Application Of Fiber Reinforced Composites Research Articles

3D Textiles Based on Warp Knitted Fabrics: A Review.

Fibre-reinforced composites (FRCs) are already well established in several industrial sectors such as aerospace, automotive, plant engineering, shipbuilding and construction. The technical advantages of FRCs over metallic materials are well researched and proven. The key factors for an even wider industrial application of FRCs are the maximisation of resource and cost efficiency in the production and processing of the textile reinforcement materials. Due to its technology, warp knitting is the most productive and therefore cost-effective textile manufacturing process. In order to produce resource-efficient textile structures with these technologies, a high degree of prefabrication is required. This reduces costs by reducing the number of ply stacks, and by reducing the number of extra operations through final path and geometric yarn orientation of the preforms. It also reduces waste in post-processing. Furthermore, a high degree of prefabrication through functionalisation offers the potential to extend the application range of textile structures as purely mechanical reinforcements by integrating additional functions. So far, there is a gap in terms of an overview of the current state-of-the-art of relevant textile processes and products, which this work aims to fill. The focus of this work is therefore to provide an overview of warp knitted 3D structures.

A virtual scale approach to multi-scale calculations and its application in fiber-reinforced composites

With the development of materials science and technology into the nano-/micro-world, multi-scale problems have become a research focus. Multi-scale calculations usually select a periodic structure as a representative unit with a certain physical meaning and can represent the material properties at a given scale. However, due to the large number of representative elements with complex shape and boundary conditions, the workload of multi-scale calculations is normally huge. In the present effort, a novel virtual scale method is proposed for multi-scale calculations. To demonstrate the validity and significance of the new algorithm, multi-scale calculations have been carried out for the prediction of properties of the ever-popular fiber reinforced composite materials. The equivalent elastic modulus, Poisson's ratio and coefficient of thermal expansion (CTEs) of fiber reinforced plastic in different scales predicted by the new method have been compared with those predicted by the well-established finite element method (FEM) and checked against the experimental results. The good agreements offer solid proof in terms of the validity of the newly developed virtual scale method. In principle, the method can be extended to tackle all multi-scale problems.

Star-shaped arylacetylene resins derived from silicon

Abstract Star-shaped arylacetylene resins, tris(3-ethynyl-phenylethynyl)methylsilane, tris(3-ethynyl-phenylethynyl) phenylsilane, and tris (3-ethynyl-phenylethynyl) silane (TEPHS), were synthesized through Grignard reaction between 1,3-diethynylbenzene and three types of trichlorinated silanes. The chemical structures and properties of the resins were characterized by means of nuclear magnetic resonance, fourier-transform infrared spectroscopy, Haake torque rheomoter, differential scanning calorimetry, dynamic mechanical analysis, mechanical test, and thermogravimetric analysis. The results show that the melt viscosity at 120 °C is lower than 150 mPa⋅s, and the processing windows are as wide as 60 °C for the resins. The resins cure at the temperature as low as 150 °C. The good processabilities make the resins to be suitable for resin transfer molding. The cured resins exhibit high flexural modulus and excellent heat-resistance. The flexural modulus of the cured TEPHS at room temperature arrives at as high as 10.9 GPa. Its temperature of 5% weight loss (T d5) is up to 697 °C in nitrogen. The resins show the potential for application in fiber-reinforced composites as high-performance resin in the field of aviation and aerospace.

Fiber-reinforced composites in endodontic practice: a review

Fiber-reinforced composites (FRCs) are a group of non-metallic biomaterials characterized by good mechanical properties, such as high fatigue resistance and fracture toughness growing in popularity in several dental applications. FRCs are a combination of two materials: the reinforcing phase in the form of fibers, which are embedded into the other material, called the matrix phase. Factors influencing the properties of FRCs include fibre properties versus polymer matrix properties, impregnation of fibres in the resin, adhesion of fibres to the polymer matrix, quantity and direction of fibres, and location of the fibre-rich phase in construction. The most commonly used applications of FRCs are in removable dentures, minimally invasive fixed dental prostheses, periodontal splints, root canal posts, and orthodontic retainers. This article discusses in detail the applications of FRCs in endodontics, including root canal posts, reinforcement of restorative composites in restorations and core build-ups and splinting of teeth in dental trauma.

Travel beyond Clinical Uses of Fiber Reinforced Composites (FRCs) in Dentistry: A Review of Past Employments, Present Applications, and Future Perspectives.

