Fabric-reinforced Epoxy Research Articles

Experimental study on multiple self-healing and impact properties of 2D carbon fiber fabric-reinforced epoxy composites with shape memory properties

Fiber-reinforced thermoset polymers are widely used in aerospace as a material with excellent performance. However, for the low-velocity impact damage to which they are most susceptible, existing repair methods are difficult to maintain the aerodynamic performance of the components (back to its pre-damage shape) after repair. In this study, the multiple impact deformation recovery, internal damage healing, and post-repair impact properties of epoxy-PCL (ε-caprolactone) 2D carbon fiber fabric-reinforced polymers with shape memory and self-healing properties were investigated. The material is manufactured using a hot press tank-prepreg process, curing at 160 degrees for 3.5 hours at 6 atmospheres. The results show that the incorporation of thermoplastic PCL into the composite matrix can enhance the self-healing ability and impact resistance of the material. Composites after lower energy impacts retain their structural integrity and mechanical properties after healing. Materials can recover effectively from a single impact, but repeated impacts can lead to more extensive damage, which makes healing more difficult and causes a decrease in Healing efficiency. The shape memory effect of composites can restore plastic deformation caused by impact, which highlights the potential of shape memory smart composites for aerospace applications.

Experimental characterization of hemp woven fabric reinforced epoxy resin composites produced without heat treatment

Experimental characterization of hemp woven fabric reinforced epoxy resin composites produced without heat treatment

Effect of Fiber Stacking Sequence on Mechanical Property of Polymeric Composite through VARTIM Method and Metallographic Examination

Because of higher specific modulus/strength, lower weight, good corrosion resistance with design flexibility and easy production, carbon fiber reinforced epoxy composites are widely used for many structural applications. Glass woven (plain) and carbon fabric (plain) were studied. Thus, glass fabric-reinforced epoxy composites (GFRCs) and carbon fabric-reinforced composites (CFRCs) were fabricated throughVacuum Assisted Resin Transfer moulding (VARTM) methodology. Firstly, manufacturing unit/control system, preparation stages and some elements used in manufacturing the epoxy based composites are reviewed. Then, effects of stacking sequence of fibers on mechanical properties were investigated and a comparison was made on two types of fabrics on hardness/deformation depth through Stereo Microscope (SM). The experimental results exhibited that the hardnesses measured were around 40.6 HB and 52.4 HRB for GFRP and CFRP, respectively. Improvements in carbon fiber were about 29% in comparison to glass fiber. Further, both hybrid composites made from glass and carbon fiber, the hardnesses values were reduced. In case of C2/G2/C2 hybrid composites, reduction rate was about 9.3% in comparison to C6 fiber reinforced laminate composite. Moreover, it is clearly revealed that there were extensive deformation regions reflecting the white areas because top layer was in G2/C2/G2 samples, but there was no such a white area in C2/G2/C2 composite.

Tribological properties of CNT-filled epoxy-carbon fabric composites: Optimization and modelling by machine learning

Polymer matrix composites reinforced with fibers/fillers are extensively used in several tribological components of automotive and boating applications. The mechanical performance of polymer composites improves by incorporating nanofillers as secondary reinforcement. The present research work fabricated carbon fabric-reinforced epoxy composites using the hand layup. The carbon fabric-reinforced polymer composites were fabricated with 0.1 wt%, 0.2 wt%, and 0.5 wt% of carbon nanotubes (CNT) fillers as secondary reinforcement. Tribological properties of carbon fabric-reinforced epoxy composites filled with CNT have been carried out using a pin‐on‐disc method. Adding fillers significantly improves the tribological behaviour of the carbon fabric-reinforced epoxy composites by reducing wear rate and coefficient of friction. The large surface area of interaction due to the higher aspect ratio of CNT shows improved adhesion between epoxy matrix and carbon fabrics. It improves the various mechanical and tribological characteristics of composites—also, an analysis of worn surfaces is carried out to analyze the wear mechanisms using scanning electronic microscopy. The research employs a combination of experimental analyses and machine learning (ML) techniques to explore the wear resistance, hardness, and predictive modeling of volume loss in the composites. The hyperparameter fine-tuning of ML algorithms, including Random Forest (RF), k-Nearest Neighbors (KNN), and XGBoost, demonstrates superior predictive capabilities, particularly with RF. The study bridges material science, ML, and practical applications, contributing valuable insights for developing advanced composite materials.

Thermal and Colorimetric Parameter Evaluation of Thermally Aged Materials: A Study of Diglycidyl Ether of Bisphenol A/Triethylenetetramine System and Fique Fabric-Reinforced Epoxy Composites.

