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Polymer composites have various application in automotive industry. Achieving vehicle efficiency in public transportation, among other goals, is often done by lightweight materials like fibre reinforced plastics as structural elements of the vehicle. A concept solution for a V shaped structural floor element of a city bus is proposed in this paper. CAD model of floor structural element has been designed from which, in later phases, construction of complete composite floor will be optimized and designed. Test sample made of hybrid (carbon and glass) fibre composite was produced and tested under the flexural load for comparison with a FEA model. Test sample displacement was measured using a GOM Tritop optical measurement system. Comparison showed that difference between real measurement and FEA for maximal displacement is only 11.7%.

The focus of this research work is to study the effect of hybrid fillers of bamboo fiber and commercial glass fiber on high density polyethylene (HDPE) matrix without interfacial coupling agent. The hybrid composite was formed through melt blending method using two-roll mixing mill at temperature of 160 oC and was shaped using compression molding machine. The highest value of Tensile Modulus at break and Hardness were obtained at hybrid ratio of 70 % of HDPE/ 15 % bamboo/ 15 % glass particles (H/B15/G15). However, the inclusion of the hybrid fillers did not show any significant difference in Impact strength from the molded blank HDPE samples (H/B0/G0) while the percentage water absorbed by the samples predominantly decreased as the content of the commercial glass filler was increase in the HDPE matrix.

The increased industrial use of fibre reinforced composites structures such as sandwich panels is a result of their lightweight, flexible, and high strength capabilities. Sandwich panels are generally assembled by placing a lightweight core in between two facesheets. The core provides the required thickness without increase in weight while the facesheets provide the required strength at less than half the cores thickness. Whilst the material choice for both vary, carbon and glass fibre reinforced polymers are predominantly the two main composite materials commonly utilised in the fabrication of sandwich panel facesheets. New developments in the application of fibre reinforced structures have raised an environmental and economic awareness for the necessity to recycle and repurpose fibre cut-off waste. The UK is the first major economy to pioneer a “green industrial revolution” by passing legislative laws, backed with funding, to bring industries such as the composite industry up to speed to achieve product sustainability and recyclability. With focus in the composite industry shifting towards zero waste production cycles, it becomes a necessity to investigate the mechanical behaviour of fibre cut-off waste in structures such as sandwich panels. This thesis aims to contribute towards the issue by presenting an experimental comparison of sandwich panels fabricated using recycled carbon fibre (RCF) and chopped strand matt glass (CSMG). The experimental work undertaken are three-point bending and low-velocity impact. Across all industry that utilise sandwich panels, the two phenomena mentioned are observed to contribute significantly to panel degradation during its working life. For fair comparison, the sandwich panels for both fibres consist of the same areal density and same manufacturing methods. Novelty in the thesis is granted through the comparative study between the mechanical behaviour of RCF and CSMG sandwich panels as this has not been investigated for industrial application. Obtained experimental data show that the RCF panels are stronger than the CSMG panels which could be an alternative to sandwich panels made with CSMG.

In this paper, glass fiber fabric reinforced polyphenylene sulfide composites were prepared by hot pressing. The effects of glass fibre modification and hot pressing temperature on the properties of the composites were investigated using a scanning electron microscope, infrared spectrometer, universal testing machine, and DIGEYE digital imaging colour measurement system. The results show that after the treatment with a silane coupling agent, the silane coupling agent was more uniformly distributed on the surface of the glass fibres, and the bonding effect between the glass fibre fabric and polyphenylene sulphide was significantly improved. The strength of the composites increased and then decreased with the increase of hot pressing temperature, and the surface colour of the composites became darker and darker. When the hot-pressing temperature is 310 °C, the mechanical properties of glass fabric-reinforced polyphenylene sulfide composites are at their best, the tensile strength reaches 51.9 MPa, and the bending strength reaches 78 MPa.

This study analysed the bonding mechanisms and strength between wood and non-wood implants in producing laminated oak-wood beams. The suitability of different types of adhesives, namely for load-bearing and general purpose, was also analysed. Three different types of non-wood implants—carbon fibres, glass fibres, and aluminium were glued with epoxy resin (ER), thermoplastic 1-k polyurethane adhesives (PUR), structural polyurethane adhesives (PUR 2 and PUR 3), and polyvinyl acetate (PVAc) adhesives and bonds were tested for shear strength (SS) according to ISO 6238:2018. Results of the bond quality expressed as the ultimate load to failure and displacement were recorded using the universal mechanical testing machine in combination with the digital image correlation (DIC) method. Before the shear test, all the samples were conditioned in dry and wet climatic conditions. Test results indicated that the application of PUR adhesives for bonding carbon and glass fibres with oak wood could sufficiently replace two-component ER, which is generally recommended for such purposes but is very challenging to utilise in industrial conditions. PVAc adhesives proved efficient only for combination with AL implants and in dry conditions. Aluminium sheets were shown to require surface pre-treatment, such as sanding and degreasing or a different type of adhesive to achieve sufficient adhesion.

As part of a large human biomonitoring study, we conducted occupational monitoring in a glass fibre factory inSlovakia. Shopfloor workers (n = 80), with a matched group of administrators in the same factory (n = 36), weremonitored for exposure to glass fibres and to polycyclic aromatic hydrocarbons (PAHs). The impact of occupationalexposure on chromosomal aberrations, DNA damage and DNA repair, immunomodulatory markers, andthe role of nutritional and lifestyle factors, as well as the effect of polymorphisms in metabolic and DNA repairgenes on genetic stability, were investigated. The (enzyme-modified) comet assay was employed to measure DNA strand breaks (SBs) and apurinic sites,oxidised and alkylated bases. Antioxidant status was estimated by resistance to H2O2-induced DNA damage. Baseexcision repair capacity was measured with an in vitro assay (based on the comet assay). Exposure of workers to fibres was low, but still was associated with higher levels of SBs, and SBs plus oxidisedbases, and higher sensitivity to H2O2. Multivariate analysis showed that exposure increased the risk of high levelsof SBs by 20%. DNA damage was influenced by antioxidant enzymes catalase and glutathione S-transferase(measured in blood). DNA repair capacity was inversely correlated with DNA damage and positively withantioxidant status. An inverse correlation was found between DNA base oxidation and the percentage ofeosinophils (involved in the inflammatory response) in peripheral blood of both exposed and reference groups.Genotypes of XRCC1 variants rs3213245 and rs25487 significantly decreased the risk of high levels of baseoxidation, to 0.50 (p = 0.001) and 0.59 (p = 0.001), respectively. Increases in DNA damage owing to glass fibre exposure were significant but modest, and no increases wereseen in chromosome aberrations or micronuclei. However, it is of concern that even low levels of exposure tothese fibres can cause significant genetic damage.

Natural fibre-reinforced composites have attracted a great deal of attention by the automotive industry mainly due to their sustainable characteristics and low cost. The use of sustainable composites is expected to continuously increase in this area as the cost and weight of vehicles could be partially reduced by replacing glass fibre composites and aluminium with natural fibre composites. Adhesive bonding is the preferred joining method for composites and is increasingly used in the automotive industry. However, the literature on natural fibre reinforced polymer composite adhesive joints is scarce and needs further investigation. The main objective of this study was to investigate experimentally adhesively bonded joints made of natural, synthetic and interlaminar hybrid fibre-reinforced polymer composites. The effect of the number of the interlaminar synthetic layers required in order to match the bonded joint efficiency of a fully synthetic GFRP bonded joint was studied. It was found that the failure load of the hybrid jute/glass adherend joints increased by increasing the number of external synthetic layers (i.e. the failure load of hybrid 3-layer joint increased by 28.6% compared to hybrid 2-layer joint) and reached the pure synthetic adherends joints efficiency due to the optimum compromise between the adherend material property (i.e. stiffness and strength) and a diminished bondline peel stress state.

