Vacuum Bagging Technique Research Articles

Effect of Clay, Mixing Speed, and Time on Mechanical Properties of Glass Fiber/Clay Reinforced Unsaturated Polyester Prepared by Vacuum Bag Technique

Effect of Clay, Mixing Speed, and Time on Mechanical Properties of Glass Fiber/Clay Reinforced Unsaturated Polyester Prepared by Vacuum Bag Technique

Experimental, Theoretical, and Numerical Analysis of Laminated Composite Prosthetic Socket Reinforced with Flax and Cotton Fibers

A lot of work has been done to enhance the mechanical properties of natural fiber composites to increase their strength and applicability. This research aims to investigate the utilization of natural fibers for below-knee prosthesis socket manufacture using the vacuum bagging technique experimentally, theoretically, and numerically. Lamination groups of different layering arrangements were evaluated by tensile tests. The finite element methodology (FEM) was utilized by noting the dispersion of safety factors, equivalent Von-Mises stress, and total deformation, while the theoretical part estimated Poisson's ratio, volume fraction, failure index, and theoretical safety factor. The study found that the number and type of fibers affected mechanical properties, in addition, that combining natural and artificial reinforcements permits the creation of high-performance bio-composites. FEM results coincided with both the theoretical and experimental results, with lamination 9 having the highest modulus of elasticity (5.6 GPa) and tensile strength (423 MPa). This work uncovered the properties of the proposed hybrid fiber-reinforced composites that haven't been exasperated up to the present and showed that sockets can be assembled from sustainable, low-risk materials without sacrificing the composite materials' strength. The study found that bio-composites with better performance could be created by combining synthetic with natural reinforcements.

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.

Thermomechanical properties of imidazolium ionic liquid-modified mwcnt/carbon fiber/epoxy hybrid composite laminates

Hybrid composite laminates with nanofillers are high performance materials for thermal and structural applications. In this work, multiwall carbon nanotubes (MWCNT) were non-covalently modified by treating them with 1 wt% or 5 wt% of ionic liquid (IL), 1-butyl-3-methylimidazolium chloride. The treated MWCNT were dispersed in epoxy resin (weight content: 0.2–2 wt% or 1 to 3 wt%, respectively) and used to obtain hybrid composite laminates based on carbon fibers (CF) molded by hand layup and vacuum bagging techniques. The hybrid composite laminate containing 1 wt% of MWCNT modified with 1 wt% of IL showed the best mechanical and thermomechanical properties, including an increase of 210% and 151% in flexural strength and modulus, and an increase of 101%, 116% and 29.3% in storage modulus, loss modulus and damping, respectively. Scanning and transmission electron micrographs showed the enhanced MWCNT dispersion and network at low IL content, justifying its improved mechanical properties. The application of a low amount of IL dispersant was found a promising approach to prepare MWCNT/CF/epoxy composites with enhanced properties.

Laminated Jute and Glass FibreReinforced Composite forRepairing Concrete Through Wrapping Technique

Natural fiberreinforced composite in concrete structure material has attracted many researchers and engineers in recent decades due to its good agreement in mechanical properties, economics, and sustainability. An experimental investigation was conducted to investigate the jute and glass fiberlaminated composite for cylindricalconcrete repair.Jute and glass fiberwere used as reinforcement, and vinyl ester (VE) served as the matrix.The vacuum bagging technique was used to wrap the cylindrical concrete columns with a diameter of 50 mm and a height of 150 mm.Compression and Brazilian tests were performed on the specimen.It was discovered that the four (4) layers of jute fiberreinforced thermoset (JFRT) composite had the highest mechanical properties, with an improvement of 72.62%when compared to glass fibrereinforced thermoset (GFRT) composite. It can be concluded that both GFRT and JFRT had the potential to improve the mechanical properties performance of cylindrical concrete specimens with an increase of up to five (5) layers of woven fiber.The results presented here may facilitate improvements in the concrete specimen by using JFRT where it was suggested to have a higher improvement for the concrete specimen with the optimum layers applied.As a result, jute fiberhas been shown to perform better and can be used as an alternative to glass fiber.As a result, jute fiberhas been shown to perform better and can be used as an alternative to glass fiber.

