Fiber Polymer Matrix Composites Research Articles

On Cyclic-Fatigue Crack Growth in Carbon-Fibre-Reinforced Epoxy-Polymer Composites.

The growth of cracks between plies, i.e., delamination, in continuous fibre polymer matrix composites under cyclic-fatigue loading in operational aircraft structures has always been a very important factor, which has the potential to significantly decrease the service life of such structures. Whilst current designs are based on a 'no growth' design philosophy, delamination growth can nevertheless arise in operational aircraft and compromise structural integrity. To this end, the present paper outlines experimental and data reduction procedures for continuous fibre polymer matrix composites, based on a linear elastic fracture mechanics approach, which are capable of (a) determining and computing the fatigue crack growth (FCG) rate, da/dN, curve; (b) providing two different methods for determining the mandated worst-case FCG rate curve; and (c) calculating the fatigue threshold limit, below which no significant FCG occurs. Two data reduction procedures are proposed, which are based upon the Hartman-Schijve approach and a novel simple-scaling approach. These two different methodologies provide similar worst-case curves, and both provide an upper bound for all the experimental data. The calculated FCG threshold values as determined from both methodologies are also in very good agreement.

Extraction and characterization of a novel cellulosic fiber derived from the bark of Rosa hybrida plant

The current investigation aims to choose an alternate potential replacement for the nonbiodegradable synthetic fibers used in polymer composites. This goal motivated the thorough characterization of Rosa hybrida bark (RHB) fibers. The research explored fiber characterization such as morphological, mechanical, thermal, and physical properties. The suggested fiber features a percentage of cellulose, hemicellulose molecules, and lignin of 52.99 wt%, 18.49 wt%, and 17.34 wt%, respectively according to chemical composition studies, which improves its mechanical properties. It is suitable for lightweight applications due to its decreased density (1.194 gcm−3). The purpose of the Fourier transform infrared spectroscope was to observe and record how various chemical groups were distributed throughout the surface of the fiber. The presence of 1.41 nm-sized crystalline cellulose and further XRD analysis showed a crystallinity index of 75.48 %. Scanning electron microscope studies revealed that RHB fibers have a rough surface. According to a single fiber tensile test, for gauge length (GL) 40 mm, Young's modulus and tensile strength of RHB fibers were 6.57 GPa and 352.01 MPa, respectively, and for GL 50 mm, 9.02 GPa and 311 MPa, respectively. Furthermore, thermo-gravimetric examination revealed that the isolated fibers were thermally stable up to 290 °C and the kinetic activation energy was found to be 75.32 kJ/mol. The fibers taken from the Rosa hybrida flower plants' bark exhibit qualities similar to those of currently used natural fibers, making them a highly promising replacement for synthetic fibers in polymer matrix composites.

Study of mechanical properties of the natural-synthetic fiber reinforced polymer matrix composite

In the era of competition and modernization of existing materials in advancement to their properties and their mechanical behaviour. The primary concern when it comes to improving the mechanical behaviour for the natural reinforced fiber polymer composites is that synthetic reinforced fiber polymer matrix composites will eventually replace them in numerous engineering applications. This study addresses the tensile strength of carbon fibre, jute fibre, and carbon fibre composite hybridization. The combination of natural and the synthetic fibres is essential for enhancing mechanical characteristics of a composite material. Carbon and glass, for example, are stiffer and stronger than natural fibres. The primary aim of this research is to improve composite material tensile strength by incorporating synthetic fibre into natural fibre. The point of the study is to evaluate the tensile behaviour of a composite material specimen. Using the ABAQUS software package, a carbon/jute fibre reinforced hybrid polymer composite was numerically constructed to assess the tensile behaviour of the composite samples. Experimental investigation of the composite laminate of the different materials is implemented using Hashin’s Criteria and Von mises stress for tensile simulation and It has been noticed that surface treatment of fibre can improve bonding between fibre and matrix. Natural fibre polymer composites with improved mechanical attributes are replacing synthetic fibre reinforced polymer matrix composites (PMCs) in wide range of commercial applications. According to the results, jute fibres have a lower tensile strength than the hybrid fiber-reinforced composite material. Addition of carbon fibre gradually increases the composite laminate's strength. We can obtain the tensile parameters of the materials and constituents by applying modelling to the experimental results.

