Fabric Reinforced Epoxy Composites Research Articles

In‐plane compressive properties and failure mechanisms of modified three‐dimensional multi‐axial warp knitted fabrics reinforced composites at different temperatures

AbstractThree‐dimensional multi‐axial warp knitted (3D MWK) reinforced composites are important components of advanced structural composites. The interfacial bonding between fiber and matrix is key to achieving high mechanical properties. In this work, graphene oxide (GO) and poly(oxypropylene) diamines (D400) were grafted on glass fiber (GF) multi‐axial warp knitted (MWK) fabrics to construct a “flexible‐rigid” structure. The surface morphologies of GF were characterized by SEM and EDS. Then, 3D MWK‐reinforced composites were prepared based on four kinds of modified fabrics using the VARTM method. The in‐plane compression properties were obtained at different high temperatures and their failure modes were analyzed. The strain–stress curves showed that the composites exhibited brittle fracture modes. D400 and GO‐modified multi‐scale composites exhibited outstanding compression properties. The strength of the related composited was improved by 55.78%, 76.78%, 52.19%, and 56.78% compared to that of desized composite at 30°C, 60°C, 120°C and 150°C, respectively. The damage to D400‐GO modified and D400 modified composites was the most serious, where shear fracture modes were obvious in addition to layer debonding features. This protocol provides a potential strategy to manufacture of D400 and GO‐modified hierarchical reinforced composites.Highlights The modified 3D MWK glass fabrics based on poly(oxypropylene) diamines (D400) and graphene oxide (GO) were prepared. The compressive properties of 3D desized, D400‐, D400‐GO‐, and GO‐MWK fabrics reinforced epoxy composites were obtained and analyzed at different temperatures of 30°C, 60°C, 120°C, and 150°C. The failure mechanisms of 3D desized, D400‐, D400‐GO‐, and GO‐MWK fabrics reinforced epoxy composites at different temperatures were analyzed.

Influence of co-deposition modification on mode I and II interlaminar toughness of epoxy laminates interleaved with waste textiles using experimental measurement and finite element technique

Interlaminar delamination has been a persistent problem that restricts the ability of fiber reinforced laminated composites under applied load. The influence of polyethyleneimine-catechol (PEI-CCh) co-deposition modification on the mode I (GIC) and II interlaminar fracture toughness (GIIC) of plain glass fiber fabric reinforced epoxy composites (PGFRECs) were discussed using double cantilever beam (DCB) and end notch flexural (ENF) tests. It was found that interfacial properties of PET/epoxy and PET/cotton/epoxy interfaces were substantially improved after co-deposited modification, which laid a solid foundation for enhancing the resistance to interlaminar delamination. GIC and GIIC in platform of crack propagation greatly increased with the introduction of co-deposition layer. The fracture surfaces of delaminated failure specimens were observed by scanning electron microscope. The higher propagation fracture toughness for co-deposition modified PGFRECs is due to the anchoring effect of functional layer combining waste fabrics with epoxy matrix to provide favorable stress transfer channel prior to macroscopic crack formation. In regard to the delamination crack, new crack generation and bridge fiber failure mainly dominated the mode I crack extension process, while zigzag sections were particularly common for mode II fracture specimens.

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.

The Production and Characterization of Seashell Reinforced Epoxy Composite Material

In this study, it was aimed to examine the production, characterization and mechanical properties of epoxy matrix composites added with seashells collected from different coastal locations of the Mersin Region, which is a natural raw material. Natural seashells with different mass ratios were ground into different sizes and added into epoxy, the matrix material. By performing physical and chemical characterization of the produced composites, the next step is to analyze and produce the product with the best and most superior properties.

Experimental Investigations on Cylindrical GFRP Composite Pipes under Compression Loading

In a wide variety of aerospace applications have the mechanical properties of a thin cylindrical shell are important. Thin cylindrical shell structures are used to store a small and large quantity of fluids and solids. Glass Fabric reinforced epoxy composite is used to prepare the thin cylindrical pipes with different diameters and varying thickness of the composite pipes. The additives as glass flakes are added with 5%, 10% and 15% of the resin content in the matrix. The rolled composites specimens are prepared with the stainless steel (SS) mould. Experiments are test on Universal Testing Machine under lateral compression test to study the breaking load and compressive strength of the specimens. The failure modes are also observed.

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.

An Experimental Study on Drilling Behavior of Silane-Treated Cotton/Bamboo Woven Hybrid Fiber Reinforced Epoxy Polymer Composites.

Machining is considered to be an important post-manufacturing process. Evaluation of machinability of natural-fiber-reinforced composites is important owing to its wide application spectrum. Current experiments focus on the drilling parameters of cotton/bamboo woven fabric reinforced epoxy composites laminates using a solid twist drill. Composites were manufactured with 45 wt.% cotton/bamboo woven fabric in epoxy resin using a compression molding method. Drilling experiments were carried out in pillar-type drilling machine and the drilling characteristics, such as thrust force, were analyzed using four process parameters like spindle speed, feed rate, drill diameter, and silane-treated fabric. Drilling experiments were carried out using the Box-Behnken Experimental Design, and the recommended drilling characteristics were analyzed using quadratic models based on response surface methodology. It was observed from the results that the thrust force is low with small drill-bit diameter, higher cutting speed, and lower feed rate, according to the response surface analysis. Surface morphology of the drilled hole suggested that a better quality of hole can be obtained at lower feed rates.