Effect of nanoparticles in natural fiber reinforced polymer composites

Fiber surface modifications by chemical treatment and matrix modification with nanofillers are two key techniques used in recent times to improve the natural fiber reinforced polymer composite strength. The impact of titanium dioxide (TiO2), magnesium oxide (MgO), and zinc oxide (ZnO) nanoparticles on the mechanical properties of 6% sodium hydroxide alkali treated kenaf fiber reinforced epoxy composites has been experimentally examined and reported in this research article. All the composite samples were fabricated using vacuum bagging technique, with 35% Fiber weight ratio. The nanofillers were added in 3% weight proportion of total composite weight using ultrasonication method. According to ASTM standards, the prepared samples were evaluated for tensile, flexural, and impact strength. The experimental results showed that, 6% NaOH treatment on kenaf fibers showed 11.2%, 24.9%, 8.4%, and 28.7% improvement on tensile strength, modulus, flexural and impact strength respectively. The addition of different nano particles in the matrix phase performed well on effective stress transfer between fiber layers through matrix layers, hence improvement on mechanical properties were noted.

Determination of carbon nanotubes penetration level into epoxy-woven glass fibre composite laminates manufactured with vacuum infusion process via electrical conductivity measurement

ABSTRACT This study investigates the carbon nanotube (CNT) penetration phenomenon in vacuum infusion (VI) process by means of electrical conductivity measurement. Effects of resin temperature, CNT content, and the processing technique on the overall composite laminate quality were investigated by monitoring electrical properties of composite sheets. Epoxy/woven glass fibre composites loaded with various CNT contents were also manufactured using compression moulding and vacuum bagging techniques for comparison purposes. VI was achieved at two different temperatures (25°C and 50°C) to study the effect of variation in viscosity on CNT penetration during infusion. The results showed that electrical conductivity measurement was a very effective tool to assess the CNT penetration state of composite laminates in VI method. Both the resistive and capacitive behaviour in composite laminates due to filtration of CNTs at higher CNT contents was observed. However, the CNT penetration was improved by increasing the temperature of epoxy/CNT mixture before the infusion.

Flammability and vibrational study of graphene incorporated epoxy/ramie/glass hybrid nanocomposite

AbstractHybrid polymer composites are vastly used in aerospace, construction, and automotive fields. This study aims to analyze the flammability and vibrational behavior of graphene incorporated epoxy/ramie/glass (ERG) hybrid nanocomposite. The samples were prepared with different weight percentage of graphene (GR) through hand layup method, followed by vacuum bag technique. The samples were analyzed for water intake, porosity, mechanical strength, fractography, vibrational property together with flammability of the material. GR addition depletes water intake and porosity by 11.5% to 5.3% and 6.2% to 2.2%, respectively. It increases hardness and flexural strength up to 25% and 41%, with a reduction in tensile property of the composites. Besides, GR nanocomposites show improved damping properties, owing to stick‐slip mechanism exhibited at epoxy and GR interface. Also, GR addition declines burning rate of ERG at high concentrations since it does not score any grade in flammability test. This work found that the incorporation of GR in ERG composite enhances mechanical properties and decreases water intake. A decrease in the burning rate of the ERG composite could be achieved by incorporating graphene particles, which could be used for structural applications (car door‐panels, ballistic, and aerospace) leading to delay in burning rate of the developed composites when exposed to fire during accidents.

Investigation of tensile properties, hardness, and morphology of h-BN and MoS 2 filler modified carbon fabric/epoxy composites

The present study aims to improve the tensile and hardness properties of carbon fabric–reinforced epoxy composite (CFEC) by using hexagonal boron nitride (h-BN) and molybdenum disulfide (MoS2) fillers. Magnetic stirring and ultrasonication were used to disperse fillers in epoxy resin. CFEC, h-BN filled CFEC and MoS2 filled CFEC fabricated as per hand layup and vacuum bag technique. The tensile strength of CFEC was remarkably improved up to 6 wt.% h-BN and MoS2 addition separately in the resin matrix. The maximum tensile strength of 486 MPa and Young’s modulus of 44 GPa were noticed in 6 wt.% h-BN incorporated CFEC displaying 59% and 47% improvements, respectively. The maximum toughness is shown by 6 wt.% MoS2 incorporated CFEC indicating 102% improvement. The uniformly dispersed high-performance filler in the epoxy effectively transferred stress, improving tensile properties. However, filler agglomerates, stress-raising spots, and poor filler–matrix interaction beyond 6 wt.% filler reduced the tensile property improvement. The introduction of h-BN and MoS2 in the composite increased hardness, with 6 wt.% h-BN added CFEC recording the highest hardness denoting 23% greater than the neat CFEC.