This paper presents the results of an experimental investigation of the behaviour and strength of hybrid kenaf/glass fibre-reinforced epoxy tubes subjected to axial intermediate-velocity impact loading. The specimens under axial intermediate-velocity impact involve three filament winding orientation parameters of ±30°, ±45° and ±70° of hybrid kenaf/glass fibre-reinforced epoxy and glass fibre reinforced-epoxy. All materials and sampling were prepared at SIRIM STV Malaysia laboratory by using automated filament winding machine to obtain a proper intraply hybrid kenaf/glass composite tube fabricating procedure. Results from the study showed that the concept in fabricating intraply hybrid filament winding technique of natural/synthetic materials has performed similar physical crashworthiness of synthetic composite tube with various progressive crushing behaviours. It was also observed that the winding orientation parameter at θ = 30°, 45° and 70° of the hybrid composite tube have increased the energy absorber properties with 33%, 34% and 56% respectively, compared to the GFRP.

Manufacturing-based carbon fibre-reinforced polymer (CFRP) and glass fibre-reinforced polymer (GFRP) wastes (pre-consumer waste) were recycled to recover valuable carbon fibres (CFs) and glass fibres (GFs), utilising a novel thermal recycling process with a cone calorimeter setup. The ideal conditions to recycle both the fibres occurred at 550 &deg, C in atmospheric pressure. The processing time in the batch reactor to recycle CFs was 20&ndash, 25 min, and to recycle GFs it was 25&ndash, 30 min. The recovery rate of the recycled CFs was 95&ndash, 98 wt%, and for GFs it was 80&ndash, 82 wt%. Both the recycled fibres possessed a 100&ndash, 110 mm average length. The resin phase elimination was verified by employing scanning electron microscopy (SEM). Furthermore, the fibres were manually realigned, compression moulded at room temperature, and cured for 24 h by a laminating epoxy resin system. The newly manufactured CFRP and GFRP composites were continuous (uniform length from end to end), unidirectionally oriented (0&deg, ), and non-woven. The composites were produced in two fibre volumes: 40 wt% and 60 wt%. The addition of &asymp, 20 wt% recycled CFs increased the tensile strength (TS) by 12%, young modulus (YM) by 34.27% and impact strength (IS) by 7.26%. The addition of &asymp, 20 wt% recycled GFs increased the TS by 75.14%, YM by 12.23% and the IS by 116.16%. The closed-loop recycling approach demonstrated in this study can effectively recycle both CFRP and GFRP manufacturing wastes. Preserving the structural integrity of the recycled fibres could be an advantage, enabling recycling for a specified number of times.

Most widely recognized material in the present world is Concrete due its durability, and strength aspects. Hence by using different additives like Glass fibre and woven biaxial Geogrid the compressive strength test is carried out for M30 and M40 grade of concrete to improve the performance of concrete. The main aim of the present study is to analyze the compressive strength of concrete, when concrete is mixed with glass fiber and Geogrid, to meet the demands of the modern construction. The addition of Glass fibre into concrete increases the compressive strength of concrete than Geogrid concrete. Tests are conducted by using glass fibre and Geogrid. For 1 m3 of concrete 612grams of glass fibre for M30 grade of concrete and for M40 grade of concrete 697 grams of glass fibre for 1m3 of concrete are used. Geogrids are placed at 2 layers (50mm interval each) in a 150*150mm cube in both M30 and M40 grade of concrete.

The growing use of carbon and glass fibres has increased awareness about their waste disposal methods. Tonnes of composite waste containing valuable carbon fibres and glass fibres have been cumulating every year from various applications. These composite wastes must be cost-effectively recycled without causing negative environmental impact. This review article presents an overview of the existing methods to recycle the cumulating composite wastes containing carbon fibre and glass fibre, with emphasis on fibre recovery and understanding their retained properties. Carbon and glass fibres are assessed via focused topics, each related to a specific treatment method: mechanical recycling; thermal recycling, including fluidised bed and pyrolysis; chemical recycling and solvolysis using critical conditions. Additionally, a brief analysis of their environmental and economic aspects are discussed, prioritising the methods based on sustainable values. Finally, research gaps are identified to highlight the factors of circular economy and its significant role in closing the life-cycle loop of these valuable fibres into re-manufactured composites.

Although there is no doubt that composite materials are the future of lightweight structures and components, most of composites currently produced are made from thermoset polymers, which are not able to be recycled or reprocessed. In contrast, thermoplastic polymers offer the possibility to recycle and reprocess and when combined with a fibrous reinforcement, provide interesting mechanical properties. This work reviews the production of two thermoplastic preimpregnated materials in a tape form, one of which is produced on new prototype equipment developed in our laboratories. The method for the production of tape is described, and the prepregs presented here were subjected to two processing techniques. The first processing method, pultrusion, is an efficient and autonomous method to produce composite profiles, marking itself as a continuous and cost-effective way to produce these materials. Pultrusion bars were then subjected to heated compression moulding, a process that allows to obtain more complex-shaped parts. The second method, heated compression moulding, is a relatively simple process which was used to obtain composite laminates. The pultrusion bars and composite laminates were then subjected to mechanical testing to evaluate the levels of consolidation of the final material. A microscope testing was also carried out to analyse the dispersion of fibres and polymer, as well as the amount of voids present in the composite., Agência Nacional para a Inovação - ANI, Projeto ADD.CompFiber 69603

Fibre-reinforced polymeric composite materials are becoming substantial and convenient materials in the repair and replacement of traditional metallic materials due to their high stiffness. The composites undergo different types of fatigue loads during their service life. The drive to enhance the design methodologies and predictive models of fibre-reinforced polymeric composite materials subjected to fatigue stresses is reliant on more precise and reliable techniques for assessing their fatigue life. The influences of fibre volume fraction and stress level on the fatigue performance of glass fibre-reinforced polyester (GFRP) composite materials have been studied in the tension–tension fatigue scenario. The fibre volume fractions for this investigation were set to: 20%, 35%, and 50%. The tensile testing of specimens was performed using a universal testing machine and the Young’s modulus was validated with four different prediction models. In order to identify the modes of failure as well as the fatigue life of composites, polyester-based GFRP specimens were evaluated at five stress levels which were 75%, 65%, 50%, 40%, and 25% of the maximum tensile stress until either a fracture occurred or five million fatigue cycles was reached. The experimental results showed that glass fibre-reinforced polyester samples had a pure tension failure at high applied stress levels, while at low stress levels the failure mode was governed by stress levels. Finally, the experimental results of GFRP composite samples with different volume fractions were utilized for model validation and comparison, which showed that the proposed framework yields acceptable correlations of predicted fatigue lives in tension–tension fatigue regimes with experimental ones.

The sudden occurrence of an earthquake induces a liquefaction effect on foundation soil, which causes a substantial increase in the uplift pressure acting on piles and causes structural damage to superstructures. This forms the basis of the necessity of experimenting with the behaviour of piles subjected to uplift loads and predicting their load-carrying capacity or resistance. Fibre-reinforced polymer (FRP) wraps are widely used for strengthening and retrofitting piles subjected to damage. The current study is aimed at determining the uplift load-carrying capacity or resistance of piles wrapped with basalt fibre-reinforced polymer (BFRP) and glass fibre-reinforced polymer (GFRP) sheets by experiment. Preliminary tests were conducted to identify the influence of BFRP and GFRP wraps on the mechanical strength properties of concrete. The mechanical strength of the specimen with the double wrapping of basalt and glass fibres in the perpendicular direction outperformed all other specimens. Moreover, the piles were wrapped with laminates and experimented on for their uplift capacity in dry and submerged conditions. The results indicate a considerable improvement in the uplift resistance of the piles compared with the unconfined piles. The BFRP and GFRP wraps improved the uplift resistance of the piles by 35.56% and 15.56%, respectively, higher than the unconfined pile for dry conditions. The angle of the interfacial friction in dry and submerged states was observed to be the maximum for the perpendicular direction for both of the FRP wraps, and the failure modes were compared. The simulated model showed a significant correctness for determining the uplift resistance of FRP-wrapped piles in dry and submerged states. The degree of agreement in the dry condition for the experimental results and finite element method was more than 94% for all fibre wraps.