The reinforcement of resins with short or long fibers has multiple applications in various engineering and biomedical fields. The use of fiber reinforced composites (FRCs) in dentistry has been described in the literature from more than 40 years. In vitro studies evaluated mechanical properties such as flexural strength, fatigue resistance, fracture strength, layer thickness, bacterial adhesion, bonding characteristics with long fibers, woven fibers, and FRC posts. Also, multiple clinical applications such as replacement of missing teeth by resin-bonded adhesive fixed dental prostheses of various kinds, reinforcement elements of dentures or pontics, and direct construction of posts and cores have been investigated. In orthodontics, FRCs have been used also for active and passive orthodontic applications, such as anchorage units, en-masse movement units, and postorthodontic tooth retention. FRCs have been extensively tested in the literature, but today the advances in new technologies involving the introduction of nanofillers or new fibers along with understanding the design principles of FRC devices open new fields of research for these materials both in vitro and in vivo. The present review describes past and present applications of FRCs and introduces some future perspectives on the use of these materials.

Crack Analysis of Fixed Support Fibre Glass Composite Beam Based on Natural Frequencies

A Fibre reinforced composites (FRCs) is a composite material made by plastic matrix and reinforced with thin fibres having high tensile strength and high flexural modulus. It is also known as fibre reinforced polymer (FRP) or glass reinforced plastic (GRP). The typical applications of FRCs include marine, aircraft, automotive industries, medical applications, building constructions, sports equipment and many industrial products. In this study specifically E-Glass epoxy resin composite beam is selected because of its high strength, high rigidity, less failure possibility, low cost and easy availability. This study aims to describe the presence of crack in fibre glass composite beam. The crack analysis is to be performed in order to analyze the crack before the failure, which influences characteristics like modes of vibration and natural frequencies. A numerical study is conducted to investigate the free vibration response using finite element method. To understand the phenomenon of crack generation and its approximate location, FFT analysis is to be done along with its validation on FEA.

A Hydrothermal Factor Calculating Approach Based on FEM for Fiber-Reinforced Composites

The wide range of applications of fiber-reinforced composites in numbers of engineering fields is demanding better understanding on its hydrothermal properties. Especially for those are applied under complex hydrothermal environment such as aircraft industry. However, most methods we used at the present are either complicated or demand high-cost. In this paper, a novel approach based on finite element method (FEM) is proposed to calculate the hydrothermal factor by supposing an original decrease in the laminates stiffness. The integrated strains, consisting of Room Temperature Dry (RTD) strain and FEM simulated strain with the Elevated Temperature Wet (ETW) strain, are used to make an estimate for the hydrothermal factor. Hence, this FEM approach with low cost can be used to calculate the hydrothermal factor without doing full-scale structural ETW experiments. Compared with experimental results of the notched compression and single-bolted joints, it can be concluded that the approach introduced in the present paper can predict excellently the determination scope of the hydrothermal factor reasonably even in structural scale.

Composites of sisal fiber/polypropylene based on novel vane extruder: Effect of interface and damage on mechanical properties

Sisal fibers were pretreated by alkali and maleic anhydride, and then mixed with polypropylene to fabricate sisal fiber-reinforced composites by a self-made vane extruder based on elongational flow field. Maleic anhydride-grafted polypropylene was used as compatilizer to increase the fiber/matrix interactions. The influence of treatment on the fibers structure, the damage to fibers in processing, interfaces of composites and the mechanical properties of composites were investigated. It was observed that the surface of treated fibers was improved obviously compared with that of untreated fibers, which was believed to increase the adhesion between the fibers and matrix. However, the treated fibers were more likely to be damaged during processing. In comparison to unmodified system, the incorporation of treated fibers could significantly enhance the mechanical properties of composites, especially adding the compatilizer of maleic anhydride-grafted polypropylene. The flexural and impact strengths were maximum for the sisal fiber/polypropylene and maleic anhydride-grafted polypropylene composites, and its tensile strength was also improved significantly. The major contribution of this change should be that the morphology of fibers could be well preserved in elongational flow field, which based on the vane extruder showed a good application in fiber-reinforced composites.

