Glass Fibre

This article aims to determine the environmental performance of China reed fibre used as a substitute for glass fibre as reinforcement in plastics and to identify key environmental parameters. A life cycle assessment (LCA) is performed on these two materials for an application to plastic transport pallets. Transport pallets reinforced with China reed fibre prove to be ecologically advantageous if they have a minimal lifetime of 3 years compared with the 5-year lifetime of the conventional pallet. The energy consumption and other environmental impacts are strongly reduced by the use of raw renewable fibres, due to three important factors: (a) the substitution of glass fibre production by the natural fibre production; (b) the indirect reduction in the use of polypropylene linked to the higher proportion of China reed fibre used and (c) the reduced pallet weight, which reduces fuel consumption during transport. Considering the whole life cycle, the polypropylene production process and the transport cause the strongest environmental impacts during the use phase of the life cycle. Since thermoplastic composites are hardly biodegradable, incineration has to be preferred to discharge on landfills at the end of its useful life cycle. The potential advantages of the renewable fibres will be effective only if a purer fibre extraction is obtained to ensure an optimal material stiffness, a topic for further research. China reed biofibres are finally compared with other usages of biomass, biomaterials, in general, can enable a three to ten times more efficient valorisation of biomass than mere heat production or biofuels for transport.

An experimental investigation was carried out to study the effect of polyamide coatings on the adhesion and moisture absorption behaviour of glass/polyester composites. Glass fabrics (chopped-strand mats) were coated with polyamide 6,6 by interfacial coating and solution dip-coating. Hand lay-up was employed to fabricate polyester-based laminates. Short beam shear tests were performed in order to assess the effect of the coating on the adhesion of the fibre to the matrix. The data show that both coatings have a negative effect on the interlaminar shear strength. Moisture absorption tests were also carried out. Weight gain data versus time of immersion were collected at different immersion temperatures and the water uptake at equilibrium (M ϱ ) and the diffusion coefficient (D) were calculated. An increase in M ϱ and D, as the amount of polyamide coating on the glass fibres increases, was observed. We also observed that many of the diffusion curves, at lower temperatures, exhibit a two-stage sorption (2SS) form. ᭧

This study involves the determination of the mechanical and fracture properties of polyamide 6 reinforced with short glass fibres (35 wt. %) at five different moisture contents (0, 1, 2, 3, and 6 wt. %, respectively). The mechanical characterisation consisted of tensile tests on plane specimens to determine the influence of moisture content on the material's mechanical parameters. The study of fracture properties was carried out by performing single-edge notch bending tests on specimens with the levels of moisture mentioned above in order to obtain the critical stress intensity factor, K Ic . The experimental results showed that the material fracture behaviour cannot be properly described following this methodology; for this reason, a more ambitious scope was established, consisting of determining the J-integral during stable propagation by combining the experimental force vs. displacement curves with the results of a finite element numerical model. The analysis clearly demonstrates the improvement in the material's toughness as humidity increases. The subsequent fractographic study performed through scanning electron microscopy allowed the influence of moisture content on the fracture micro-mechanisms developed during fracture and propagation to be determined.

A series of thermal conductivity measurements for various materials was performed in a large climate chamber. The size of the chamber allowed the preparation of relatively large samples in a controlled thermal environment. Three types of thermal sensors were used: (1) two needle probes; (2) a grid of temperature sensors, evenly distributed inside the sample; (3) two additional thermal probes, which were simplified versions of an instrument originally developed for measuring thermal properties of the ice/dust mixture expected to exist at the surface of a comet nucleus. They consist of a series of individual temperature sensors integrated into a glass fibre rod. Each of these sensors can be operated in an active (heated) or passive (only temperature sensing) mode. The following sample materials were used: fine-grained reddish sand, coarse-grained moist sand, gravels with various grain size distributions from < 1 cm up to about 6 cm, and for comparison and calibration pure water (with convection suppressed by adding agar-agar), compact ice, and compact granite. Of particular interest are the measurements with composite samples, like stones embedded in an agar-agar matrix. We describe the evaluation methods and present the results of the thermal conductivity measurements.

Raman spectroscopy, plasma emission spectroscopy, electron spectroscopy for chemical analysis (ESCA), elemental analysis, solution conductivity and pH, were used to characterise the solutions and the acid, base and silane-treated E-glass fibres. Strong acids and bases induced an ion exchange reaction, which caused large quantities of aluminium and calcium to be leached from the E-glass surface. Samples treated with strong bases were found to have large quantities of sodium on the E-glass fibre surface; this came from the sodium hydroxide used to treat the fibres and from the bulk of the fibre. A cyclic isocyanurate silane, which was only partially soluble in water, was detected on the E-glass surface. A cationic amino-functional silane ester with a long organic chain did not completely hydrolyse in an aqueous solution adjusted to pH=4. The solution concentration, which gave the maximum amount deposited, was different for each silane tested.