A review to elucidate the multi-faceted science of the electrical-resistance-based strain/temperature/damage self-sensing in continuous carbon fiber polymer-matrix structural composites

A review to elucidate the multi-faceted science of the electrical-resistance-based strain/temperature/damage self-sensing in continuous carbon fiber polymer-matrix structural composites

Reinforced Structure Effect on Thermo-Oxidative Stability of Polymer-Matrix Composites: 2-D Plain Woven Composites and 2.5-D Angle-Interlock Woven Composites.

The thermo-oxidative stability of carbon fiber polymer matrix composites with different integral reinforced structures was investigated experimentally and numerically. Specimens of 2-D plain woven composites and 2.5-D angle-interlock woven composites were isothermally aged at 180 °C in hot air for various durations up to 32 days. The thermal oxidative ageing led to the degradation of the matrix and the fiber/matrix interface. The degradation mechanisms of the matrix were examined by ATR-FTIR and thermal analysis. The interface cracks caused by thermal oxidative ageing were sensitive to the reinforced structure. The thermo-oxidative stability of the two composites was numerically compared in terms of matrix shrinking and crack evolution and then experimentally validated by interlaminar shear tests.

Characterization of cure residual strain development and associated structural distortion in carbon fiber polymer matrix composites

A comprehensive experimental methodology has been developed to measure the in situ cure residual strain (CRS) generation in carbon fiber reinforced polymer (CFRP) laminates using embedded fiber Bragg grating (FBG) sensors. In order to delineate the effect of anisotropy, heterogeneity, laminate thickness and geometry, in situ CRS is measured in pristine epoxy, uni-directional (UD)-CFRPs, multi-directional (MD)-CFRPs and L-shaped MD-CFRP laminates. In this study, emphasis is laid on quantifying the variation in CRS magnitudes as a function of laminates lay-up sequence and thickness. Calibration of FBG sensors are carried out by following well established procedures. Structural distortion due to CRS is correlated using embedded FBG sensor and measured using the coordinate measurement machine (CMM). The presented results show a uniform CRS development across the thickness in MD-CFRP laminates as compared to L-shaped MD-CFRP laminates.

Determination of residual stresses in a single FBG fiber/epoxy composite system

A new approach to determine residual fiber and matrix stresses in single fiber Bragg grating (FBG) fiber polymer matrix composites is developed based on the earlier work by Hoffman et al., 2020 [( Hoffman et al., 2020) 1] and Khadka et al., 2020 [( Khadka et al., 2020) 2]. In this new study, our already measured fiber strains in the composites based on room temperature (RT) and higher temperature (HT) epoxies were used to determine the stresses in the fibers. The total manufacturing residual stresses in the fibers were also separated for the curing and cooling parts of the manufacturing cycles. The cooling stresses for both epoxy systems were then independently verified through single fiber thermal numerical models. Subsequently, using our new methodology based on the Eshelby misfit approach and the single fiber thermal models, the total residual stresses in the matrix were found and then separated into the curing and cooling stresses. The maximum axial stresses at the matrix/fiber interfaces were found to be increasing with an increase in the curing temperature of the RT epoxy. For the highest curing temperature of the RT resin (70 °C), the residual axial stresses in the matrix (20 MPa) were close to the stresses in the HT epoxy (25 MPa) at the curing temperature of 121 °C. The curing matrix stresses were observed to be significant for both epoxy systems with their contributions to the total stress ranging from 28% to 48% depending on the resin type and curing conditions.

Effect of Graphene Oxide-Boron Nitride-Based Dual Fillers on Mechanical Behavior of Epoxy/Glass Fiber Composites

Graphene and its derivatives have excellent properties such as high surface area, thermal, and mechanical strength, and this fact made the researchers promote them as the possible filler material for fiber-matrix composite. The current research deals with validation on the effect of graphene oxide boron nitride filler over mechanical and thermal stability of epoxy glass fiber polymer matrix composite. The objective of this experimental investigation is to develop glass fiber reinforced polymer composites with hybrid filler addition. The matrix material selected is epoxy resin, whereas the glass fiber is selected as reinforcement, while boron nitride and graphene oxide are chosen as fillers. Compression moulding methodology is followed to develop the composites with the constant percentage of fiber loading, graphene oxide filler, and varying boron nitride content from 0 to 3 wt.% at an equal interval of 1 wt.%. The developed composite is analyzed for mechanical properties, and the fractured surface is analyzed through the scanning electron microscope. The addition of hybrid fillers enhances the fiber-matrix bonding strength and improves the thermal and mechanical properties up to a specific limit. Thermal gravimetric analysis was conducted to understand the thermal behavior of composite. The results revealed that the addition of filler improved the thermal stability of the composites.

