Fiber Reinforced Polymer Matrix Composites Research Articles

Fabrication and Characterization of Natural Fiber-Polymer Composites for Prosthesis Socket Application

ABSTRACT A natural fiber-reinforced composite from a locally available false banana plant is developed for a prosthesis socket application. Four batches of composite samples are fabricated by arranging the longitudinal uniformly distributed unidirectional false banana fibers in four orientations (0°, 90°, ±45°, 0°/90o). The composites’ mechanical and physical properties, such as tensile strength, compression strength, flexural strength, impact resistance, and the effect of chemical treatment on water absorption, are investigated. The results are compared with E-glass fiber-reinforced polymer matrix composite. The false banana fiber-polymer composites with a 0° fiber orientation have a tensile strength of 86.81 MPa, less than 9% lower than E-glass-fiber composites (95.44 MPa), and an impact resistance of 6.25 J, 10% higher compared to the E-glass fiber polymer composites (5.70 J). In addition, the treated false banana fiber-polymer composite absorbed 70% less water than the untreated false banana fiber-polymer composite. It is observed that the fiber treatment has increased the polymer–fiber interaction and the interface strength of the false banana fiber-polymer composites.

A review on gas permeability of polymer matrix composites for cryogenic applications

Fiber-reinforced polymer matrix composites are increasingly considered for lightweight cryogenic pressure vessels due to their excellent combination of tailorability, specific mechanical properties, and relatively low coefficients of thermal expansion. However, significant challenges must be overcome to fully utilize PMCs for cryogenic fuel tanks in terms of transverse microcracking and subsequent permeation of cryogenic fuel. Gas permeation and microcrack densities of cryogenically cycled composites are highly influenced by their layup, ply thickness, load case, and manufacturing defects like voids and resin rich zones. There has been a significant amount of research on measuring gas permeation of composites fatigued under pure thermal or uniaxial thermo-mechanical stresses. However, results demonstrate that the gas permeability should be measured under biaxial thermo-mechanical stresses to properly gauge the leakage characteristics of damaged composites. This paper summarizes the results from over a hundred papers on the key parameters that influence the gas permeability of composites, appropriate testing methods to cycle composites for permeability measurement, methods to limit the evolution of transverse microcracks, and materials traditionally used for the fabrication of all-composite cryogenic fuel tanks. Thin plies and nanofiller-toughening of the matrix have been shown to provide significant improvements in transverse microcrack suppression within cryogenically cycled composites.

Impact Performance Improvement of Multiscale Hybrid Fiber Reinforced Polymer Composites with CNT

Improving the interface properties of carbon nanotubes increases the mechanical performance of fiber-reinforced polymer matrix composites. Studies on different fiber types and different polymer matrix materials present promising results in literature. The effect of carbon nanotube (CNT) additives on impact performance of fiber reinforced polymer matrix composites produced by vacuum infusion method and drop weight impact test applied. Glass and carbon 1 m2 fiber fabrics were divided into 9 equal square pieces and placed on top of each other to make them multi-layered structure. Fiber reinforcements were produced using vacuum infusion method with epoxy resin. 0.5% of the total composite weight was added to CNT with same production parameters and intraply hybrid composite containing glass, carbon and aramid fibers was also produced. Samples were produced from the composite plates and the drop weight impact test was performed with 50 J impact energy in accordance with ASTM D7136 standard. While this increase could be observed in glass fiber and carbon fiber reinforced composites, the impact energy absorption performance in carbon fiber reinforced composite increased more than 100%. CNT increased the impact performance of multi-layer fiber reinforced polymer matrix composites.

Through‐thickness tensile characterization and analysis of fiber‐reinforced polymer composites using digital image correlation and finite element modeling