Life cycle assessment of carbon fiber and bio-fiber composites prepared via vacuum bagging technique

Over the past few decades, increasing demand for light weight material have grown in various applications including aerospace, and other structural applications with added focus on green engineering and sustainability. Particularly in aerospace industries, utilisation of carbon fiber composites results in increased rate of pollution due to its inability to be repaired and recycled. Therefore, it is envisaged that migrating to biocomposites could be the solution forward depending on the manufacturing techniques. This life cycle assessment concentrates on understanding the emission rate of vacuum bagged carbon fiber and biocomposites with focus on its recycling abilities. In this study, carbon composites indicated a global warming potential (GWP) of 54 kgCO2Eq. whereas biocomposites showcased 12 kgCO2Eq. This implies that GWP of biocomposites were approximately four times less than carbon composites and if pesticides and fiber spinning are controlled, emission could be further reduced along with the overall energy consumption along with other emissions. Although biocomposites showcased lower environmental impact in mostly every scenario, the transition towards biocomposites still requires research to fulfil gaps with regards to the enhancement of mechanical properties compared to carbon fiber composites.

진공백법으로 제조된 아라미드/에폭시 복합체의 개발 및 물리적 특성 분석

The manufacturing process of composite materials is crucial in determining their final quality and mechanical and physical properties. Although manufacturing defects affecting mechanical properties cannot be entirely eliminated, some process parameters can be improved to reduce them, and solutions without increasing manufacturing costs are sought. Currently, research on aramid fibers and epoxy resin is booming; thus, this study aims to apply the vacuum bag process with epoxy matrix and aramid fiber reinforcement, focusing on the manufacturing process parameters. Herein, a procedure for the hand lay-up of aramid impregnated with resin and the vacuum bag method for a composite laminate is described. Some variations and improvements in the vacuum bag technique were applied, improving the breathable layers in the mold to enhance the extraction of gases and promote a homogenous pressure distribution. ASTM procedures were performed to obtain the density and constituent content of the composite material, resulting in a fiber volume fraction of 0.606, a resin volume fraction of 0.294, and a porosity volume fraction of 0.098.

Enhancement of mechanical properties of matrix by functionalized Multi-Wall Carbon Nanotubes (MWCNT) in composite material

In present era, Multi-Wall Carbon Nanotubes (MWCNTs) added composites are used to enhance the mechanical properties which are mostly used in aerospace and defense applications. This paper is about fabrication and testing of four different epoxy matrix laminates. Amine and Carboxylic Functionalized CNTs, un-Treated-Multiwall carbon nanotubes (MWCNTs) and Carbon fiber/epoxy, having variation of 0.5 wt% of multiwall carbon nanotubes (MWCNTs), which is fabricated by using vacuum bagging Technique with carbon fiber as reinforcement. The composites are tested for flexural and inter-linear shear strength (ILSS) and Tensile as per ASTM standards D790, D2344, and D3039. From the test results and analysis, it is found that Carboxylic Functionalized CNTs added epoxy resin has higher flexural and inter-laminar shear strength (ILSS) when compared with other CNTs and in terms of Tensile strength perspective Amine Functionalized CNTs showed better results.

Effect of ammonium polyphosphate on fire‐retardant, mechanical, and vibrational analysis of epoxy/glass/ramie hybrid composite

AbstractHybrid polymer composites (synthetic and/or natural fiber) are highly prominent in the fields of automotive, aerospace, construction, and marine. This work aims at developing a novel epoxy/glass/ramie (EGR) hybrid composite incorporated with ammonium polyphosphate (APP) using a vacuum bag technique, thus by changing the weight percentage of APP. The hybrid composites were characterized for the fire‐retardant (vertical and horizontal burning test), mechanical (hardness, tensile, and flexural testing), wettability, porosity (ethanol infiltration), and vibrational properties. The flammability data show that the hybrid composites made of 10, 15, and 20 weight percentages of APP obtained V‐1, V‐0, and V‐0 grades in the UL‐94 vertical burning test. Furthermore, there is an enhancement in hardness properties, but it reduces the tensile and flexural strength. However, the integration of APP reduces the water absorption rate of the composite from 11% to 5%. This study found that APP‐reinforced EGR hybrid composite improves fire resistance, thereby reducing the water absorption rate, which hikes the usage of the material for structural application.