The main modifications of thermal and colorimetric parameters after thermal aging of DGEBA/TETA system (plain epoxy) and fique-fiber woven fabric-reinforced epoxy composites are described. As a preliminary study, thermal analysis was carried out on epoxy matrix composites reinforced with 15, 30, 40 and 50% fique-fiber woven fabric. After this previous analysis, the 40% composite was chosen to be thermally aged, at 170 °C. Three exposure times were considered, namely, 0, 72, 120 and 240 h. Samples were studied by thermogravimetric analysis (TGA), differential thermal analysis (DTA), differential scanning calorimetry (DSC), thermomechanical analysis (TMA) and colorimetry analysis. Significant color changes were observed after thermal aging combined with oxidation. It was also found that the thermal behavior of the plain epoxy showed greater resistance after thermal exposure. By contrast, the composites were more sensitive to temperature variations as a result of thermal stresses induced between fique fibers and the epoxy matrix.

Tribological Performance of Bamboo Fabric Reinforced Epoxy Composites

AbstractBamboo fiber is one of the strongest natural fibers with high strength‐to‐weight and stiffness‐to‐weight ratios and can be used economically for manufacturing fiber‐reinforced composites. In this paper, bamboo fabric‐reinforced epoxy composite is manufactured and its tribological properties for load‐bearing applications are investigated. Sliding wear tests are conducted using a linear reciprocating tribometer and the effect of dry and lubricated contact conditions, applied load, sliding speed, temperature, and woven fabric direction on the coefficient of friction and wear rate are investigated. A scanning electron microscope is used to define the wear mechanisms at room and elevated temperatures. It is observed that the fabric orientation influences the mechanical and tribological performances of the composite material. Wear rate increases at higher loads and working temperatures; however, the effect of sliding speed is not remarkable, especially under lubricated contact conditions. The results present in this paper can be used for designing bamboo‐reinforced epoxy composites for load‐bearing applications, under different working conditions.

Mechanical Performance of Hybrid Graphene Nanoplates, Fly-Ash, Cement, Silica, and Sand Particles Filled Cross-Ply Carbon Fibre Woven Fabric Reinforced Epoxy Polymer Composites Beam and Column

The main goal of this study is to reduce the brittleness of a fibre-reinforced cement base structure when exposed to the effects of graphene nanoplates, fly ash, silica, sand, and cement fillers to better understand the effect of hybrid nano/micro particle fillers on the mechanical performance of cross-ply carbon fibre reinforced epoxy resin composites. A three-point bending test through the width was used to measure flexural strength. The impact tests Izod at low impact velocity and Charpy through the thickness were used to determine the dynamic fracture strengths of pre-cracked and non-cracked composite samples. Also, the compressive test method was used to measure the compressive strength of hybrid particles and short glass fibre-reinforced epoxy resin composite square and circular columns. The results show compressive strength and flexural strength. Izod impact energy, Charpy impact energy, and dynamic fracture toughness of hybrid nano/microparticle-filled fibre composites have higher values than virgin fibre composites due to the influence of graphene nanoparticles and perfect interface bonding between two dissimilar molecules of nano and microparticles, which improve the fracture toughness and absorb impact energy. Overall, the results indicate that molecules of nano/microparticle-filled carbon fibre and glass fibre-reinforced epoxy resin composites can be used in aggressive environments because of the improved mechanical properties in comparison to the virgin fibre composites. In addition, SEM micrographs clearly indicate that nano- and microparticles are resistant crack propagation and deboned of matrix fibres.

Preparation and properties of APP flame-retardant ramie fabric reinforced epoxy resin composites

Ramie fabrics (RFs) as natural fibers have shown promising potential in the field of fiber reinforced composites, but flammability of RFs limits their application in composites. In this study, ammonium polyphosphate (APP) was first coated on the surface of RFs, and then the flame-retardant RF reinforced epoxy resin composites were obtained. When the weight gain rate of APP in RFs was about 20 %, the limiting oxygen index of the flame-retardant composites reached 33.8 %, and achieved UL-94 V-0 rating. At the same time, the peak heat release rate and total heat release values of the flame-retardant composites were reduced by 26 % and 41 % respectively, and the total smoke production was reduced by 43.9 %. In terms of mechanical properties, the presence of APP had a certain negative effect on the internal compatibility of composites. In this work, the flame-retardant composites show excellent flame retardancy and provide a feasible solution to improve the flammability of natural fiber reinforced composites.