AbstractDigital image correlation (DIC) and finite element analysis (FEA) are used to assess the cylindrical spool‐shaped ASTM D7291 and I‐beam‐shaped specimens for through‐thickness (TT) mechanical characterization of thick (~25 mm) fiber reinforced polymer matrix composites. The composites are made of E‐glass woven fabrics reinforcing a vinyl ester matrix. DIC full‐field measurements and FEA showed a rather uniform strain distribution within the gage section of the ASTM D7291 specimen. However, strain concentrations are revealed at the bondlines between the end‐tabs and the test specimen, in addition to strain gradients at the curved section of the specimen. DIC‐measured and FEA‐predicted strain fields of the I‐beam specimens exhibited a region of uniform strain distribution within the gage section larger than that of the ASTM D7291 specimen. Nevertheless, high stress concentrations at the fillet (curved flange‐to‐web transition) regions and some amount of web bending occur in the I‐beam specimen. Beyond providing the TT mechanical properties of the E‐glass woven/vinyl ester composites, the current work discusses advantages and caveats of both promising specimens, providing quantifications of stress concentration factors and length of zones were strains and stresses may be considered uniform.Highlights Stress/strain distributions of through‐thickness tensile specimens are evaluated. The main drawback of the spool‐shaped specimen is adhesive failure. The modified I‐beam specimen shows acceptable stress concentration factors. The modified I‐beam is adequate for strength and Poisson ratio characterization. I‐beam specimens are easier to manufacture and do not require adhesive joints.

Composite Medical Tabletops Made of CFRP with Different Cross-Sections: Numerical Analysis and Laboratory Testing.

This paper presents the results of laboratory tests of CFRP (carbon fiber-reinforced polymer) laminates, which allowed the development of numerical material models. The obtained data were used in a further stage to perform numerical simulations of four variants of medical tabletops, differing, among other features, in the shape of the cross-section. Maximum deflections and effort in the composite material were analyzed. The final step was to perform a laboratory test for one of the tabletop versions, the results of which confirmed the correctness of the numerical calculations. This work is aimed at both researchers and designers involved in the practical application of fiber-reinforced polymer matrix composites.

Validation of large area capacitive sensors for impact damage assessment

Impacts in fiber-reinforced polymer matrix composites can severely inhibit their functionality and prematurely lead to the composite’s failure. This research focuses on determining the efficacy of a novel capacitive sensor, termed as the soft elastomeric capacitor (SEC), to monitor the magnitude of out-of-plane deformations in composites. This work forwards the development of a sensing skin that can be used as an in situ monitoring tool for composites. The capacitive sensor can be made to arbitrary sizes and geometries. The sensor is composed of an elastomer composite that measures strains experienced by the material it is bonded to. The structure of the sensor, fabricated to function as a parallel plate capacitor, responds to impacts by transducing strains into a measurable change in capacitance. In this work, the SECs are deployed on randomly oriented fiberglass-reinforced plates with a polyester resin matrix. The material is impacted at various energy levels until the monitored composite material reaches its yielding point. The behavior of the sensor in impact detection applications below the proof resilience shows little to no change in the capacitance of the sensor. As the impacts surpass this yielding point, the sensor responds linearly with induced change in the area. The sensor performed within the expectations of the proposed model and demonstrated the efficacy of the proposed large-area sensor as a damage quantification tool in the structural health monitoring of composites.

Response of trigger type to crash box energy absorption performance

In this study, carbon fiber reinforced polymer matrix composites were produced to investigate the trigger effect on energy absorption performance. Production was carried out by vacuum infusion method. Three types of trigger geometry were opened on the composite crash boxes produced and a comparison sample without trigger was prepared. The quasi-static compression tests of these four different samples were carried out and the energy absorption performances of the samples were evaluated with the obtained data. In addition, the damages of the samples were examined, and it was revealed how they changed with the trigger. Accordingly, the sample described as S-2, and the triggered sample, which consists of four symmetrical slits downwards from its upper surface, exhibited the best performance.

Influence of the stacking on mechanical and physical properties of jute/banana natural fiber reinforced polymer matrix composite

Influence of the stacking on mechanical and physical properties of jute/banana natural fiber reinforced polymer matrix composite

Mechanical Performance and Failure Analysis of a 3D-Printed "Continuous Layer-Lattice Layer-Continuous Layer" Sandwich Structure.

Sandwich structures are engineered with continuous layers surrounding the inner lattices, which combines the advantages of the high strength of the continuous layer and the light weight of the lattice layer. They are widely employed in weight-critical energy-absorbing engineering fields such as aerospace, automobile, and robotics. However, the application of sandwich structures made of polymer matrix composites is still limited due to lack of essential performance investigation and adequate reference data. The following innovative works are accomplished in this paper: (i) Continuous long glass fiber (CGF) is employed within the continuous layer of the sandwich structure, with composite short carbon fiber/polyamide (SCF/N) applied within the lattice layer. (ii) Sandwich structures with different cell types and orientations of the lattice infills are designed and prepared by additive manufacturing. (iii) The basic mechanical properties of the sandwich structures, i.e., the bi-directional tension/compression compound performance, failure modes and mechanisms in characteristic directions, are analyzed systematically. (iv) The effects of geometric features on the three-point bending properties of L-shaped sandwich structures are investigated and compared with those of pure SCF/N structures. The results show that the bending resistance per unit weight was up to 54.3% larger than that of pure SCF/N, while the weight could be decreased by 49%, and the bending flexibility before fracture could be increased by 44%. These studies contribute fundamental research data to the application of sandwich structures prepared by fiber reinforced polymer matrix composites.