The Impact of Laminations on the Mechanical Strength of Carbon-Fiber Composites for Prosthetic Foot Fabrication

Carbon-fiber composites are considered to be one of the suitable materials for the fabrication of prosthetic feet. However, commercially available composites-based prosthetic foot designs present several problems for lower limb amputees, such as low tensile strength, reduced impact resistance, high cost, and weight structure. Modulating the mechanical properties of carbon-fiber composites using a simplified method can help reduce these issues. Therefore, our present research aims to identify the impact of increasing the concentration of carbon fiber in the fabrication of carbon-fiber composites by using the hand layup method without the vacuum bagging technique. To improve the mechanical strength of carbon-fiber laminates, an increasing number of carbon-fiber layers are used in sample preparation. This study aims to determine the tensile strength of the laminates with a different number of carbon-fiber laminations. For the preparation of the sample specimen, black 100% 3 K 200 gsm carbon fiber with a cloth thickness of 0.2 mm and tensile strength of 4380 Mpa was laminated with two parts of epoxy resin Araldite® LY556 and Aradur hardener at a ratio of 100:30 to make the test specimen. The results indicated an overall improvement in the tensile strength of carbon-fiber laminates owing to the increase in the number of carbon-fiber layers in successive samples. The maximum achieved tensile strength through the present experimental protocol is 576.079 N/mm2, depicted by a prepared specimen of 10 layers of carbon fiber. Secondly, an increase in the deformation rate has also been observed by increasing the loading rate from 2 mm/min to 5 mm/min during the tensile testing of fabricated samples. These sample carbon-fiber composites can be used in the fabrication of prosthetic feet by controlling the experimental conditions. The fabricated prosthetic foot will assist in rehabilitating lower-limb amputees.

PVDF green nanofibers as potential carriers for improving self-healing and mechanical properties of carbon fiber/epoxy prepregs

Abstract The novel aligned polyvinylidene fluoride (PVDF) green core–shell nanofibers were reinforced to carbon fiber/epoxy prepregs and were manufactured through the vacuum bagging technique. Aligned nanofibers were achieved by suspending a grounded needle between the nozzle and the collector of electrospinning. The self-healing properties were tested through a periodic three-point bending test at an interval of 24 h at room temperature. The healing behavior was further confirmed through field-emission scanning electron microscopy coupled with dispersion X-ray spectroscopy (EDX) and an electrical conductivity test. The self-healing prepregs (1038.42 MPa) regained 66% of their original strength (1577.85 MPa) after the initial damage. EDX analysis confirmed the elements of the resin (VE (C, O)) and hardener (MEKP (C, O), CN (C, O, Co)) from the ruptured healing carriers. The damaged carbon prepregs healed by showing electrical conductivity of around 83%. The mechanical properties of self-healing composites were tested by tensile, flexural, and Izod impact tests and showed an increment in both flexural (7–12%) and impact strength (5–7%) with the addition of nanofibers. Overall, the research findings provided a design of eco-friendly carriers for carbon fiber-reinforced composites to obtain decent self-healing properties without deteriorating the mechanical strength.

Influence of nanoclay filler on mechanical properties of CFRP composites

Nanoclay is an innovative nanofiller with appealing qualities such as strong compatibility with a wide range of polymers and excellent mechanical, thermal, and electrical properties. This work reveals the fabrication of carbon fibre reinforced polymer (CFRP) composites by adding various wt % (0, 1.25, 2.50, 3.75) nanoclay in epoxy using the vacuum bagging technique. Mechanical properties such as flexural strength, interlaminar shear strength (ILSS), and tensile strength tests were performed on neat CFRP and nanoclay embedded CFRP composite to determine the effect of adding nanoclay on the mechanical properties of CFRP. The result obtained from these tests concludes an increase in flexural, ILSS, and tensile strength continuously up to 2.5 wt% of nanoclay after further addition of nanoclay, these properties decrease.

Tensile and Stress Analysis of Hybrid Composite Prosthetic Socket Reinforced with Natural Fibers