The present investigation was conducted on the low-speed impact response of quasi-isotropic [±45/0/90°]xs hybrid composite through laboratory level experimental tests. The purpose was to understand the behaviour that the different stacking sequences of hybrid glass/carbon fibre composites has on the ability of the material to sustain loads during low-speed impact events without developing critical structural failure in the material and improving the impact energy absorption properties, which is a relevant matter in aerospace and automotive industries. Drop-weight impact tests were carried out on two different laminates, with different stacking sequences, each of which were 16 symmetric inter-ply hybrid laminates named GC [+45G/−45C/0G/90C]4s and, respectively, G-C [+45G/−45G/0G/90G/+45C/−45C/0C/90C]2s, where G stands for glass fibre and C for carbon fibre. Both were comprised of epoxy matrix reinforced carbon/E-glass fibre woven fabric composites. The outcome of changing the hybrid stacking sequence, on the impact performances, was discussed. The damage morphologies and local failure mechanisms were analysed using visual inspection and a high-resolution laser scanner. Under 33 J impact energy, both tested hybrid composites exhibited approximately 10 kN peak load. Nevertheless, one key parameter, the time to peak load, significantly changed; the damage initiation threshold for GC samples occurred immediately before 6 kN, whereas for G-C samples this threshold appeared much earlier. This type of behaviour was partly connected to the delay in the propagation of delamination and fibre breakage, which was influenced by the high elastic energy absorption of the carbon fibres when compared with the glass fibres. The absorbed energy was higher for GC configuration, whereas a higher DI was observed for samples G-C indicating that a high percentage of the total energy was dissipated through the propagation of in-plane and out-of-plane fibre/matrix cracks. No perforation was observed on either configuration; nevertheless, the damage area significantly changed both in size and appearance from one configuration to another.

Roof garden arrangements, which have emerged in recent years based on environmentally friendly approaches, not only increase urban aesthetics but are also a design approach that contributes to the solution of problems caused by climate change. In this study, the filtration performance of different geotextile materials was investigated based on the extensive roof garden model. The studies related to the research were carried out as an open field pot experiment in Ege University Bayindir Vocational School. Crassula ovata from succulent group plants was used as plant material. 3 filtration materials were tested as filter layers, namely glass fibre, raw cotton, and polypropylene fabric. Various statistical analyses were applied to determine the effectiveness of the filtration materials in extensive roof garden applications. According to statistical significance levels it can be said that the use of polypropylene fabric as filtration material would be more advantageous compared to alternative geotextile materials.

The goal of the European Union is to make strides towards a circular economy. This means recycling or re-using as much of the material in the economic system as possible. The wind industry faces a great challenge in the years to come as huge quantities of increasingly larger wind turbines reach the end of their service-life. When old wind turbines have been decommissioned, most parts are scrapped and recycled into other applications. The turbineblades however are made from glass- and carbon fibre polymers and are not as easily recycled. Recent bans of putting the blades into landfills steer the industry toward finding new applicationfor the old wind turbine blades. Re-purposing the blades as bridges, shelters, houses and towers has been suggested, as well as re-cycle the material or recover the blades as energy. Regardless of what method is preferred, the wind turbine blades need to be transported to a re-purpose or recycling facility. Because of the distribution of wind turbines within countries, the optimal location of such facilities can be hard to evaluate. The centre-of-gravity method (evaluating the centre-of-mass) has been suggested as a way of evaluating the optimal location of such facilities. The method is built upon the assumption that the wind turbine blade can be easily downsized, transported and accommodated in a single transport. In order to achieve this, the present thesis has compared and evaluated different methods of segmenting the wind turbine blade (mechanical, thermal and chemical) as well as different loading and compressing methods. The mechanical separation methods tend to be more suitable than the thermal and chemical counterparts. The choice of loading methods is dictated by the resulting fraction size of the wind turbine blade after separation. The mass density of the resulting blade could be increased with a suitable way of compression (hydraulic or gravity).

Structural health monitoring of composite structures enables early damage detection to prevent critical component failure. Surface-mounted strain gauges are commonly applied to monitor the integrity of composite structures in highly loaded areas. However, strain gauges can only measure strain on the structure's surface and are exposed to environmental influences. Within this paper, fully integrated carbon nanotube thin-film sensors for strain and damage sensing in glass fibre reinforced polymers (GFRP) via electrical resistance measurements are presented. Single wall carbon nanotube epoxy thin-films were manufactured using a manual film applicator, partially pre-cured, placed on dry glass fabrics and infused in a resin transfer moulding process. The mechanical properties of the composites and strain sensing capabilities of the integrated sensors were studied for various load cases and different laminate lay-ups. Results of quasi-static and step-wise three-point bending and tensile tests show that the integrated films allow for localised strain measurements in GFRP without significant loss of mechanical properties. Open hole tensile tests proof the ability to monitor local strain and damage in highly loaded areas enabling failure prediction via threshold resistance change values. The proposed thin-films enable a tailored strain and damage monitoring of GFRP offering the possibility for measurements at different material depths, over large sections or selectively in highly loaded areas. The manufacturing process is easily automatable and suitable for large scale manufacturing. Deutsche Forschungsgemeinschaft (DFG)

In liquid composite molding (LCM) processes a catalyzed resin is forced to flow through a dry fibrous preform, opportunely arranged within a mold. The pressure gradient, positive or negative depending on the particular process, drives the uncured liquid flow at a flow rate which relies on fluid viscosity and preform porosity and permeability. Nowadays, sustainability reasons are pushing the market to the wider usage of natural fibers, such as hemp, jute, flex among others, as an interesting alternative to traditional glass and carbon artificial textiles. This manuscript describes an experimental/numerical approach to analyze the preform permeability and the impregnation flow in the LCM process using different textiles, based on glass, carbon and natural fibers. Unidirectional flow tests were performed using a laboratory scale LCM setup, constituted by a sensed mold in order to dielectrically monitor impregnation and saturation flows. The position of the unsaturated flow front was detected also by means of a camera monitoring the resin flow though milled eyelet sealed using transparent material. The permeability was also numerically inferred using the FlowTex software for all the investigated cases. Numerical and experimental outcomes were finally compared and discussed.

The study considers the mechanical properties and temperature resistance of partially pyrolysed composites reinforced with various fibres. The composites were prepared by pyrolysis at 650 °C, where only partial conversion of the polymer to the inorganic SiOC structure takes place in the matrix. Such a hybrid matrix bears resemblance to polymeric materials in a density and Young's modulus, but oxidation resistance and creep behaviour are closer to silicate glasses. Pyrolysis also ensures that the whole composite material is non-flammable with very low potential for releasing toxic gases during a fire. Three types of glass fibres (E-glass, R-glass, E-CR-glass fibres), two types of basalt fibres, and two types of high-strength (HS) carbon fibres were used as reinforcements. The mechanical properties - Young's and shear moduli, flexural strength, and fracture toughness - were measured at room temperature. Thermogravimetric measurements and creep tests of these composites allowed estimation of their temperature resistance and fire resistance. The results obtained suggest that the materials under investigation can be applied as panels or shells in the building industry and in transportation facilities.