Mechanical Characterization of Areca Fiber and Coconut Shell Powder Reinforced Hybrid Composites

The use of natural fibers in polymer matrix composites are increases because of their advantages like good stiffness, strength, environmental friendly, low cost and biodegradable. In the present investigation, hybrid fiber reinforced composites are fabricated using areca fiber and coconut shell powder (CSP) as reinforcement in epoxy resin. Unidirectional areca fiber and CSP reinforced epoxy composites were fabricated by varying the overall fiber loading (10, 20, 30, and 40 wt.%) and different weight ratios of areca fiber and CSP (1:1, 1:3, and 3:1). Effect of fiber loading and weight ratio on mechanical properties like tensile strength, tensile modulus, flexural strength, flexural modulus, interlaminar shear strength (ILSS), impact energy and surface hardness of hybrid composites were evaluate experimentally. All the hybrid composite samples fabrication and mechanical testing was done as per ASTM standards. The experimental investigation reveals that the tensile, flexural and ILSS properties show their maximum values at 30 wt.% of fiber loading with areca fiber and CSP weight ratio as 1:1. From the impact and hardness results it has been found that composites with areca fiber and CSP weight ratio as 3:1 and 1:1 respectively shows their maximum values at 40 wt.% of fiber loading. Interfacial analysis of the hybrid composites were also observed by using scanning electron microscope (SEM).

Tribological Behavior of Syngonanthus nitens Natural Fiber Reinforced Epoxy Composite

Syngonanthus nitens (SN), locally called Sikki grass, a natural fiber whose potential as a reinforcement in polymer matrix composite for tribology applications has not been explored till date. The present work aims to investigate the study of solid particle impact on erosion wear behavior of this natural fiber polymer matrix composite. The study describes the preparation of a new set of composites by hand lay-up technique, using varying weight proportions (10, 20, 30 and 40 wt. %) of the SN fiber reinforced with epoxy resin. The erosion wear behavior of composites was carried out by air jet erosion test apparatus with four different impingement angles (30°, 45°, 60° and 90°) and at four different impact velocities (48, 70, 82 and 109 m/s). The experimented composite showed semi-ductile erosion wear behavior with maximum wear rate at 45° impingement angle for lower velocities and maximum wear rate at 60° at higher velocities. The morphology and damage mechanism of eroded surfaces were examined by SEM analysis and reported in this paper.

Hierarchical Multiscale Approach for Modeling the Deformation and Failure of Epoxy-Based Polymer Matrix Composites

Coarse-grained molecular dynamics (CG-MD) simulations were conducted to characterize the molecular structure and mechanical properties in the epoxy matrix around fibers in polymer matrix composites (PMCs). From these simulations, the molecular structure was quantified by measuring the free-volume hole radius distribution as a function of position from the matrix-fiber interface. Additionally, correlations between the epoxy mechanical properties and the average free-volume hole radius were established for different degrees of cross-linking. These results were then upscaled into a finite element model (FEM) of a PMC representative volume. The results from the CG-MD-informed FEM model were compared to conventional FEM simulations that assume uniform epoxy mechanical properties, and the results indicate that conventional FEM simulations overestimate the strength of PMCs and predict a symmetric damage evolution in the matrix. On the other hand, the CG-MD-informed FEM simulations predict a more realistic localization of damage around the fiber-matrix interface.

Investigation of Mechanical Properties and Characterization of Hybrid Natural Fibre Polymer Matrix Composites

Over the past decade, the perception of utilizing Natural fiber has come to be more main stream. Natural fibres are the best substitute with the growing environmental consciousness, which act as an alternative for synthetic fibers due to their promising properties. New cellulosic fibers were identified from banyan bark. This study targets at understanding the components of ficusbenghalensis extracted from the bark of the banyan tree and its mechanical properties. Here, we construct three types of plates. One set of plates is equipedd by random orientation process another set of plates by unidirectional orientation and the third plate by orientation of bi-directional tests. The mechanical properties are going to inhibit tensile and impact. The flexural test is directed at these plates. We can select high strength plate among them with the support of those tests’ results, and by comparing those plates.