Innovative Material Systems for Composite Vehicle Structures

Prepreg-based materials currently used in high-end applications as well as SMC/BMC-based materials used in automotive body panels are not likely to lead the future growth in the application of fibre-reinforced composites in primary as well as secondary vehicle structures. Out-of-autoclave techniques based on rapid fibre preforming and part consolidation will drive the structural composites applications in aerospace and automotive sectors. Fibre preforming has been identified as a key bottleneck in the composites supply chain, considering recent growth predictions in civil airframe and automotive markets. Automated Tape Laying machines have modest deposition rates, and global autoclave capacity is not likely to cope with projected growth rates in composites. This paper investigates the potential for near-net preforming using conventional textile technology as well as robotic approaches. Robotic or multi-axial machines have been shown to extend the preforming capability of weaving, braiding and stitching concepts. A multi-axial weaving machine, equipped with automated trimming of non-interlaced tows, can create 3D woven preforms tapered in width as well as length directions. 3D preforms with through-thickness reinforcement have been created with a robotic system equipped with dry fibre lay-up and tufting capability. A 9-axis complex winding machine in conjunction with braiding has been demonstrated for preforming over complex mandrels.

E-Glass Fiber Reinforced Composites in Dental Applications

Fiber reinforced composites (FRCs) are more and more widely applied in dentistry to substitute for metallic restorations: periodontal splints, fixed partial dentures, endodontic posts, orthodontic appliances, and some other indirect restorations. In general in FRCs, the fiber reinforcement provides the composite structure with better biomechanical performance due to their superior properties in tension and flexure. Nowadays, the E-glass fiber is most frequently used because of its chemical resistance and relatively low cost. Growing interest is being paid to enhance its clinical performance. Moreover, various techniques are utilized to reinforce the adhesion between the fiber and the matrix. Oral conditions set special requirements and challenges for the clinical applications of FRCs. The biomechanical properties of dental materials are of high importance in dentistry, and given this, there is on-going scientific interest to develop E-glass fiber reinforced composite systems. FRCs are generally biocompatible and their toxicity is not a concern.

Surface Characterization of Differently Pretreated Flax Fibers and Their Application in Fiber-Reinforced Composites

Strong natural bast fibers, especially flax fibers, can be used to replace glass fibers in reinforced composites. The properties of natural fibers depend largely on maturity, retting and processing. Two chemical treatments were applied to retted and semiretted flax fibers to create better fiber to resin bonding and to show the effect of retting degree and successive purification processes on the mechanical properties of natural composite materials. Retted and semiretted flax fibers have been scoured and bleached with the objective of removing surface impurities and developing finer structure. To investigate the effect of adhesion promoter on the mechanical properties of natural fiber composite, a composite sample was prepared from bleached retted flax pretreated with adhesion promoter Isostearoyltitanate (ISTT). After treatments the fibers got cleaner and the measurements showed that the fiber fineness as well as the surface free energy increased. The treatments were accompanied by decrease in the fiber tenacity but it has been found not to be reflected to the final mechanical properties of the composite. No improvement was remarked by using Isostearoyltitanate for surface modification.

In vitro evaluation of push-out bond strength of direct ceramic inlays to tooth surface with fiber-reinforced composite at the interface

Failure of a restoration, where a part of a ceramic inlay and/or a cusp is fractured, is a common clinical problem. The application of fiber-reinforced composites at the tooth-inlay interface may prevent undesirable fractures in dental restorations. There is little information regarding the effect of a fiber- reinforced composite layer on the push-out bond strength of ceramic inlays to tooth structure. The purpose of this study was to compare push-out bond strengths of ceramic inlays to tooth structure using a layer of fiber weave-reinforced composite at the tooth interface with different adhesive systems. Forty standardized occlusal, conically-shaped cavities, 5 mm in occlusal diameter, 3.5 mm in cervical diameter and 3.5 mm deep, were prepared in extracted human molars using a truncated cone-shaped diamond rotary cutting instrument, the dimensions of which corresponded with those of prefabricated ceramic inlays. The teeth were divided into 2 groups according to the adhesive system used. Solobond Plus was used as a total-etching system and Futurabond NR as a self-etching system. Preetched and silanized ceramic inlays were bonded to tooth structure with or without a layer of bidirectional fiber weave (StickTech). The groups without fiber-reinforced composite layer served as controls. The inlays were cemented with dual-polymerizing luting composite (Bifix QM) and light polymerized for 40 seconds from the buccal, lingual, and occlusal surfaces. Specimens were thermal cycled (6000 x 5 degrees -55 degrees C) and 3.5-mm-thick discs were prepared for the push-out test. The discs (n=10) were tested in a universal testing machine and pushed out with a cross-head speed of 1.0 mm/min. The data were analyzed with analysis of variance (ANOVA) (alpha=.05). Failure modes were analyzed using a stereomicroscope and SEM. Push-out mean bond strength (SD) values in MPa of direct ceramic inlays were: Solobond Plus (control): 9.7 (3.9), Solobond Plus with fiber-reinforced composite: 10.5 (5.0), Futurabond NR (control): 8.4 (2.5), Futurabond NR with fiber-reinforced composite: 8.6 (2.2). The differences between groups were not significant for either adhesive system or with the use of fiber-reinforced composite layer at the interface. Mixed failures were observed in the control groups, whereas in the fiber-reinforced composite layer groups, failures were mostly cohesive within the fiber layer. No cohesive fracture of the tooth was observed when a layer of fiber weave was placed at the interface. Within the limitations of this in vitro study, a fiber-reinforced composite layer at the bonding interface of ceramic inlay did not influence the push-out bond strength. Futurabond NR self-etching system and Solobond Plus total-etching system demonstrated similar push-out bond strengths.