This study was focused on the development of hybrid composed using orange peel particulate dispersed in an unsaturated polyester resin reinforced with chopped strands of E-glass fibers. Orange peel particulate of about 350µm sieve size, of varying weight percentage (3, 6, 9,12 and 15) wt.% and E-glass fiber of constant weight percentage 25.1wt% was used as reinforcements in a polyester matrix. The effect of the orange peel particulate on the physical and mechanical properties of the resulting composite such as tensile strength, bending strength, impact strength and hardness strength was investigated. The results showed remarkable improvement in mechanical properties with increase in percentage of particulate reinforcement. Tensile strength varies from 50.0 to 62.6 MPa, Hardness values varies between 28.6 and 40.8HRB, Impact energy at room temperature, varies between 5.0 to 7.4 Joules, as a function of fiber weight fractions and the flexural strength varies from 74.0 to 85.2 MPa. The best mechanical properties were obtained at 15 Wt.% particulate reinforcements. The results of the physical tests show that the water absorption increases as the weight percentage of the particulate reinforcement increases and the same condition also holds for the density.

Microwave non-destructive testing (NDT) has received extensive attention in recent years owing to its advantages of non-contact and one-sided inspection, no need for a coupling medium or sensors attached on the object surface, low power, good repeatability, a relatively easy measurement setup and no ionising radiation hazards. As an alternative method of traditional X-ray imaging and ultrasonic testing, it has been used for monitoring and evaluation of the structural integrity of fibrereinforced polymer composite structures. This paper provides a comprehensive overview of the microwave-based techniques for glass fibre composites, including material characterisation, strain sensing, surface profiling, near-field and far-field damage detection. First, the electromagnetic properties of glass fibre composites and the microwave penetration capability associated are thoroughly discussed. Then, based on the detection principles, the microwave NDT methods are classified into five categories: near-field detection with an open-ended probe (coaxial line/waveguide), near-field resonance methods, far-field sensing methods, focusing methods and microwave-based thermography (integration with another NDT method). The experimental setup, applications and limitations of each technique are reviewed in detail. Finally, discussions on the research trends are presented, including more accurate theoretical models, damage classification, use of the RFID technique, automated inspection and use in additive manufacturing.

Glass fibre-reinforced polyphenylene sulphide composites were prepared by hot-pressing glass fibre fabrics and polyphenylene sulphide resins. The effects of different polyphenylene sulphide resin forms on the properties of the composites were investigated using scanning electron microscopy, dynamic mechanical analyser, pendulum impact tester and universal testing machine. The results showed that different polyphenylene sulphide resin forms had nearly no effect on the glass transition temperature of the composites, which are all located at about 100 °C. Compared with other polyphenylene sulphide composites, the bending strength of polyphenylene sulphide film composites was the highest, reaching 314.58 MPa, and the impact strength of polyphenylene sulphide particle composites was the highest, reaching 245.4 KJ/m2. The bending strength and impact strength were calculated using a standard fraction, and the highest standard fraction was obtained when the ratio of polyphenylene sulphide film to particle was 1:2. The impact strength and bending strength could be obtained. The impact strength reached 229.8 KJ/m2, and the bending strength reached 284.16 MPa.

In recent years, there has been an increasing demand for engineering materials that possess good mechanical and thermal properties and are cheap an d environmentally friendly. From an industrial and academic point of view, there is a need to study the heat conductivity of newly developed polymer composites and the influence of porosity on the insulation performance of polymer composites. Experimental and theoretical studies were conducted on mainly sisal/glass fibre gypsum composites with different fibre volumes (0, 20, 25, 30, and 35 wt.%). The outcomes from the theoretical model in ANSYS have shown that there is a high possibility to simulate the experimental work and high accuracy for reflecting the experimental findings. Moreover, the results show that natural fibre polymer composites with a high-volume fraction of natural fibres have higher insulation performance than synthetic polymer composites with the same volume fraction of synthetic fibres. Furthermore, the results suggest and support that the improved performance of natural fibre-based composites was due at least in part to the internal porosity of the fibres.

The limited literature on the cost of various recycling methodologies for thermoset composites sets the background of this work, focusing mainly on the identification of an upper and lower economic value of glass fibre recovered from wind turbine blades recycling. The study briefly reviews the materials used by various original equipment manufacturers (OEM) for wind turbine blades. Successively, it provides an overview of the various recycling methods with interest in recovered materials, mechanical and physical properties, which are used, for estimating a maximum expected value. All recycling processes show a negative effect on mechanical properties with strength loss between 30% and 60%. Process energy demands are reviewed, and considerations are set forward to estimate the minimum cost of operating mechanical, pyrolysis and fluidized bed plants in Germany. Ultimately, current applications of recovered material and related markets are explored. Through interviews and secondary data, it is highlighted that despite the lower mechanical properties, grinded material finds applications in traditional processes, cement kilns and new products. It is also found that pyrolysed fibres can be used as insulation material and oils can be easy to distil. Pyrolysis is a relatively expensive process, thereby, distillation of the oils and energy recovery are necessary enablers towards commercial viability. Mechanically grinded material presents the lowest process cost with ca. €90/tonne, thus, below landfilling and incineration and falling within the attention of private businesses. Numerous markets are available for recovered materials from wind turbine blades, primarily for grinded products and secondly for pyrolysed glass fibre.

A study has been made of mineral admixtures, such as ultra-fine Fly-ash and Metakoalin, and glass fibers and polypropylene fibers, to produce high performance Concrete. Glass fiber is maintained stable by volume by 0.25 percent by cement content in varying fractions (0.5 percent, 0.75 percent & 1.0 percent) and polypropylene fiber. SP 430 is applied to the concrete mix to ensure greater workability. The grade of concrete M70 is used. The cubes, cylinders and beams are casted for different water cement ratios of 0.275%, 0.30% and 1.00%. The strength tests are carried out for 14, 28 days and durability tests are carried for 56 days. The Behavior of the HPC specimens in compressive strength, flexure and splitting tensile strength were calculated. Due to the addition of mineral admixture & fiber volume into the mix, it gives very good performance & Suitable for construction.