Recent Progress on Moisture Absorption Aging of Plant Fiber Reinforced Polymer Composites.

Plant fiber reinforced polymer matrix composites have attracted much attention in many industries due to their abundant resources, low cost, biodegradability, and lightweight properties. Compared with synthetic fibers, various plant fibers are easy to obtain and have different characteristics, making them a substitute for synthetic fiber composite materials. However, the aging phenomenon of composite materials has been a key issue that hinders development. In natural environments, moisture absorption performance leads to serious degradation of the mechanical properties of composite materials, which delays the use of composite materials in humid environments. Therefore, the effects of moisture absorption performance of plant fiber composite materials on their mechanical properties have been summarized in this article, as well as various treatment methods to reduce the water absorption of composite materials.

Automatic defect detection in fiber-reinforced polymer matrix composites using thermographic vision data

The detection of internal defects, not visible to the naked eye from the outside of materials, using non-destructive testing (NDT) are increasingly requested by industrial processes. This study proposes a novel methodology for acquisition and processing of images from a thermographic camera using computer vision methods to test composite materials made of a polymer matrix reinforced with glass, carbon, and kevlar fibers. The image is acquired while cooling the sample, following a suggested procedure. The processing methodology is divided into three steps, image pre-processing, image processing, and data post-processing. In image preprocessing, filters are applied to improve image quality, and methods are proposed to segment and identify the region of interest. In image processing, a blob analysis method is suggested for defect identification, isolation and characterization. A data analysis method is proposed for the post-processing step to characterize the defects identified in the previous step. Samples with known defects in terms of size, geometry, and location were used to test the developed system. The system showed high performance, achieving 98% accuracy, and suitability for defect detection larger than 0.5 mm in thickness and 600 mm2 in area. The experimental results showed that the algorithm did not detect any false positives, and that the type of reinforcement used in the analyzed samples had no influence on the results. On the other hand, the depth of the delaminations had an influence on the pixel intensity contrast of the defect region, and its instant of maximum contrast. The lesser the depth of the defects detected, the higher the value of their intensity and the shorter the instant of maximum contrast.

Laser-induced heating, property changes, and damage modes in carbon fiber reinforced polymer matrix woven composites

Despite numerous efforts to understand mechanical damage in carbon fiber reinforced polymer matrix composites, there are minimal experimental and computational efforts that incorporate temperature effects on mechanical performance of composites. Recent studies have shown temperature changes can be readily monitored and predicted under relatively low heat fluxes. The present study augments such prior work by exploring effects of higher heat fluxes and increased heating rates. Plain-woven composites with T650 carbon fibers in a bismaleimide 5250-4 matrix were heated with a continuous wave laser (3.0 cm diameter flat-top beam profile at 1.0692 μm). Laser powers and durations were designed to reach temperatures near, and exceeding, matrix decomposition temperatures. Three duplicates of specimens were irradiated with four powers and two durations, yielding an irradiance range of 4.2 – 12.7 W/cm2. Resulting spatial and temporal temperature changes were measured with calibrated infrared cameras for both composite surfaces. Post-test surface photography and X‐ray CT scans were used to assess morphology changes and damage characteristics. Two key findings are reported herein: (i) delamination events dramatically impacted thermal transport, and (ii) TGA data and appropriate kinetic models can be used to account for temperature- / rate- dependent thermal responses and damage behaviors in the composites.