Natural fibers and their composites are the evolving movements in material science, and with that, the utmost use of plant-based fibers has become the focus of this research. Sisal and cotton natural fibers were used to construct a prosthetic socket as an attempt to substitute material currently available in the manufacturing of sockets. The vacuum bagging technique was adopted to produce a below-knee socket. The influence of different fiber layering sequences on the volumetric and mechanical characteristics was estimated experimentally and numerically. Mechanical tensile tests were used to assess laminated specimens, such as tensile strength, young modulus, and elongation percentage. The number and type of reinforcing layers had an effect on mechanical properties, and the best composite specimens were three layers of sisal with two layers of carbon fiber, with tensile strength and modulus of elasticity reaching (261–4760) MPa, respectively. The finite element method (ANSYS- 16.1) was used to anatomize by seeing the contours distribution of safety factor, equivalent Von Mises stress, equivalent Von Mises strain, and total deformation. This procedure was executed by building ten models for the socket, which served as three-dimensional structural composite materials. The results of the present study advocate that the arrangement of natural and synthetic reinforcements allow the preparation of bio-composites with enhanced performance. This work revealed the assets of sisal and cotton fiber hybrid reinforced PMMA resin composites (hybridized at diverse volume percentages and lamination layup), which have not been tried up to now.

Biodegradation behaviour of green composite sandwich made of flax and agglomerated cork

Material experts are striving to use natural resources as skin and core in composite sandwiches to achieve light weight, biodegradability, and cost benefits. This paper reports one such newly developed green composite sandwich and its biodegradable behavior. The skin and core of newly developed sandwich are flax fiber and agglomerated cork respectively. This composite sandwich is manufactured by vacuum bagging technique in order to get higher volume fraction of fiber. The biodegradability testing of the composite sandwich has been executed by soil burial test. The verification of the same has been done using Scanning Electron Microscope (SEM) images, Fourier Transform Infrared Spectroscopy (FTIR) analysis and Thermoanalytical test. The test results portray the percentage of weight loss in the specimens and that, it increases with burial time. It also depicts that the newly developed Green Composite Sandwich (GCS) has 82% higher degradation than the Synthetic Composite Sandwich (SCS) taken for the comparison. SEM images show that the green composite sandwiches have lost their fibrous structure and cell wall surface due to the degradation. FTIR and Thermoanalytical tests also confirm the biodegradability of the developed green composite sandwich.

Rapid synthesis of ZnO nanostructures on woven carbon fiber using microwave treated chemical bath deposition and their characterization

Microwave-assisted chemical bath deposition (MACBD) is a new method for synthesizing metal-oxide layers and nanostructures efficiently. The fast synthesis of ZnO nanostructures (NSs) on woven carbon fiber (WCF) is reported in this study employing the MACBD technique. An aqueous solution of tetra ammonium zinc complex was used to create several morphologies of ZnO NSs on WCF fabric, including nanopetals, twinned nanospheres, nanoflowers, and nanoflakes. Under microwave heating, plain WCF fabric samples were treated with several precursor solutions. When compared to conventional CBD, the development time of ZnO NSs is lowered to roughly 2–4 min. Field-emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), and an X-ray diffractometer were used to evaluate as-developed ZnO NSs morphologies on WCF. The processing of ZnO NSs on the strands of carbon fibers was interpreted using FESEM, and it was discovered that variations in microwave duration and precursor solution are the primary causes of ZnO morphology development. With the formation of nanostructures, the crystalline peak height of the nanostructures increases. For the fabrication of high performance ZnO nanostructured WCF hybrid polymer composites vacuum bagging technique were used along with resin transfer system. Epoxy resin was applied as a matrix material with the five layers of ZnO grown WCF for varied applications.

Vibrational analysis of glass/ramie fiber reinforced hybrid polymer composite

AbstractNatural fiber reinforced hybrid polymer composites have gained extensive applications in recent decades owing to their damping, low density, biodegradability, and low‐cost benefits. This research explores the impact of the surface treatment, and the number of ramie fiber layers on the vibrational and mechanical characteristics of a glass/ramie fiber reinforced hybrid polymer composite. The composite is made of outer layer (glass fiber) and inner layer (ramie fiber) at different concentrations (varying between 2, 3, and 4). The ramie was pre‐treated with sodium hydroxide (NaOH) at different weight percentages (1%, 2%, and 5%). The composites have been fabricated using the vacuum bag technique. The composites have been characterized for chemical, mechanical, morphological, and free vibrational analysis. Fourier transform infrared spectroscopy and scanning electron microscope have been used to study the chemical characteristics and morphological study of the composites respectively. The mechanical properties of the composite were evaluated through tensile and flexural testing. The hybrid composite reinforced with two layers of ramie fiber as the core with 2% pre‐treated shows the maximum tensile strength of 120 MPa and flexural modulus of 12,147 MPa. Overall, the hybridization and NaOH pre‐treatment to certain ratio helps in increase in the hybrid composite's mechanical strength compared to the natural fiber composite.