High-performance fibre-reinforced polymer composites are important construction materials based not only on the specific properties of the reinforcing fibres and the flexible polymer matrix, but also on the compatible properties of the composite interphase. First, oxygen-free (a-CSi:H) and oxygen binding (a-CSiO:H) plasma nanocoatings of different mechanical and tribological properties were deposited on planar silicon dioxide substrates that closely mimic E-glass. The nanoscratch test was used to characterize the nanocoating adhesion expressed in terms of critical normal load and work of adhesion. Next, the same nanocoatings were deposited on E-glass fibres, which were used as reinforcements in the polyester composite to affect its interphase properties. The shear properties of the polymer composite were characterized by macro- and micromechanical tests, namely a short beam shear test to determine the short-beam strength and a single fibre push-out test to determine the interfacial shear strength. The results of the polymer composites showed a strong correlation between the short-beam strength and the interfacial shear strength, proving that both tests are sensitive to changes in fibre-matrix adhesion due to different surface modification of glass fibres (GF). Finally, a strong correlation between the shear properties of the GF/polyester composite and the adhesion of the plasma nanocoating expressed through the work of adhesion was demonstrated. Thus, increasing the work of adhesion of plasma nanocoatings from 0.8 to 1.5 mJ·m-2 increased the short-beam strength from 23.1 to 45.2 MPa. The results confirmed that the work of adhesion is a more suitable parameter to characterise the level of nanocoating adhesion in comparison with the critical normal load. Vysoce výkonné vlákny vyztužené polymerní kompozity jsou důležité konstrukční materiály založené nejen na specifických vlastnostech výztužných vláken a pružné polymerní matrici, ale také na kompatibilních vlastnostech kompozitního mezifáze. Nejprve byly na planární substráty oxidu křemičitého, které úzce napodobují E-sklo, naneseny plazmové nanopovlaky bez obsahu kyslíku (a-CSi: H) a vázající kyslík (a-CSiO: H). K charakterizaci nanopovlakové adheze vyjádřené z hlediska kritického normálního zatížení a práce adheze byl použit nanorozprašný test. Dále byly stejné nanopovlaky naneseny na vlákna E-glass, která byla použita jako výztuhy v polyesterovém kompozitu, aby se ovlivnily jeho mezifázové vlastnosti. Smykové vlastnosti polymerního kompozitu byly charakterizovány makro- a mikromechanickými zkouškami, jmenovitě zkouškou krátkým paprskem ve smyku pro stanovení pevnosti krátkého paprsku a zkouškou tlakem z jednoho vlákna pro stanovení mezifázové smykové pevnosti. Výsledky polymerních kompozitů ukázaly silnou korelaci mezi pevností krátkého paprsku a mezifázovou pevností ve smyku, což dokazuje, že oba testy jsou citlivé na změny adheze vláknových matric v důsledku odlišné povrchové úpravy skleněných vláken (GF). Nakonec byla prokázána silná korelace mezi smykovými vlastnostmi GF / polyesterového kompozitu a adhezí plazmatického nanopovlaku vyjádřenou prostřednictvím práce adheze. Zvyšování práce adheze plazmových nanopovlaků z 0,8 na 1,5 mJ · m-2 tedy zvýšilo sílu krátkého paprsku z 23,1 na 45,2 MPa. Výsledky potvrdily, že práce adheze je vhodnějším parametrem pro charakterizaci úrovně adheze nanopovlaku ve srovnání s kritickým normálním zatížením.

Basalt fibre is a promising mineral fibre that has high potential to replace synthetic based glass fibre in today’s stringent environmental concern. In this study, friction and wear characteristics of glass and basalt fibres reinforced epoxy composites were studied and comparatively evaluated at two test stages. The first stage was conducted at fixed load, speed and distance under three different conditions, adhesive, abrasive and erosive wear, wherein each composite specimens slide against steel, silicon carbide, and sand mixtures, respectively. The second stage was conducted involving different types of adhesive sliding motions against steel counterpart, unidirectional and reciprocating motion, with the former varied at pressure—velocity (PV) factor, 0.23 MPa·m/s and 0.93 MPa·m/s, while the latter varied at counterpart’s configuration, ball-on-flat (B-O-F) and cylinder-on-flat (C-O-F). It was found that friction and wear properties of composites are highly dependent on test conditions. Under 10 km test run, Basalt fibre reinforced polymer (BFRP) composite has better wear resistance against erosive sand compared to Glass fibre reinforced polymer (GFRP) composite. In second stage, BFRP composite showed better wear performance than GFRP composite under high PV of unidirectional sliding test and under B-O-F configuration of reciprocating sliding test. BFRP composite also exhibited better friction properties than GFRP composite under C-O-F configuration, although its specific wear rate was lower. In scanning electron microscopy examination, different types of wear mechanisms were revealed in each of the test conducted.

Thermo-oxidative aging of dipentaerythritol (DPE) stabilized, glass fibre reinforced PA66 compounds was studied at 200°C. The influence of DPE as a thermo-oxidation stabilizer on the retention of tensile properties, molecular weight, crystallinity, oxidized layer thickness as well as the specimen surface and fracture morphology was analysed. Moreover, the impact of DPE on the intrinsic humidity inside the test specimens before aging was examined due to its hygroscopic behaviour. The reduction of the extractable amount of DPE from test granules over the aging time proved the existence of chain extension or crosslinking reactions between the polyamide or its degradation products and DPE. Whereas DPE improves the retention of mechanical characteristics during aging only slightly, the combination of DPE and glass fibres reaches retention of mechanical characteristics above 50 % after 1000 h of aging at 200°C in air. DPE raises the intrinsic humidity during processing and before aging resulting in an increase of PA66 degradation during processing and in the first aging phase due to additional hydrolysis. Both the ensuing shorter chain length and water-induced post-crystallisation give rise to higher crystallinity after processing, increasing the oxygen diffusion limitation which results in slower thermo-oxidation. In addition, DPE accelerates the formation of the oxidized layer on the PA66 surface but slows down its growth during the later aging phase.

Automobilska industrija jedna je od najvažnijih grana industrije u svijetu, a potreba za zamjenom konvencionalnih metalnih materijala sve je veća zbog nametnutih visokih zahtjeva koje proizvođači moraju zadovoljiti. Najvažniji zahtjev je smanjenje emisije štetnih plinova koji se postiže upotrebom manje količine energije potrebne za vožnju. Manja masa vozila znači i manju potrošnju energije. Pravilnim odabirom materijala, a koji će ujedno zadovoljiti svojim mehaničkim svojstvima te otpornošću na koroziju i atmosferilije, može se značajno smanjiti ukupna masa vozila. Dobar odabir su polimerni kompoziti, materijal koji zadovoljava sve kriterije i ima mogućnost projektiranja svojstva. U ovom završnom radu prikazan je jedan od postupaka izrade kompozitnih automobilskih dijelova, a u te svrhe izrađen je krovni spojler postupkom ručnog laminiranja. U kompozitu od kojeg je spojler izrađen korišteno je ojačanje staklenim vlaknima, a materijal matrice je poliesterska smola. Opisan je postupak izrade od prototipa, kalupa do gotovog proizvoda kao i korišteni materijali. The automotive industry is one of the largest industry branches in the world. Comparatively, the urgency for the replacement of conventional materials is also growing ever-larger, as the car manufacturers have to meet the strict and levied demands. The most important demand is the reduction of the exhaust of harmful gasses, which is achieved by lowering the power consumption needed to drive the vehicle. By appropriately choosing materials which simultaneously meet the required mechanical standards and offer resistance to corrosion and weather effects, the manufacturers can significantly lower the total mass of the vehicle. Such materials include polymer composites, which meet all standards and are customizable. This Bachelor thesis presents one of the processes of composite automotive part production. A roof spoiler was manually laminated and constructed for the thesis purpose. The composite used in the construction of the spoiler was reinforced with glass fibres and the material used for the matrix was polyester resin. In addition to this, the manufacturing process from the prototype, to the mould and up until the finished product, as well as the materials used are presented.

The heat-treated apricot shell can be utilized as coarse aggregates for producing sustainable bio-based lightweight concrete with good compressive strength but poor tensile strength. In order to improve the tensile properties of apricot shell concrete (ASC), the effects of polypropylene (PP) fibre, glass (G) fibre and basalt (B) fibre at various volume fractions (Vf) (0.25%, 0.5% and 0.75%) on the performance of ASC were investigated. The results indicated that the fibre type had no significant effect on the physical properties of ASC such as slump, density, water absorption and permeable porosity. However, the slump of ASC decreases with an increase in fibre content. The B fibre has a better improvement in mechanical properties than the PP fibre and G fibre thanks to the better elastic modulus and tensile strength. When the Vf was 0.5%, the compressive strength, splitting tensile strength, flexural strength and modulus of elasticity of ASC reinforced with B fibre were increased by 16.7%, 29.1%, 29.2%, and 18.1%, respectively, compared to ASC without any fibres. The magnesium sulfate attack results showed that the incorporation of the B fibre decreased the mass loss and compressive strength of ASC exposed to a MgSO4 solution for 6 months because the fibre arrested the microcracks caused by the expansive stress. It is concluded that the mechanical properties of bio-based ASC and its resistance to magnesium sulfate attack can be significantly improved by incorporating 0.5% B fibre.