Construction of bio-based ramie fabric/epoxy resin composites with high flame retardant and mechanical performances

The development of bio-based polymers will be beneficial to reducing carbon emissions. The biobased fiber-reinforced biobased epoxy resin can prepare fully-biobased polymer composites. However, their flame retardation will become a challenging issue. Here, fire-retardant ramie fabrics surface-modified by ammonium polyphosphate (APP) and polyethyleneimine were integrated into an epoxy system followed by fabricating high-performance composites. Notably, the epoxy resin composite with 8.9 % flame retardant displays a UL-94 V-0 rating. Besides, EP/(MF-2) exhibits a remarkably decreased peak of heat release rate (285 kW/m2) in contrast to pristine fabric-reinforced epoxy resin composite (608 kW/m2) from the cone calorimeter test. The improved flame-retardant performance follows the mechanism of the catalytic dehydration and charring effect by phosphorus-containing acids from the degradation of APP. Furthermore, flexural strength of EP/(MF-2) increases by 29 %, compared with neat EP, indicating obvious reinforcement of ramie fabric.

Influence of Filler Materials on Wettability and Mechanical Properties of Basalt/E-Glass Woven Fabric-Reinforced Composites for Microfluidics.

This paper presents the development of novel hybrid composites in the presence of filler particles and manufactured using a proposed new fabrication technique. The hybrid composites were fabricated using a basalt and E-glass woven fabric-reinforced epoxy resin matrix combined with graphite powder nanoparticles. Six sets of samples were fabricated using the vacuum-assisted free lamination compression molding technique. After the fabrication, wettability, mechanical properties (tensile, flexural and impact properties) and moisture properties were evaluated. Surface morphology and chemical composition of the composite samples were examined using a scanning electron microscope (SEM) and spectroscopy. The obtained results showed that the use of filler materials in hybrid composites improves the properties of hybrid composites. Basalt/E-glass hybrid composites with 10% graphite material exhibited superior mechanical properties over the other composites, with high-quality, improved adhesion and surface morphology. Thus, novel composites with the combination of exceptional properties may be integrated in the design of flexible electronics and microfluidics devices as a structural layer of the system. High flexibility and good surface tension of the designed composites makes them attractive for using the thermal imprint technique for microfluidics channel design.

Influence of hBN and MoS2 fillers on toughness and thermal stability of carbon fabric-epoxy composites

Hexagonal boron nitride (hBN) and molybdenum disulfide (MoS2) fillers of 2 to 8 wt.% influence on toughness, microhardness and thermal stability of carbon fabric-reinforced epoxy composite (CFREC) reported. Mode-I, mixed-mode I/II toughness and microhardness of CFREC improved due to the addition of hBN and MoS2 separately upto 6 wt.% filler loading. The epoxy matrix in CFREC modified by hBN and MoS2 strengthens the matrix, deflects the crack path and resists delamination. Toughness reduced beyond 6 wt.% filler addition due to agglomeration and poor fiber-filler-matrix bonding as revealed by the surface morphology of the fracture specimen. Thermal analysis reveals decomposition temperature at 25% weight loss increased from 395 to 430 °C and 395 to 411 °C due to 4 wt.% MoS2 and 4 wt.% hBN addition to CFREC respectively. Impermeable characteristics of MoS2 and hBN fillers caused tortuous diffusion path for gas molecules and delayed thermal decomposition.

Buriti Fabric Reinforced Epoxy Composites as a Novel Ballistic Component of a Multilayered Armor System

Buriti Fibers extracted from the leafstalk of palm tree, Mauritia flexuosa, native to the Amazon region, have been investigated as a reinforcement of polymer matrix composites. Recently, the fabric made from buriti fibers was also studied as a possible reinforcement of epoxy composites. In particular, the preliminary results of a 10 vol% buriti fabric epoxy composite in a multilayered armor system (MAS) displayed a satisfactory backface signature (BFS) but the composite target was not able to preserve its integrity after the ballistic impact. This motivated the present work, in which we carry out a complete statistical investigation of the ballistic performance of 10, 20, and 30 vol% buriti fabric epoxy composites as a MAS second layer against 7.62 mm rifle ammunition. BFS, associated with the depth of penetration in a clay witness simulating a human body, disclosed values of 18.9 to 25 mm, statistically similar and well below the lethal value of 44 mm specified by the international standard. Absorbed energy in stand-alone ballistic tests of 163–190 J for armor perforation were also found to be statistically higher than 58 ± 29 J obtained for the conventionally applied synthetic aramid fabric. The 30 vol% buriti fabric composites maintained the integrity of the MAS second layer, as required for use in body armor. Failure mechanisms found for the 10 vol% and 20 vol% buriti fabric composites by macro analysis and scanning electron microscopy confirmed the importance of a higher amount such as 30 vol% in order to achieve effective ballistic protection.