Characterization of a new natural cellulosic fiber extracted from Derris scandens stem

The present study aims to identify a potential substitute for the harmful synthetic fibers in the field of polymer composites. With this objective, a comprehensive characterization of Derris scandens stem fibers (DSSFs) was carried out. The presence of high strength gelatinous fibers with a traditional hierarchical cell structure was found in the anatomical study. The chemical compositional analysis estimated the cellulose, hemicellulose, and lignin contents of 63.3 wt%, 11.6 wt%, and 15.3 wt%, respectively. Further analysis with XRD confirmed the presence of crystalline cellulose having a size of 11.92 nm with a crystallinity index of 58.15%. SEM and AFM studies show that these fibers are porous, and the average roughness is 105.95 nm. Single fiber tensile tests revealed that the DSSFs exhibited the mean Young's modulus and tensile strength of 13.54 GPa and 633.87 MPa respectively. Furthermore, the extracted fibers were found to be thermally stable up to 230 °C, as confirmed by thermogravimetric analysis. The fibers extracted from the stem of medicinal plant Derris scandens have the properties comparable to that of existing natural fibers, thus, suggesting it to use as a highly promising reinforcing agent alternative to synthetic fibers in polymer matrix composites.

Integrated Computational Material Design for PMC Manufacturing with Trapped Rubber.

As the use of continuous fiber polymer matrix composites expands into new fields, there is a growing need for more sustainable manufacturing processes. An integrated computational material design framework has been developed, which enables the design of tailored manufacturing systems for polymer matrix composite materials as a sustainable alternative to achieving high-quality components in high-rate production. Trapped rubber processing achieves high pressures during polymer matrix composite processing, utilizing the thermally induced volume change of a nearly incompressible material inside a closed cavity mold. In this interdisciplinary study, the structural analysis, material science and manufacturing engineering perspectives are all combined to determine the mold mechanics, and the manufacturing process in a cohesive and iterative design loop. This study performs the coupled thermo-mechanical analysis required to simulate the transients involved in composite manufacturing and the results are compared with a previously developed test method. The internal surface pressure and temperatures are computed, compared with the experimental results, and the resulting design process is simulated. Overall, this approach maintains high-quality consolidation during curing while allowing for the possibility for custom distributions of pressures and temperatures. This can lead to more sustainable manufacturing by reducing energy consumption and improving throughput.

Recycling carbon and glass fiber polymer matrix composite waste into cementitious materials

Recycling options for fiber polymer matrix composites (FPMCs) are limited since they typically cannot be re-used or re-processed. One source of FPMCs is the utility industry, which is increasingly using hybrid carbon and glass FPMC core high voltage (HV) conductors for energy transmission. As there are currently no recycling methods for these composite cores, we investigated if hybrid carbon and glass FPMC waste could be recycled as an admixture for cementitious materials in order to improve their properties for seawater applications. We assessed the compression strength of ordinary Portland cement (OPC) with 6% wt of various FPMC admixtures before and after accelerated salt-water aging. The experimental part of this research was strongly supported by molecular dynamics simulations (MD) to examine the effect of FPMC admixtures on moisture diffusion in OPC. It was established that recycled finely ground FPMC admixtures can provide a benefit to cementitious materials by decreasing void content and slowing the diffusivity of corrosive compounds such as salt water.

WITHDRAWN: Electret behavior and electret-based self-powering and self-sensing performance of carbon fiber polymer-matrix and carbon-matrix structural composites

WITHDRAWN: Electret behavior and electret-based self-powering and self-sensing performance of carbon fiber polymer-matrix and carbon-matrix structural composites

The Effect of Moisture on the Properties of Glass Fiber Polymer Matrix Composites with MoS2 and CaCO3

The mechanical properties and water absorption behavior of a pure glass fiber reinforced epoxy matrix and a glass fiber reinforced epoxy filled composites immersed into a tap water were investigated. The main purpose of this experiment is addition of two different powdered fillers (CaCO3 and MoS2) into the epoxy matrix and comparing the properties of pure GFRP and filled GFRP. The composites specimens with fillers absorb less water when compared to pure GFRP specimens at room temperature. Water absorption curves and equilibrium moisture content were determined. The composites exhibit a positive deviation from the Fickan’s law with the addition of fillers into the matrix. The influence of water uptake has significant effect on the reduction of mechanical properties. It is observed that 3% filled MoS2 in epoxy matrix has less uptake of water and the tensile strength decreased is 3% , flexural strength decreased up to 18% and shear strength is 42% decreased when compared to CaCO3 filled composites and unfilled glass fiber reinforced polymer composite.