Continuous pressure put on researchers all over the world these days to design materials of improved properties create opportunities to study new methods of production in conjunction with entirely new and innovative materials such as alloys or composites. The authors in the current research manufactured aluminium reinforced with glass fibre (GF) using metallurgical synthesis, which is an unconventional and not sufficiently studied method of production. The composites with 1, 2 and 5 wt.% of glass fibre were produced with additional material obtained using consolidation of aluminium powder in extrusion process as reference material with 5 wt.% of glass fibre. All the materials were subjected to series of tests in order to determine their microstructure, density, electrical properties, hardness and susceptibility to plastic working in the compression test. It was found that glass fibre during metallurgical synthesis of aluminium composite partially melted and thus did not reinforce the material as well as during extrusion, which has been observed not only in the scanning electron microscope (SEM) and energy-dispersive X-ray (EDX) analysis but also in the analysis of macroscopic physical and mechanical properties. Based on the analysed samples, it may be stated that electrical conductivity of the samples obtained via metallurgical synthesis is higher than might be estimated on the basis of the rule of mixtures and glass fibre content and concerning the sample with 5 wt.% of GF is higher (32.1 MS/m) than of the reference material obtained in extrusion process (30.6 MS/m). Similar situation has been observed in terms of hardness of the tested samples where a minor increase in hardness was noticeable as the amount of glass fibre increased in the composites obtained by metallurgical synthesis. It is believed to be related to the melting of glass fibre, which reduced the volume fraction of GF containing mainly silicon oxides and their diffusion into the aluminium matrix, thus causing solid solution strengthening.

The objective of the project was to investigate the long-term hot/wet performance of Glass fibre Reinforced Epoxy composites used for industrial pipe systems. A large part of the work consisted of the development of test methods for both macroscopic and microscopic level. This resulted in new test methods that were found to be as discriminative as the proven internal ‘finger-print tests’ of FPI, a much more elaborative test. A series of glass fibre products was evaluated both for their resistance to storage in hot environments (‘thermal ageing’) and to long-term hot-wet exposure up to temperatures of 125 C. Furthermore, Carbon Fibre Reinforced Epoxy (CFRP) and Glass Fibre Reinforced Epoxy (GRE) were monitored for their response to long-term hot/wet exposure up to a temperature of 150 C.

The objective of the project was to investigate the long-term hot/wet performance of Glass fibre Reinforced Epoxy composites used for industrial pipe systems. A large part of the work consisted of the development of test methods for both macroscopic and microscopic level. This resulted in new test methods that were found to be as discriminative as the proven internal ‘finger-print tests’ of FPI, a much more elaborative test. A series of glass fibre products was evaluated both for their resistance to storage in hot environments (‘thermal ageing’) and to long-term hot-wet exposure up to temperatures of 125 C. Furthermore, Carbon Fibre Reinforced Epoxy (CFRP) and Glass Fibre Reinforced Epoxy (GRE) were monitored for their response to long-term hot/wet exposure up to a temperature of 150 C.

The additive manufacturing represents a new production method of composites reinforced with a continuous fibre. In recent times, the material produced by this new manufacturing method constituted a replacement for conventional materials&mdash, e.g., steel in many technical areas. As the research on FRTP composites is currently under way, the purpose of this article is to add information to the mosaic of studies in this research area. The scientific articles published until now have focused especially on mechanical testing, such as tensile and bending mechanical testing and their assessment. Therefore, the authors decided to carry out and assess the impact test of the FRTP composites produced by 3D printing because this area offers a large extent of research activities. We observed the influence of the reinforcement in the form of the micro-fibre carbon in the thermoplastic (Onyx) or a continuous reinforcement fibre in the lamina on the specimen&rsquo, s behaviour during the impact load processes. The results of the experimental measurements show that the presence of a continuous fibre in the structure significantly affects the strength of the printed specimens, however, the design process of the printed object has to take into account the importance of selecting a suitable fibre type. The selection of a suitable strategy for arranging the fibre in the lamina and the direction of the impact load against the position of the fibre seem to be very important parameters.

The ever increasing size of wind turbines has given rise to a need for robust glass to carbon joint designs. This study investigates the effect of different ply layups on the static and fatigue behaviour of hybrid glass/carbon fibre composite joints. Uni-directional carbon fibre prepreg was co-cured to 8H glass prepreg using an overlap to thickness ratio of 20:1, where four joint designs were examined: scarf, interleaving and two forms of double scarf. The joints were tested statically in uniaxial tension and dynamically in tension-tension fatigue. Finite element analysis has been performed to provide insight into stress distributions within each joint. The double scarf joint (with glass on the outside) was found to perform best in fatigue and static tension, while the interleaving joint performed second best in fatigue in static tension but poorest in fatigue. For joint designs that will be used under highly stressed cyclic loading conditions, the current study indicates that static tests alone are a poor indicator of the joint performance and fatigue tests are required.

Clayey soils endure adverse changes in strength and volume due to seasonal changes in moisture content and temperature. It has been well recognised that high cement content has been successfully employed in improving the mechanical properties of clayey soils for geotechnical infrastructural purposes. However, the environmental setbacks regarding the use of high cement content in soil reinforcement have necessitated the need for a greener soil reinforcement technique by incorporating industrial by-product materials and synthetic fibres with a reduced amount of cement content in soil-cement mixtures. Therefore, this study presents an experimental study to investigate the mechanical performance of polypropylene and glass fibre-reinforced cement-clay mixtures blended with ground granulated blast slag (GGBS), lime and micro silica for different mix compositions and curing conditions. The unconfined compressive strength, linear expansion and microstructural analysis of the reinforced soils have been studied. The results show that an increase in polypropylene and glass fibre contents caused an increase in unconfined compressive strength but brought on the reduction of linear expansion of the investigated clay from 7.92% to 0.2% at fibre content up to 0.8% for cement-clay mixture reinforced with 5% Portland cement (PC). The use of 0.4&ndash, 0.8% polypropylene and glass fibre contents in reinforcing cement-clay mixture at 5% cement content causes an increase in unconfined compressive strength (UCS) values above the minimum UCS target value according to American Society for Testing and Materials (ASTM) 4609 after 7 and 14 days curing at 20 &deg, C to 50 &deg, C temperature. Therefore, this new clean production of fibre-reinforced cement-clay mixture blended with industrial by-product materials has great potential for a wide range of applications in subgrade reinforcement.

This study investigates the fracture properties of high performance cementitious composites (HPCC) with four different types of fibres and with volume fraction content 3%. The four fibres are steel hooked end (S), polypropylene crimped (PP), basalt chopped (B), and glass (G) fibres. The tests were carried out in accordance with the RILEM recommendations. In order to examine the fresh properties of HPCC the slump flow tests were performed. Twelve fibre reinforced HPCC beam specimens with notch were cast and tested using central point loading experiments. In addition, experimental tests of the compressive strength and splitting tensile strength were carried out. The test results made it possible to obtain representative fracture parameters, such as the equivalent strengths, residual strengths, and fracture energy of fibre reinforced HPCC. The S fibre specimens showed the best performance in terms of workability, compressive strength, tensile splitting strength, and fracture energy at large deflection. On the other hand, G fibre specimens exhibited the best performance in terms of flexural strength, equivalent flexural strength at higher deflection, and residual flexural strength at lower deflection. In terms of equivalent flexural strength at lower deflection and residual flexural strength at higher deflection, basalt fibre specimens performed the best. On the contrary, polypropylene fibre reinforced beam specimens revealed the highest deflection capacity.