Study of the fatigue behaviour of hybrid flax-glass/epoxy composites

This paper presents an experimental study of the fatigue behaviour of non-hybrid and hybrid twill flax and glass fabric-reinforced epoxy laminates. To this end, several plates of these composite materials were elaborated by the vacuum infusion process and three hybrid configurations were chosen. Specimens of these composite materials were subjected to tensile fatigue tests coupled with Acoustic Emission (AE) recording by considering two frequencies of 5 and 10 Hz with a loading level of 65%. The results from fatigue tests are deeply analysed to evaluate the fatigue loading effect on the stiffness degradation, hysteresis loops and damping ratio of the studied non-hybrid and hybrid composites. The obtained results show that the flax-glass hybridization improves the fatigue behaviour of the glass-epoxy laminate. In particular, the replacement of two internal glass layers with two flax ones reduces the loss of maximum stress by ∼13% and enhances the damping property by ∼60% at 10 Hz compared with the glass-epoxy laminate. On the other hand, the AE analysis allows identifying three classes of the recorded acoustic signals in all materials, which are attributed to the main damage mechanisms based on SEM observations.

Macroscale modelling of 3D-woven composites: Elasto-plasticity and progressive damage

There is a growing need across multiple industries for lightweight materials with improved material performance and reduced manufacturing costs. Composites with 3D-woven reinforcement could help fill this need. Their use however, requires the development of computationally efficient and industrially applicable material models to predict their non-linear behaviour. This work proposes a macroscale elasto-plasticity and damage model to capture the experimentally observed inelastic strains and stiffness reductions. The model is general, thermodynamically consistent and allows for various non-linear phenomena to be added and calibrated in a modular fashion depending on loading direction. Further it allows for a simplified parameter identification routine in which the damage and hardening laws are identified directly from experimental curves without the need for complex calibration routines.In order to demonstrate the applicability of the proposed macroscale model, focus is given to predicting the material response of a 3D glass fibre reinforced epoxy material system. The damage and hardening parameters are identified based on uniaxial tensile and in-plane shear experimental curves with unloading cycles. The model performance is validated against an off-axis tensile test with unloading cycles and shows good agreement to the experimental result.

A Study of the Flexural Properties of Jute Fabric Reinforced Epoxy Composite: Experimental and Uncertainty Analysis

ABSTRACT The variability in natural fiber composite properties has always been problematic due to the dispersion in their mechanical properties resulting from fiber misalignment, irregular crosssection, fiber length, and geometry, which impacts their reliability. This issue of reliability has greatly affected the selection process of natural fiber composites as opposed to the synthetic fiber counterparts when it comes to strength, stiffness, failure strains, and energy absorption criteria. Stiffness is one property which greatly depends on the span length and load-bearing capacity of the material, which makes it an important criterion during product design. In this study, flexural properties of the jute fabric composite were studied through experiment and uncertainty analysis using various distribution functions. Jute epoxy composite at 38% fiber volume fraction was fabricated, and samples were machined using abrasive water jet machining as per ASTM D7264 standard for bend test. The samples were experimentally tested for bending strength, modulus, and failure strains, and uncertainty analysis was done to further analyze their failure behavior. Experimentally tested samples showed multimode bending failure such as M(CAT) and M(TAB) as per ASTM D7264.

Influences of spacer monofilament distributions on mechanical properties of warp-knitted spacer fabric/resin composites

Warp-knitted spacer fabrics have a unique three-dimensional structure and excellent compressive properties. They can also be used as reinforcement and compounded with base material to obtain composites. In this paper, warp-knitted spacer fabrics with single-sided hexagonal mesh structure were prepared, and the spacer monofilaments were removed in a set ratio to analyze the effects of distribution patterns of them on the tensile and compressive properties of warp-knitted spacer fabrics. Warp-knitted spacer fabric-reinforced epoxy resin-based composites with various structures were prepared to investigate the compressive and bending properties. The results showed that the tensile properties of warp-knitted spacer fabrics were not significantly related to the distribution, but compression performance was correlated with the spacer monofilaments ratio ( n). Fabric-reinforced epoxy resin-based composites of sample no. 1 have the best compression performance, and the best performance in bending is sample no. 5. A different type of warp-knitted spacer fabric could be chosen for achieving the optimal configuration in specific application scenarios. This paper can provide theoretical implications for the application of warp-knitted spacer fabrics and fabric-reinforced epoxy resin-based composites.