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.

Flexural and flame retardance properties of multi-walled carbon nanotubes/glass fibre/epoxy hybrid composites

The effect of different multi-walled carbon nanotubes (MWCNTs) wt.% loading on the flammability, water absorption, thermal stability and flexural properties of glass fabric reinforced epoxy composites is reported in this paper. The pristine MWCNTs were dispersed in water, using arabic gum (GA) as a dispersing agent. Then, the suspension was sprayed onto the glass fibre (GF). Hybrid composites with and without MWCNTs were fabricated using hand lay-up and vacuum bagging techniques. Based on standard fire testings such as limiting oxygen index (LOI) and horizontal burning (UL94HB), it was observed that the composites were able to self-extinguish, even at low amounts of MWCNTs. Increase in the MWCNTs content produced a concurrent increase in the LOI of the composites which reached a maximum value of 31.30 ± 1.22% at 1 wt% MWCNT. The thermal stability was investigated using thermogravimetric analysis (TGA) and it was found that the addition of MWCNTs improved thermal stability, and increased the fire-retardance of the glass fabric reinforced epoxy (GF/EP) composites. The highest composite flexural strength (150 MPa) and flexural modulus (12 GPa) were attained at 0.5 wt% MWCNT. Above 0.5 wt%, a drop in strength and modulus was observed. The results from this study showed that the use of hybrid reinforcement containing MWCNTs can help to significantly improve the flame retardance, water absorption, and mechanical properties of reinforced composites by incorporating optimum amount of MWCNTs.

Comparative Investigations on Fracture Toughness and Damping Response of Fabric Reinforced Epoxy Composites

Studies were conducted to observe the effect of fracture toughness and damping response on fabric reinforced epoxy polymer composites. The samples of glass fabric, kevlar fabric and carbon fabric having 15wt%, 25wt%, 35wt%, 45wt% and 55wt % fabric content were prepared and tested following ASTM standards. Fracture toughness, peak load and increase in energy absorption are determined for the fabric-epoxy composites. Effect of temperature on storage modulus, loss modulus and tan delta values for various percentages of fabric epoxy composites are noticed and corresponding damping response behaviour is determined. The results revealed that reduction in strength at higher percentage of fabric content is due to improper bonding between fabric and epoxy resin. Higher peak load values and increased values of energy absorption are observed at lower percentage of fabric content. Kevlar fabric proves to be beneficial for specific energy absorption capability. Strength retention capability at higher temperature is far better for carbon fabric epoxy combinations. Composites with lower fabric content retain much higher temperature and peak load. Also the experimental findings are in close proximity with that of theoretical results.

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.

Structure and mechanical properties of windmill palm fabric reinforced composites

Applications of environmentally friendly high-performance materials derived from natural fibers have attracted tremendous attention. Windmill palm mesh is a novel fiber web with a natural 3D structure. In this paper, natural 3D windmill palm mesh and windmill palm/flax fabrics were prepared as reinforcing materials to prepare epoxy matrix composites. The effects of fiber content, chemical treatment, and textile structure on mechanical properties of the palm materials based composites were investigated. The results showed that the palm materials reinforced composites had excellent mechanical properties. The palm mesh/epoxy composite had a tensile strength of 78 ± 7 MPa, and a young's modulus of 991 ± 92 MPa, when the fiber concentration was 60%. The alkalized windmill palm fiber/flax twill fabric reinforced epoxy composite has a high fracture specific work of 343 KJ/m2.

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.

Experimental Analysis of Mechanical and Thermal Characteristics of Luffa/Epoxy Polymer Composite under the Influence of Nanosilica

In the current work, the experimentations have been accomplished to assess the impact of diffusing nanosilica particles in epoxy matrix on the mechanical and thermal performance of the luffa fibre reinforced epoxy composite material. The matrix and fibre composition are fixed as 80 : 20 throughout the study, and the nanosilica is disbanded in diversified volume fractions of 0%, 0.5%, 1.0%, 1.5%, 2.0%, and 2.5%, respectively, while preparing luffa/epoxy/nanosilica (LES) composite samples. The mechanical characteristics, such as tensile, flexural, and impact behaviour of the composite, and the thermal properties, namely, thermal stability and thermal conductivity, are examined for the LES samples. The experiments are accomplished as per the ASTM standards. The results revealed that the assimilation of nanosilica particles in epoxy has improved the mechanical and thermal characteristics of the composite significantly. The tensile, flexural, and impact strength of the composite have been amended by 157.58%, 66.9%, and 16.5% with 1.5% addition of nanosilica in epoxy. Similarly, thermal conductivity of the composite is improved by 47.53% with the dispersion of 2.5% nanosilica in epoxy matrix. In addition, the thermal stability of the LES composite samples is substantially improved while disbanding nanosilica in epoxy matrix. However, the better results are reported for the LES composites containing 1.5% nanosilica content, compared to the next higher volume fractions of nanosilica content in epoxy matrix.