Six impact energy values, ranging from 2.5 J to 10 J, were applied to study the impact properties of neat epoxy and bamboo composites, while six impact energy values, ranging from 10 J to 35 J, were applied on bamboo/glass hybrid composites. Woven glass fibre was embedded at the outermost top and bottom layer of bamboo powder-filled epoxy composites, producing sandwich structured hybrid composites through lay-up and molding techniques. A drop weight impact test was performed to study the impact properties. A peak force analysis showed that neat epoxy has the stiffest projectile for targeting interaction, while inconsistent peak force data was collected for the non-hybrid composites. The non-hybrid composites could withstand up to 10 J, while the hybrid composites showed a total failure at 35 J. It can be concluded that increasing the filler loading lessened the severity of damages in non-hybrid composites, while introducing the woven glass fibre could slow down the penetration of the impactor, thus lowering the chances of a total failure of the composites.

The growing use of carbon and glass fibres has increased awareness about their waste disposal methods. Tonnes of composite waste containing valuable carbon fibres and glass fibres have been cumulating every year from various applications. These composite wastes must be cost-effectively recycled without causing negative environmental impact. This review article presents an overview of the existing methods to recycle the cumulating composite wastes containing carbon fibre and glass fibre, with emphasis on fibre recovery and understanding their retained properties. Carbon and glass fibres are assessed via focused topics, each related to a specific treatment method: mechanical recycling; thermal recycling, including fluidised bed and pyrolysis; chemical recycling and solvolysis using critical conditions. Additionally, a brief analysis of their environmental and economic aspects are discussed, prioritising the methods based on sustainable values. Finally, research gaps are identified to highlight the factors of circular economy and its significant role in closing the life-cycle loop of these valuable fibres into re-manufactured composites.

U ovome radu prikazana je konstrukcija naprave za doziranje smole, te naprave za dodavanje vlakana kod izrade spremnika pod tlakom postupkom kontinuiranog namatanja vlakana koje su prilagođene za primjenu s postojećim robotskim sustavima. Prikazana je i analiza postojećih rješenja koja su dostupna na tržištu. U konstrukcijskoj razradi prikazana je konstrukcija svih potrebnih elemenata naprava za doziranje smole i dodavanje vlakana. Dijelovi naprava koji su u direktnom dodiru sa staklenim vlaknima izrađeni su iz materijala otpornog na abrazijsko djelovanje, odnosno trošenje. Danim konstrukcijskim rješenjima naprava želi se postići brza i efikasna izrada spremnika pod tlakom, te brzo i jednostavno čišćenje i održavanje samih naprava. This thesis paper presents the construction of a resin dispensing device, and a device for the addition of fibres in the production of pressurised containers by the continuous fibre winding process adapted for use with existing robotic systems. An analysis of existing solutions available on the market is also presented. In the device design elaborations the construction of all necessary elements for the resin dosing as well as for the addition of fibre is presented. Parts of devices that are in direct contact with glass fibres are made from materials resistant to abrasive activity or wear. By utilizing the design solutions provided, the device is able to achieve rapid and efficient production of pressurised containers, quick and easy cleaning and maintenance of the devices themselves.

The rapid utilization of carbon fibre reinforced composite (CFRC) and glass fibre reinforced composite (GFRC) in main sectors, such as automobile, aerospace, wind turbines, boats and sport parts, has gained much attention because of its high strength, light weight and impressive mechanical properties. Currently, the increasing amount and handling of composite waste at their end-of-life (EoL) has a negative impact on resources conservation and the environment. Pyrolysis, a two-step process, appeared as most viable process to recover not only valuable materials but also produce fuel and chemicals. However, the testing facilities and optimized operation of composite waste in pyrolysis processes to produce materials with low energy consumption and acceptable mechanical properties are still under development and discussion before commercialization. The aim of this article is to review the studies on CFRC/GFRC recycling via pyrolysis processes and highlight their technical challenges and re-use possibilities in high performance composites. The forthcoming commercialization challenges and respective market potential to recyclates using the pyrolysis process will be addressed. This study will also introduce the strong connection between recycling and re-usability of fibres which would help to explain the concept of circular economy and cradle-to-cradle approach. Finally, based on updated studies and critical analysis, research gaps in the recycling treatments of fibrous composite waste using pyrolysis processes are discussed with recommendations.

There are forecasts for the exponential increase in the generation of carbon fibre-reinforced polymer (CFRP) and glass fibre-reinforced polymer (GFRP) composite wastes containing valuable carbon and glass fibres. The recent adoption of these composites in wind turbines and aeroplanes has increased the amount of end-of-life waste from these applications. By adequately closing the life cycle loop, these enormous volumes of waste can partly satisfy the global demand for their virgin counterparts. Therefore, there is a need to properly dispose these composite wastes, with material recovery being the final target, thanks to the strict EU regulations for promoting recycling and reusing as the highest priorities in waste disposal options. In addition, the hefty taxation has almost brought about an end to landfills. These government regulations towards properly recycling these composite wastes have changed the industries’ attitudes toward sustainable disposal approaches, and life cycle assessment (LCA) plays a vital role in this transition phase. This LCA study uses climate change results and fossil fuel consumptions to study the environmental impacts of a thermal recycling route to recycle and remanufacture CFRP and GFRP wastes into recycled rCFRP and rGFRP composites. Additionally, a comprehensive analysis was performed comparing with the traditional waste management options such as landfill, incineration with energy recovery and feedstock for cement kiln. Overall, the LCA results were favourable for CFRP wastes to be recycled using the thermal recycling route with lower environmental impacts. However, this contradicts GFRP wastes in which using them as feedstock in cement kiln production displayed more reduced environmental impacts than those thermally recycled to substitute virgin composite production.

Technical thermoplastic materials (e.g., PEEK, PPA and POM) are widely used for tribological applications combined with different filler systems (e.g., glass- or carbon fibres) because of their excellent mechanical properties. The friction and wear behaviour of thermoplastics can be specifically improved by solid lubrication systems such as graphite, PTFE and MoS2. Besides these systems, others such as WoS2 and MnS are becoming scientifically interesting. This work investigates the influence of different solid lubricants—alternative metal sulphides and polymer-based—in combination with different glass fibre contents on the tribological behaviour of unfilled PEEK and glass fibre-filled PPA. For this purpose, compounds were produced and injection-moulded into tribological test specimens that were subsequently tested. It is particularly evident for both matrix materials that the solid lubricant SLS 22 shows a 25% wear rate reduction when compared to MoS2 and, in addition, the proportion of fibre content in PPA shows an additional wear rate reduction by a factor of 10. The friction level could be kept at a similar level compared to the usually utilised solid lubricants. The investigations showed the potential use of metal sulphide filler systems in high-performance thermoplastic with enhanced tribological properties as alternatives to the well-established solid lubricants.

This paper presents a novel methodology for predicting the dielectric constant of three-dimensional woven glass fibre-reinforced composites. A well-established approach of deriving the effective dielectric constant is the dielectric mixing formulae (rule of mixtures based), which either provide a single value or offer upper and lower bounds. For composites with three-dimensional fibre architecture, an accurate model considering the three-dimensional effect is needed. Here, the anisotropic effect is revealed using electromagnetic simulation to extract the effective dielectric constant of a model material with unidirectional fibres, which are aligned or orthogonal to the electric field. The rule of mixtures based formulae are evaluated. The most suitable formula selected for each case is then extended to a general case with arbitrary fibre orientation and is further used to characterise the capacitor element of an electromagnetic model for 3D woven composites. The proposed method is compared to measurements to demonstrate the improved accuracy.