Experimental investigation on mechanical properties and water absorption capacity of novel polyester-wool-glass fibre-reinforced hybrid polymer matrix composites

Experimental investigation on mechanical properties and water absorption capacity of novel polyester-wool-glass fibre-reinforced hybrid polymer matrix composites

Investigation of dynamic properties of GLARE and CARALL hybrid composites: Numerical and experimental results

Fibre metal laminate (FML) composites are hybrid structures made of various metal sheets and fibre reinforced polymer matrix composites. These materials are preferred in the aircraft, automobile, and aerospace industries due to their high performance. Therefore, it is crucial to examine the vibration behaviour in the design process. In this study, the vibration behaviours of FMLs are examined numerically and experimentally. Firstly, the governing equations of the FML plate are determined based on classical plate theory. The generalized differential quadrature method (GDQ) is used in numerical analysis. Then, to prove the accuracy of the numerical model, the natural frequencies are compared with the experimental results. It is seen that the numerical results are in good agreement with the experimental results. Finally, the effects of material properties, geometry, and different boundary conditions on the dynamic properties of the FML composites are investigated. The results indicate that as the number of aluminium layers in the structure increases, natural frequencies are also significantly affected. When the Al layers are moved from the surface to the centre, it causes a reduction in the first natural frequencies of the structure. Morever, the boundary conditions substantially impact the natural frequency of the FML plates.

Fractographic analysis of composite joints under cryogenic conditions

Fiber-reinforced polymer matrix composites are often alternative materials for aerospace structures applications where high strength and stiffness at low weight are mandatory design requirements. However, there are still open issues related to thermal effects on composite parts' mechanical properties and fracture behavior, particularly under cryogenic conditions. This work aims to investigate the fracture aspects of carbon fiber composite joints made with co-curing, co-bonding, and secondary bonding technologies when subjected to cryogenic conditions. A detailed study was carried out on their mechanical performance under Mode I and Mixed Mode I/II loading by performing interlaminar fracture tests at −54 °C. Microscopy techniques were applied to better understand the failure mechanisms observed for each bonding technology. The manufacturing process has a direct influence on the crack propagation of the laminates at cryogenic temperature. The post-cure process results in a brittle behaviour for CB and SB composite joints tested at cryogenic temperature leading to significant reductions in the fracture toughness values. The CC composite joints exhibited a tougher behaviour in comparison to CB and SB composite joints. This is mainly due to the fact that these joints are not post-cured and the presence of an interlayer that delays crack propagation.

Phase-field fracture modeling for unidirectional fiber-reinforced polymer composites

In the present work, a phase-field fracture model is developed to create an experimentally validated, physically motivated, and computationally tractable framework to predict the orientation-dependent complex fracture response of the unidirectional fiber-reinforced polymer matrix composites (PMC). The damage mechanism in PMC is many-fold, such as matrix micro-cracking, fiber breakage or pullout, fiber debonding, and delamination. The progressive damage and failure in the composite can be attributed to the competition of all these different damage mechanisms individually or in concert, depending on fiber volume fraction and orientation of the plies. Moreover, other important factors at the constituent level, such as viscoelasticity or plasticity of the matrix, can significantly influence the constitutive behavior of the composite. In this work, a homogenized, coupled thermo-mechanical constitutive model is developed considering the viscoelasticity of the polymer matrix for the fiber-reinforced PMCs. Subsequently, a phase-field fracture model is adopted to capture the essential damage mechanisms as matrix cracking and fiber pullout/breakage for unidirectional composite lamina. The phase-field variable considers an anisotropic tensorial term in its gradient to account for the orientation-dependent fracture of fiber-reinforced PMC. The model is numerically implemented by writing an ABAQUS user-element subroutine (UEL). The model can predict the direction-dependent damage propagation and the final load-deformation response at fracture in commercially acquired unidirectional glass-fiber-reinforced epoxy composites at different fiber orientations in reasonable agreement with the experiments. Based on the decoupling of the driving energies the model can also identify the dominant damage mechanism among the two such as fiber breakage or matrix cracking, for a given fiber orientation. Simulations are also conducted to validate the model predictions for carbon-fiber reinforced epoxy lamina with available experimental data in the literature.

Effect of Alternating Hybridisation of Fibres on the Physico - Mechanical Behaviour of Composite Materials

Abstract The performance/weight ratio of fiber reinforced polymer matrix composites makes them the material of choice for structural applications in many fields such as aerospace, aeronautics, automotive and civil engineering...etc. In polymer matrix composites, the fibers used as reinforcement are mainly synthetic fibers such as carbon and/or glass fibers. To ensure the low cost of using fiber-reinforced materials in motor vehicles, it is proposed to selectively incorporate carbon fibers to enhance glass fiber composites along the roadway, and to enhance glass fiber composites along the main load path. For this purpose, we conducted a behavioral study of hybrid epoxy thermoset polymer matrix laminates to highlight the influence of alternate hybridization of glass and carbon fibers on the physical-mechanical behavior of the materials.The results obtained show that the alternated hybridation of the fibers has a significant influence on the tensile properties; and it affected the density, hardness and flexural properties significantly.