EFFECT OF SALT-WATER AGING ON THE MECHANICAL PROPERTIES OF FLAX-WOVEN FABRIC-REINFORCED EPOXY COMPOSITES

In this investigation four varieties of plain derived-irregular basket-woven-flax fabric-reinforced epoxy (F-E) composites pre-treated with alkali and trimethoxymethylsilane (ATS) were prepared with a hand lay-up process by varying their weight fraction of fiber loadings (0; 25; 35; 45) w/%. A water-absorption test (salt water) as per ASTM D 570-98 was performed over the fabricated composites and studied its consequences on their static mechanical properties (such as tensile, flexural, impact and interlaminar shear strength) in accordance with the ASTM standards. The results revealed that salt-water-soaked ATS-treated F-E composites exhibited poorer mechanical properties than unsoaked ones. Moreover, this study elaborated the kinetics of water absorption and showed that the moisture-absorption rate depends on the weight fraction of fibre content. Furthermore, scanning electron microscopy (SEM) disclosed fiber splittings and severe damage at the fiber-matrix interface as experienced by soaked F-E composites.

Dynamic Mechanical Analysis of Thermally Aged Fique Fabric-Reinforced Epoxy Composites.

Dynamic mechanical analysis (DMA) is one of the most common methods employed to study a material’s viscoelastic properties. The effect of thermal aging on plain epoxy and a fique fabric-reinforced epoxy composite was investigated by comparing the mass loss, morphologies, and DMA properties of aged and unaged samples. In fact, thermal aging presents a big challenge for the high-temperature applications of natural fiber composites. In this work, both plain epoxy and fique fabric-reinforced epoxy composite were found to have different molecular mobility. This leads to distinct transition regions, with different changes in intensity caused by external loadings from time-aging. Three exponentially modified Gauss distribution functions (EMGs) were applied to loss factor curves of fique fabric-reinforced epoxy composite and plain epoxy, which allowed identifying three possible mobility ranges. From these results it was proposed that the thermal degradation behavior of natural fibers, especially fique fiber and their composites, might be assessed, based on their structural characteristics and mechanical properties.

Experimental Studies on Abrasion Wear and Thermal Characteristics of Plain Derived Flax Woven Fabric Reinforced Epoxy Composites

ABSTRACT Nowadays, natural plant fibers are being explored and employed for various industrial applications owing to their attributes such as low weight to strength ratio, cost effectiveness, biodegradability and environment-friendliness. In this work, alkali and trimethoxymethyl silane (ATS) treated plain derived irregular basket woven flax fabric-reinforced epoxy composites (F-E) namely 0-TFE (Neat epoxy), 25-TFE, 35-TFE and 45-TFE with 0, 25, 35 and 45 wt.% fiber contents respectively were prepared by compression molding at room temperature, and studied for their abrasive wear and thermal degradation characteristics as per the standard procedures. Abrasive test was performed on pin on disc with a track diameter of 80 mm (ASTM G-99-05) for varying applied load and different abrasive grits condition for a constant speed of the disc. Wear outcome revealed that wear loss, specific wear rate (SWR) and coefficient of friction (COF) were influenced by the combined effect of applied load and abrasive grits. The composite 45-TFE exhibited better tribological properties amongst the prepared lot. Furthermore, thermal analysis revealed that the fabricated F-E composites are sufficiently thermally stable for structural applications and ATS treated- plain derived flax woven reinforcement enhanced the thermal stability. Scanning electron microscopy (SEM) was used to understand the wear mechanisms of composites.

Effects of nano-Al2O3 and PTFE fillers on tribological property of basalt fabric-reinforced epoxy composites

ABSTRACT Effects of nano-Al2O3 and PTFE fillers on tribological behaviour of basalt fabric reinforced epoxy composite (BFRC) produced with a combination of molding and mixing method were studied by Taguchi L9 design. Microstructures and worn surfaces of composites were investigated by scanning electron microscopy. Regression equations were also developed for predicting wear and coefficient of friction. The results indicated that specific wear rate increased with increasing load and decreasing speed, but friction coefficient decreased with increasing speed, PTFE addition and medium load. In addition, wear rate of nano-PTFE was lower than that of nano-Al2O3 because of its microstructure. PTFE decreased the friction about 17%. Load was effective on the wear rate while speed was dominant on the friction. Moreover, multiple fiber fractures and large numbers of debris were dominated for BFRC while fiber debondings, fiber removals and debris agglomerations were effective for Al2O3, but fiber fractures and flake types of debris were responsible for PTFE.