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.

Wettability of a hybrid PTFE/Kevlar fabrics at micro-, meso-, and macroscales

Hybrid PTFE/Kevlar fabric reinforced epoxy composites have widely been used as structural self-lubricating liners. To achieve the best working performance, the Kevlar rich side has to be well impregnated (good wettability), whereas the PTFE rich side must remain dry at the same time. Consequently, it is essential to study the wetting properties of both sides from the microscale (fibre) to the macroscale (fabric) via the mesoscale (tow). After characterization of the wetting properties of hybrid PTFE/Kevlar fabrics at each scale, a revised Cassie-Baxter model was developed, linking the three scales and taking into account the three phases, i.e. air, PTFE and Kevlar. Water contact angles served to characterize the wetting properties at every scale and to validate the predictions. This study aims at providing a better insight into the hierarchical wetting of fibrous materials, both from experimental and theoretical perspectives.

Influence of Laying Angles in Reinforcement of Epoxy in Sisal Plain Woven Structures

This study is about microstructure characterization and understanding the flexural properties of plain-woven sisal fabric reinforced epoxy composites. Vibrational Spectroscopy (FTIR) and SEM (Scanning Electron Microscopy) were used to describe the plain-woven sisal fabric and sisal fiber reinforced epoxy composites. Two laying angles were incorporated into the epoxy resin (10 percent), i.e. [0°/90°] and [0°/45°]. To isolate the effect of epoxy type and whether woven sisal fibers were used, an analytical design that is based on [0°/90°] and [0°/45°] orientation used the results. Epoxy treated with woven sisal fibers had a higher tensile (0.62 GPa) and flexural modulus (0.69 GPa) with tensile (17 MPa) and flexural strength (14 MPa) while being applied to a surface that is sloped at 0°/45° and which generates a displacement force of approximately 12 mm and strain 15.8 %. While conventional Weibull failure theory has long been widely used to explain the failure of brittle bulk materials, this new equation integrates that theory with the lay angle effect on flexural strength in plain sisal to calculate flexural strength reinforcement in epoxy. This new method can be applied to any fiber reinforcement, regardless of the type, and in terms of the failure of that reinforcement, which is governed by linear elastic fracture mechanics, and agreement between experimental data sets is excellent. According to our expectations, this theoretical study is going to provide a new method for the advanced strain engineering system to be built using reinforced fibers.

Water Absorption Behavior and Its Effect on Static Mechanical and Dynamic Mechanical Properties of Flax Fabric Reinforced Epoxy Composites

ABSTRACT In this work, four different grades of the Alkali cum Silane-treated plain-derived (irregular type) basket woven Flax fabric reinforced Epoxy (ASFE) composites were fabricated by varying their fiber weight fractions (0, 25, 35, and 45 wt.%) using compression molding technique. ASFE samples were subjected to salt water immersion test for 18 days and studied its effect on the their static and dynamic mechanical properties in accordance with ASTM standards. Also, interfacial shear strength between single flax fiber and epoxy material was determined using micro-droplet bonding test. Experimental Investigations revealed that salt water absorbed (SWA) flax/epoxy composites showed maximum drop of 23.23%, 29%, 35.43%, and 18.53% in tensile, flexural, impact and interlaminar shear strength, respectively. DMA study revealed that glass transition temperatures (Tg) of the ASFE composites were sensitive to the moisture absorption, and hence, SWA composites exhibited lower Tg value than dry composites. Furthermore, scanning electron microscopy clearly exposed fiber splitting, micro-cracks, and poor interfacial bonding of the ASFE composites.

Effect of Pretreatment on the Mechanical Properties of Orange Peel Particulate (Bio-Waste)-Reinforced Epoxy Composites

Effects of chemical treatments with benzoyl chloride, acetone and alkali on the physical and mechanical properties of Orange Peel Particulate (OPP) reinforced epoxy composite materials have been studied. Hand lay-up technique was applied to manufacture the composites. The experimental results illustrate that chemical treatment with benzoyl chloride has a considerable impact. The properties of OPP reinforced composite material have been enhanced by 15% (for tensile test) and 30% (in case of flexural test) due to benzoyl chloride treatment as compared to raw OPP composites. It is evident from Fourier Transform Infrared Spectroscopy (FTIR) that non cellulosic content was removed from the surface of the fiber due to benzoyl chloride treatment. After chemical treatment there was good interfacial bonding between matrix and filler material as observed in SEM micrographs. From the experimental observations, it can be seen that among all fabricated composites, set of composites with 30% filler loading yields excellent mechanical properties.