Effect of fiber layer formation on mechanical and wear properties of natural fiber filled epoxy hybrid composites

Natural fiber-reinforced polymer matrix composites are gathering significance in future trend applications such as automotive, aerospace, sport, and other engineering applications due to their superior enhanced mechanical, wear, and thermal properties. Compared to synthetic fiber, natural fiber is low adhesive and flexural strength properties. The research aims to synthesize the epoxy hybrid composites by utilizing the silane (pH = 4) treated Kenaf (KF) and sisal fiber (SF) as layering by uni, bi, and multi-unidirectional via hand layup techniques. Thirteen composite samples have been prepared by three-layer formation adopted with different weight ratios of E/KF/SF such as 100E/0KF/0SF, 70E/30KF/0SF, 70E/0KF/30SF, 70E/20KF/10SF, and 70E/10KF/20SF respectively. The effect of layer formation on the tensile, flexural, and impact strength of composites is studied by ASTM D638, D790, and D256 standards. The unidirectional fiber layer formed (sample 5) 70E/10KF/20SF composite is found maximum tensile and flexural strength of 57.9 ± 1.2 MPa and 78.65 ± 1.8 MPa. This composite is subjected to wear studies by pin-on-disc wear apparatus configured with a hardened grey cast-iron plate under an applied load of 10, 20, 30, and 40 N at different sliding velocities of 0.1, 0.3, 0.5, and 0.7 m/s. The wear rate of the sample progressively increases with increasing load and sliding speed of the composite. The minimum wear rate of 0.012 mg/min (sample 4) is found on 7.6 N frictional force at 0.1 m/s sliding speed. Moreover, sample 4 at a high velocity of 0.7 m/s with a low load (10 N) shows a wear rate of 0.034 mg/min. The wear-worn surface is examined and found adhesive and abrasive wear on a high frictional force of 18.54 N at 0.7 m/s. The enhanced mechanical and wear behavior of sample 5 is recommended for automotive seat frame applications.

A novel damage evaluation of CFRPs under mode-I loading by using multi-instrument structural health monitoring methods

Mode-I fracture toughness test provides valuable information in the thickness direction of fiber reinforced polymer matrix composites. However, damage propagation under mode-I loading is dependent on the configuration of reinforcing material of the laminate. Understanding the damage types and their growth rate in mode-I fracture toughness test is a vital factor to obtain material allowable for safe design. In this study, mode-I tests are conducted on unidirectional, and twill woven carbon fiber reinforced polymer composite laminates. A new approach is proposed to interpret passive infrared thermography results based on correlating acoustic emission and thermography results in time whereby thermal activities can be classified into two main groups corresponding to matrix and fiber dominant failure types. It is demonstrated that matrix and fiber dominant failures lead to thermal activities with line-wise and point-wise form, respectively. Results show that four different damage types can be seen for mode-I fracture of both laminates. The temporal observations during thermoelastic cooling of the materials show that twill woven laminate releases relatively higher energies due to matrix dominant damage developments which means this configuration type is more prone for delamination failures.

Low velocity impact behavior of auxetic CFRP composite laminates with in-plane negative Poisson’s ratio

Introducing auxeticity or negative Poisson’s ratio is one potential solution to mitigate the low velocity impact damage of fiber reinforced polymer matrix composites, which can be achieved by tailoring the layup of an anisotropic composite laminate. This study aims to investigate the effect of laminate-level in-plane negative Poisson’s ratio on the low velocity impact behavior of carbon fiber reinforced polymer (CFRP) matrix composites using numerical simulations. The layups of the auxetic composites that allow them to produce negative Poisson’s ratios are identified based on the Classical Lamination Theory and verified through fundamental coupon-level experimental tests. To ensure meaningful comparisons, the non-auxetic counterpart composites are designed by allowing them to produce positive in-plane Poisson’s ratio while closely matching the longitudinal effective modulus of the auxetic laminate. The simulation results indicate that the auxetic laminates suffer smaller (12.6% on average) delamination area in top and bottom interfaces, much smaller (38% on average) matrix compressive damage in the top and bottom plies, and smaller (14.6% on average) fiber tensile damage area in each ply of the laminate at relatively higher impact energies (5 and 8 J).