morphology analysis was also carried out on the fractures of result of flexural test. Flexural testing results show that the highest flexural strength is founded in the fiber volume fraction 50% and the lowest flexural strength is founded in the fiber volume fraction 25%, 724.4 MPa and 435.8 MPa, respectively. A suitable composition in the fiber volume fraction of 40% can produce an optimal bond between the matrix and the fiber. Observing the morphology of the fracture and the cross-section of the fracture flexural testing results, it was found that there were fiber fractures with the characteristics of fiber pullout and delamination in each test specimen.

Micromechanics Based Finite Element Analysis of Effective Elastic Properties of Natural Fiber Reinforced Composites

ABSTRACT For seamless use of natural fiber-reinforced composites (NFRCs) in the industry, it is essential to evaluate the elastic characteristics of NFRCs. In the present work, a finite element (FE) analysis has been done in ABAQUS for finding the effective elastic properties of the NFRCs. A comparative study of the effectiveness of different micromechanical models for assessing the effective properties of NFRCs has been discussed. The findings of the FE analysis have been compared to the effective properties obtained from the micromechanical models. It is observed that the elastic properties obtained through FE analysis are found to be in accordance with the elastic properties computed using different micromechanical models. Further, an error analysis method (Root mean squared scaled error) has been employed to quantify the results obtained from other micromechanical models and choose the most suitable model for each elastic property. There is no unified model for all the elastic properties over the varying fiber volume fraction; it is specific for a particular elastic property and fiber volume fraction.

Effects of Kenaf Fibre on Fresh Properties of Fibrous Concrete

As a result of global quest for sustainable materials to achieve a bio based economy and low carbon foot print environment, the use of fibre to produce fibrous concrete composite has continuously received significant research attention. While several researches have been conducted on metallic and synthetic fibrous concretes, they exhibit several unavoidable drawbacks and bio fibrous concrete has proven to be a better alternative. Therefore, the effect of fibre volume fraction and fibre length on fresh properties of concrete was investigated. The bio fibrous concrete mix was made of six different fibre volume fractions (0.25%, 0.5%, 0.75%, 1%, 1.5% and 2%) and corresponding three different fibre lengths of 25 mm, 50 mm and 75 mm. A concrete mix proportion of grade 30 N/mm2 at 28 days target strength was prepared. A total of 19 different concrete mixes comprising of one PC mix was the control for the experiment, and 18 different mixes of Kenaf bio fibrous concrete composite (KBFCC) at varying fibre volume fraction (vf) and fibre length (lf) were tested. These mixes were tested for workability (slump, compacting factor and Vebe test) and fresh density. The slump and Vebe time for KBFCCs were 5–100 mm and 3–79 seconds respectively. The slump and Vebe time for PC were 120 mm and 3 seconds respectively. A significant drop from 0.951 to 0.809 for fibre length of 25 mm, 0.947 to 0.799 for fibre length of 50 mm and 0.931 to 0.793 for fibre length of 75 mm was observed for the compacting factor value. Though, KBFCC with fibre content below 1% was workable in spite of its low slump, its high Vebe time and low compacting factor. For fibre volume of 1% and above, the workability of concrete decreased and became very stiff with balling effect. It was seen that fresh density of PC concrete (2358 kg/m3) was higher compared to those of KBFCC (2105-2339 kg/m3), however, both values were lower than 2400 kg/m3 threshold specified by the BS code of practice. The study therefore recommended that fibre contents lesser than 1% and 50 mm length can be used in order to have good fresh properties performance.

Nonlinear Inverse Analysis for Predicting the Tensile Properties of Strain-Softening and Strain-Hardening UHPFRC.

The tensile stress–strain response is considered to be the most important and fundamental mechanical property of ultra-high-performance fiber-reinforced concrete (UHPFRC). Nevertheless, it is still a challenging matter for researchers to determine the tensile properties of UHPFRC. As a simpler alternative to the direct tensile test, bending tests are widely performed to characterize the tensile behavior of UHPFRC, but require further consideration and a sophisticated inverse analysis procedure. In order to efficiently predict the tensile properties of UHPFRC, a nonlinear inverse method based on notched three-point bending tests (3PBT) was proposed in this paper. A total of fifteen UHPFRC beams were fabricated and tested to evaluate the sensitivity of the predicted tensile behavior to variations in fiber volume fraction. A segmented stress–strain model was used, which is capable of describing the various tensile properties of UHPFRC, including strain softening and strain hardening. A more approximate formulation was adopted to simulate the load–deflection response of UHPFRC beam specimens. The closed-form analytical solutions were validated by tensile test results and existing methods in literature. Finally, parametric studies were also conducted to investigate the robustness of the proposed method. The load–deflection responses obtained from notched 3PBT could be easily converted into tensile properties with this inverse method.

PENGARUH VARIASI FRAKSI VOLUM SERAT TANDAN KOSONG KELAPA SAWIT DAN SERAT AMPAS TEBU TERHADAP KEKUATAN TARIK KOMPOSIT HYBRID BERMATRIK POLYESTER

Composite is a combination of two or more different materials that are combined with the aim of getting better strength from the constituent materials. This study aims to identify the effect of variations in fiber volume fraction and determine the proportion of the best volume fraction based on the tensile and flexural strength values in hybrid composites reinforced with EFB fiber and bagasse fiber. The composite manufacturing process was carried out using the compression molding method with variations in fiber volume fraction 6:14, 8:12, 10:10, 12:8 and 14:6. The tests carried out were density testing (ASTM C271) and tensile strength (ASTM D3039 ). The highest tensile strength test results were obtained at fiber volume fraction 8:12 with a value of 17.39 Mpa.