Hyperbranched Polymers in Modifying Natural Plant Fibers and Their Applications in Polymer Matrix Composites-A Review.

Natural plant fibers have been widely used in the agricultural and forest industries, and even in the automobile industry, especially for producing fiber reinforced polymer matrix composites. However, the low mechanical properties of composites remain the key problem in the applications. A hyperbranched polymer has lots of advantages such as low viscosity, high reactivity, and so on. Multireactive end groups of hyperbranched polymers are ideal for modifying natural plant fibers to achieve better interface bonding between a fiber and resin matrix. This manuscript reviews some research advances in hyperbranched-polymer-modified natural plant fibers and summarizes the applications of the modified fibers in polymer matrix composites with a particular focus on the chemical modification of fibers and interface bonding.

Effect of fiber lay-up configuration on the electromagnetic interference shielding effectiveness of continuous carbon fiber polymer-matrix composite

Continuous carbon fiber polymer-matrix multifunctional structural composites capable of electromagnetic interference (EMI) shielding are needed for electronics and radiation sources. The laminate's fiber lay-up configuration affects the shielding effectiveness, as shown in this work for unmodified conventional carbon fiber polymer-matrix composite laminates with high-strength PAN-based carbon fiber and a polyamide thermoplastic matrix. The radiation is normal-incidence unpolarized plane wave, as commonly used. The shielding is dominated by absorption rather than reflection – more so for crossply composites than unidirectional composites. Due to the electrical conductivity longitudinal-to-transverse ratio of 930 for a lamina, the absorption-loss/thickness longitudinal-to-transverse ratio is 30 at 1.0 GHz. This factor of 30 means that the contribution of the fibers transverse to the electric field to absorption is negligible compared to that of the fibers parallel to the electric field. The ratio of absorption-loss/thickness for the crossply composite to that for the unidirectional composite with the same number of laminae is ∼4, and the ratio of the reflection loss for the crossply composite to that for the unidirectional composite is ∼2. The values of these ratios are consistent with electromagnetic theory for unpolarized radiation. This work strengthens the science base for the design of continuous fiber composites for shielding.

First report of capacitance-based self-sensing and in-plane electric permittivity of carbon fiber polymer-matrix composite

Capacitance-based damage self-sensing and the in-plane electric permittivity of continuous carbon fiber polymer-matrix composite are unprecedentedly reported. Capacitance-based self-sensing is advantageous over previously reported electrical-resistance-based self-sensing in not needing intimate electrical contacts and that two (rather than four) contacts suffice. Using a 220 × 220-mm2 unidirectional one-lamina polyamide-6-matrix composite, the capacitance (2 kHz) is measured in the through-thickness and in-plane directions using 25 × 25-mm2 aluminum-foil electrodes that are sandwiching and coplanar, respectively. Due to the composite's conductivity and the LCR meter's limitation, a dielectric film (adhesive tape) is positioned between electrode and specimen. In practice, this film can be the paint on the composite. Judiciously positioned artificial damage (1.1-mm diameter through-holes) causes the through-thickness capacitance to increase monotonically and the in-plane capacitance to decrease monotonically with increasing damage, due to the effect of the damage on the fringing electric field. The relative permittivity is 2160 ± 510 and 1640 ± 330 for the longitudinal and transverse directions, respectively, with anisotropy 1.3. The DC resistivity is 0.0072 ± 0.0004 and 10.9 ± 0.9 Ω cm in the longitudinal and transverse directions, respectively, with anisotropy 1500. The conductivity controls the current spreading, while the high permittivity provides the capacitance effect. The resistivity anisotropy causes the dependence of the capacitance-based sensing on the fiber orientation.