Due to the environmental impacts resulting from the production of Ordinary Portland cement (OPC), the drive to develop alternative binders that can totally replace OPC is gaining huge consideration in the construction field. In the current study, attempt was made to determine the strength characteristics of glass fibre-reinforced fly ash based geopolymer concrete. Sodium hydroxide (NaOH) and sodium silicate (Na 2 SiO 3 ) were used as alkaline solutions (for activation of geopolymer reaction) at 12, 16, 20 M. Glass fibres were added to the geopolymer concrete in varying proportions of 0.1–0.5% (in steps of 0.1%) by weight of concrete. A constant weight ratio of alkaline solution to fly ash content of 0.43 was adopted for all mixes. British standard concrete test specimens were cast for measuring compressive strength, split-tensile strength, and flexural strength. Concrete specimens were cured by heating in oven at 90 °C for 24 h and natural environment, respectively. From the results, thermally cured concrete samples had better mechanical properties than the ambient (natural) cured samples. Thermally cured concrete specimen, containing 0.3% glass fibre and 16 M NaoH, achieved a maximum compressive strength of 24.8 MPa after 28 d, while naturally cured samples achieved a strength of 22.2 MPa. There was substantial increase in tensile strength of geopolymer concrete due to the addition of glass fibres. Split tensile strength increased by 5–10% in glass fibre-reinforced geopolymer concrete, containing 0.1–0.5% glass fibre and 16 M NaoH when compared to the unreinforced geopolymer concrete (1.15 MPa).

In this experimental work, the behaviour of unidirectional glass fibre-epoxy composites under a cutting force was studied, in order to better understand the cutting mechanisms of processes involving but not limited to composite materials. Starting from composite panels manufactured by resin infusion process, dedicated specimens were obtained and subjected to a quasi-static punch-shear test. Eight different fibre orientation angles with respect to the direction of the cutting force were considered. For each case, different stress-strain behaviours were observed and discussed. The differences were also investigated, in terms of damage propagation, by means of microscopic observations of the cutting zone.

V okviru zaključne naloge smo spoznavali proces vakuumske infuzije s ciljem ugotavljanja vplivov procesnih parametrov na kakovost izdelanih plošč. Glavni cilj izvedenega eksperimenta je bil ugotoviti nabor parametrov za zagotavljanje najkrajšega proizvodnega časa ter obenem zagotoviti visoko kakovost plošč. Spreminjali smo presek dovodne cevke, temperaturo procesa ter obliko in orientacijo infuzijske tkanine. Za izdelavo kompozita smo uporabili tkanino iz enosmernih steklenih vlaken ter epoksi smolo. Mehanske lastnosti smo testirali s tri-točkovnim upogibnim preizkusom, pri čemer smo izmerili upogibno trdnost, modul elastičnosti in upogibno razteznost v vzdolžni in prečni smeri. Največji vpliv na hitrost infuzije sta imela delovna temperatura ter usmerjenost in oblika infuzijske mrežice. Ugotovili smo, da je najboljša kombinacija za dosego najkrajšega proizvodnega časa in obenem čim manjše zakasnitve impregnacijskih front delovna temperatura 35 C ter zmanjšanje velikosti infuzijske mrežice na sesalni strani. Z upogibnim preizkusom vzorcev smo ugotovili, da se zaradi zmanjševanja debeline plošč od polnilne do sesalne strani povečuje modul elastičnosti in upogibna trdnost. Sprememba procesnih parametrov v raziskanem območju je imela signifikantni vpliv tudi na prečno trdnost plošč, ni pa imela večjega vpliva na vzdolžno trdnost. In the final thesis, we researched the process of vacuum infusion with the aim of determining the influence of process parameters on the quality of the manufactured panels. The main objective of the experiment was to determine a set of parameters to ensure the shortest production time, while at the same time ensuring high quality of the plates. We changed the cross section of the delivery tube, the process temperature, and the shape and orientation of the infusion mesh. One-way fiberglass fabric and epoxy resin were used to make the composite. Mechanical properties were tested with a three-point flexural test. We measured the flexural strength, modulus of elasticity, and flexural elongation in the longitudinal and transverse directions. The greatest influences on the speed of the infusion were the process temperature and the shape and size of the infusion mesh. We found that the best combination to achieve the shortest production time while minimizing the delay of the impregnation fronts is preheating the plates at 35°C and reducing the size of the infusion mesh on the suction side. By flexural testing of specimens, we found that because of the reduction in thickness of the plates from the filling to the suction side, the modulus of elasticity and flexural strength are increased. In the area studied, the change in the process parameters also had a significant effect on the transverse strength of the plates but had no significant effect on the longitudinal strength.

V magistrskem delu je obravnavana problematika obrabe brizgalnega orodja pri brizganju polimera z vsebnostjo steklenih vlaken. Izdelana je podrobna analiza literature, na kateri temelji eksperimentalni del, kjer je obravnavana obrabna obstojnost štirih kavitetnih vložkov različnih toplotnih obdelav in materialov na delovanje taline polimera. Delo temelji na predpostavki, da je stopnja obrabe v posameznih conah kavitetnih votlin različna. Eksperimentalni del naloge je bil izveden na prototipnem orodju, v katerega so bili vgrajeni omenjeni kavitetni vložki. Testiranje je zajemalo 10 000 brizgov, kot brizgani material pa je bil uporabljen termoplast PA66 GF35. Kvantitativni popis stopnje obrabe je izveden s stopnjo hrapavosti Ra in Rz. Za preučevanje prisotnih obrabnih mehanizmov je uporabljena optična mikroskopija in interferomatrija. Največja stopnja obrabe je bila zaznana na ustju kavitetnih vložkov, ki se odraža v popačenju njegove geometrije. Zaznane so bile tudi različne obrabne obstojnosti uporabljenih materialov in toplotnih obdelav. The master’s thesis deals with the problem of the injection mould wear in the process of injecting glass reinforced polymer. The thesis presents a detailed analysis of literature upon which the experimental part is based, where the wear resistance of four cavity inserts of various heat treatments and materials is considered. The work is based upon assumption of a different degree of wear in individual cavity zones. The experimental part was performed on a prototype injection mould in which the said cavity inserts were installed. The test involved 10 000 shots of PA66 GF35 thermoplastic material. Wear rates are quantified with Ra and Rz roughness parameters before and after the experiment was conducted. Optical microscopy and interferometry were also used to observe present wearing mechanisms. The highest wear rate was detected in the region of the tunnel gates of the cavity inserts, which is reflected in the distortion of their geometry. Different wear durability was detected at different materials and heat treatments.

Environmental awareness and trends to develop sustainable resources have directed much research attention towards kenaf fibre as an alternative reinforcement in composite manufacturing. Numerous studies have been conducted on kenaf and its hybrid composites. Most studies were conducted on kenaf/glass hybrid composites compared to other kenaf/synthetic hybrid composites. Similar with other materials, mechanical properties were the fundamental knowledge identified by the researcher. Limited studies conducted on other properties have restricted the use of kenaf composites to non-structural applications. To extend the potential of kenaf composites to automotive exterior or other critical applications, studies on impact properties can be a valuable contribution in the material field. This review discusses the mechanical and low velocity impact properties of kenaf/glass hybrid composites reported previously. Percentage loading of fibre, the angle of orientation in woven fibres and the chemical treatment applied to the fibre before compounding are the three major parameters that affect the mechanical and impact properties of the composites. This review provides insights into the mechanical and impact properties of kenaf/glass hybrid composites for future research.