Acoustic Emission Monitoring and Analysis of Glass Fiber-Reinforced Composites Bridge Decks

The application of fiber-reinforced composites (FRP) is gaining momentum as an alternative material for bridge replacement, repair, and rehabilitation. While a number of states now use FRP, a lack of standards, codes, and performance data for FRP bridge decks has resulted in the use of FRP technology not being widely accepted. This paper presents the performance results, based on acoustic emission (AE), of six full-scale glass FRP bridge deck panels with nominal cross-sectional depths varying from 152 mm (6 in.) to 800 mm (30 in.). The objective was to develop for use during in-service field inspections an AE monitoring strategy that will determine the structural performance of the deck. As such, the characterization of damage, e.g., fiber breakage, matrix cracking, and delamination, was part of the investigated criteria and the contributing factors for identification of a monitoring strategy. Although some factors were determined to be associated with the performance evaluation of the structural integrity of the decks, further investigation is needed.

Polymer-matrix Composites for High-temperature Applications

Over the last decade, applications of fibre-reinforced composites using polymer matrices have seen tremendous growth. In spite of the complexity of their behaviour and the unconventional nature of fabrication and other aspects, the usage of such composites, even for primary loadbearing structures in military fighters and transport aircraft, and satellites and space vehicles has been beneficially realised. Most of such usage constituted structural applications (such as in airframe) where service temperatures are not expected to he beyond 120 'C. Attention is now focussed on expanding the usage of such composites to other areas where temperatures could be higher-in the range 200400 C. The intended applications are structural and non-structural parts on or around the aero-engines and airframe components for supersonic or hypersonic aircraft. The development of polymer matrices-such as bismaleimides, polyimides, cyanates, and liquid crystalline polymers and others-has brought such applications within the realm of practicability. The associated problems have been in terms of suitable processing technologies and in balancing the requirements of the performance with those of the processing. This paper describes briefly such developments and reviews the potential application scenario.

Design considerations for rotating laminated metal-matrix-composite shafts

A logical step in the application of fiber-reinforced composites is to take advantage of their light-weight/high-strength potential and replace traditional monolithic shaft designs with composite materials. In the case of aircraft engine shafts where the high-temperature environment excludes the use of most traditional materials, a high-strength titanium alloy is recommended. The focus of this paper is the evaluation of Ti-21S monolithic and SiC/Ti-21S composite shafts under various loadings and damage conditions. This is accomplished through the development of a fully inelastic axisymmetric generalized plane-strain model that incorporates the generalized method of cells (GMC) micromechanics model (that includes the capability of fiber/matrix debond), as well as the effects from a rotational body force. The inelastic analysis is performed through the method of successive elastic solutions. In this study, the elastic response of homogeneous and variously oriented fiber-reinforced shafts are compared in order to demonstrate the possible advantages of composite design. The greatest differences are observed in the circumferential stress and strain in the circumferentially wound (90°) shaft, with savings of as much as 11% in circumferential stress and 53% in circumferential strain compared to that of a similarly loaded homogeneous shaft. For the composite shafts subject to both inelastic effects and debond, the 90° strong and weak bond shafts offer the only consistent improvement over traditional monolithic designs. The interaction between any other fiber orientation and inelasticity/debond damage requires careful consideration of individual designs to create a reliable shaft. This paper demonstrates the feasibility of using lighter-weight/stronger composite shafts, as well as the complexity of the design problem, along with the careful consideration of practicality that must be taken prior to the abandonment of traditional monolithic designs in highly critical applications.