Effect of fiber volume fraction on tensile strength and fracture analysis of corn husk reinforced epoxy resin composite

This study aims to determine the effect of volume fraction of corn husk fiber as reinforcement in epoxy matrix composites on tensile strength and fracture analysis of specimens. This study used a variation of fiber volume fraction of 20%, 30%, 40%, 50% by using the Vacuum Assisted Resin Infusion (VARI) method. Tensile testing and analysis of fracture patterns were carried out to determine the mechanical properties of the material. The results showed that the addition of corn husk fiber volume fraction to the corn husk reinforced epoxy resin composite could increase the tensile strength value. Tensile strength values for fiber length of 165 mm with variations in fiber volume fraction 20%, 30%, 40%, and 50% get the tensile stress values of 26.16 N/mm2, 27.09 N/mm2, 27.82 N/mm2, and 30.61 N/mm2. The mechanism of fiber pull out, debonding, and the rich matrix also occurs in the microstructure analysis of the tensile test fracture results.

Fiber packing and morphology driven moisture diffusion mechanics in reinforced composites

Fiber reinforced polymer composite (FRPC) materials are extensively used in lightweight applications due to their high specific strength and other favorable properties including enhanced endurance and corrosion resistance. However, these materials are inevitably exposed to moisture, which is known to drastically reduce their mechanical properties caused by moisture absorption and often accompanied with plasticization, weight gain, hygrothermal swelling, and de-bonding between fiber and matrix. Hence, it is vital to understand moisture diffusion mechanics into FRPCs. The presence of fibers, especially impermeable like Carbon fibers, introduce tortuous moisture diffusion pathways through polymer matrix. In this paper, we elucidate the impact of fiber packing and morphology on moisture diffusion in FRPC materials. Computational models are developed within a finite element framework to evaluate moisture kinetics in impermeable FRPCs. We introduce a tortuosity factor for measuring the extent of deviation in moisture diffusion pathways due to impermeable fiber reinforcements. Two-dimensional micromechanical models are analyzed with varying fiber volume fractions, spatial distributions and morphology to elucidate the influence of internal micromechanical fiber architectures on tortuous diffusion pathways and corresponding diffusivities. Finally, a relationship between tortuosity and diffusivity is established such that diffusivity can be calculated using tortuosity for a given micro-architecture. Tortuosity can be easily calculated for a given architecture by solving steady state diffusion governing equations, whereas time-dependent transient diffusion equations need to be solved for calculating moisture diffusivity. Hence, tortuosity, instead of diffusivity, can be used in future composites designs, multi-scale analyses, and optimization for enabling robust structures in moisture environments.

Characterization of continuous carbon fibre reinforced 3D printed polymer composites with varying fibre volume fractions

Fused deposition modelling (FDM) is one of the most popular additive manufacturing (AM) technique which is used to investigate the elastic properties of 3D printed polyamide-based polymer composites structures. The aim of this work is to study the mechanical properties of continuous carbon fibre reinforced polyamide polymer composite samples using tensile and flexural testing by varying the fibre volume contents with applying pressure, temperature and holding the samples for 60 minutes in the platen press. The results showed that the strength and stiffness increased with the increase in fibre volume content (fraction). Hot pressed samples exhibited the increase in tensile strength by about 27 % and elastic modulus by 11 % because of increasing the fibre volume fraction from 29 % to 35%. Synergetic effect of both short and continuous carbon fibre was also studied, and it was observed that the tensile properties were higher for the samples reinforced with short and continuous fibre than only continuous fibre polymer composites. Effects of voids on 3D printed continuous carbon fibre-reinforced polymer composites were quantified. A microstructure study of the 3D printed polymer composites was carried out using scanning electron microscope (SEM). Following SEM analysis on the tested specimens, it was observed that there was a strong correlation between the mechanical properties and the microstructure. Fibre volume fraction was measured using acid digestion method to determine the amount of fibre contents before and after hot pressing (compaction). From Micro- Computed Tomography (µCT) it was confirmed that hot pressing reduced the void content which in return increased the strength and modulus.

Hyperstatic steel structure strengthened with prestressedcarbon/glass hybrid laminated plate

This paper presents a careful theoretical investigation into interfacial shear stresses in steel beam strengthened with prestressed carbon/glass hybrid laminated plate. A closed-form rigorous solution for interfacial shear stress in steel beams strengthened with bonded prestressed carbon/glass hybrid laminated plates and subjected to a uniformly distributed load, is developed using linear elastic theory and including the variation in fiber volume fraction of carbon/glass hybrid laminated. The results show that there exists a high concentration of shear stress at the ends of the laminate, which might result in premature failure of the strengthening scheme at these locations. A parametric study has been conducted to investigate the sensitivity of interface behavior to parameters such as laminate and adhesive stiffness, the proportions and volume fraction of the fiber of carbon/glass hybrid laminated, the thickness of the laminate and the effect of prestressing where all were found to have a marked effect on the magnitude of maximum shear and normal stress in the composite member. This solution is intended for application to beams made of all kinds of materials bonded with a thin composite plate. This research is helpful for the understanding on mechanical behaviour of the interface and design of such structures.