Soxhlet extraction has been compared with pressurised and atmospheric microwave-assisted extraction, accelerated solvent extraction and supercritical fluid extraction for the extraction of polycyclic aromatic hydrocarbons (PAHs) from native, contaminated soil. The results indicate that the recovery of PAHs is dependent on the extraction technique. The highest recoveries of individual PAHs were consistently obtained by Soxhlet extraction. For the samples investigated here the preferred technique in terms of recoveries is Soxhlet extraction. © 1997 Elsevier Science B. V.

Carbon fibres are gaining use as reinforcement in glass fibre/polyester composites for increased stiffness as a hybrid composite. The mechanics and chemistry of the carbon fibre-polyester interface should be addressed to achieve an improvement also in fatigue performance and off-axis strength. To make better use of the versatility of unsaturated polyesters in a carbon fibre composite, a set of unsaturated polyester resins have been synthesized with different ratios of maleic anhydride, o-phthalic anhydride and 1,2-propylene glycol as precursors. The effective interfacial strength was determined by micro-Raman spectroscopy of a single-fibre composite tested in tension. The interfacial shear strength with untreated carbon fibres increased with increasing degree of unsaturation of the polyester, which is controlled by the relative amount of maleic anhydride. This can be explained by a contribution of chemical bonding of the double bonds in the polymer to the functional groups of the carbon fibre surface. q

This study proposes the realisation of low-loss fibres in the Ge-Se system. Ge-Se chalcogenide fibres are transparent in the near and middle infrared and show a high non linear refractive index. So, such fibres are of high interest for new optical applications like all optical telecommunication provided that optical losses be sufficiently low. To decrease the optical losses of fibres, several GeSe 4 glasses have been prepared with different chemical and physical purification steps and thorough distillation of selenium under dynamic vacuum. The lowest the optical losses of GeSe 4 fibre are lower than 0.5 dB/m between 1.7 and 7.5 lm except at 4.5 lm where losses are equal to 2.8 dB/m because of Se-H absorption.

Purpose Glutathione S-transferases (GSTs) are intimately involved in combating oxidative stress and in detoxifying xenobiotics. Our objective was to examine possible interactions between polymorphisms in GST genes and plasma vitamin C, tocopherols and carotenoids in 149 reference subjects and 239 subjects occupationally exposed to mineral fibres (asbestos, rock wool, glass fibre), agents that induce oxidative stress. Methods Deletion of GSTM1 and GSTT1, and substitution 105Ile/Val in GSTP1 genes were determined by PCR, antioxidants in plasma were measured by HPLC. Results Tocopherols and carotenoids were affected by age, sex, smoking, occupational exposure to fibres, but not by GST polymorphisms. Vitamin C level was influenced by sex, smoking and occupational exposure. Subjects with deletion of GST had lower vitamin C levels compared with subjects carrying the functional gene variant. Vitamin C levels varied according to GSTM1 polymorphism in the whole group (p \ 0.05), in all reference subjects (p \ 0.05), in the asbestos factory reference group (p \ 0.05), and according to GSTT1 polymorphism in reference group of the rock wool plant (p \ 0.05). Vitamin C levels were approximately 20% lower in subjects with both functionally deficient genes in the whole group (p \ 0.01) and in all non-exposed subjects (p \ 0.05). Conclusions The correspondence of lower vitamin C levels with non-functional GST isoenzymes may indicate a causal connection between two antioxidant defence pathways, also the underlying mechanism is not yet clear. It seems that supplementation by natural antioxidants is particularly important for subjects with unfavourable genetic makeup and in those exposed to oxidative stress.

In this paper a numerical approach of a time-dependent fluid-structure coupling for membrane and thin shell structures with large displacements is presented. The frame algorithm is partitioned, yet fully implicit because of a predictor-corrector scheme being applied to the structural displacements within each time step. In order to reach a high modularity, two powerful codesFone of them highly adapted to flow simulation and the other one to structural dynamicsFrun simultaneously and exchange fluid loads and displacements within each fluidstructure iteration. The finite volume based CFD code is able to compute three-dimensional, incompressible, turbulent flows. The structural simulations are performed using a finite element program including algorithms for geometrically and physically non-linear problems.

In this work, natural fibres (sisal, kenaf, hemp, jute and coir) reinforced polypropylene composites were processed by compression moulding using a film stacking method. The mechanical properties of the different natural fibre composites were tested and compared. A further comparison was made with the corresponding properties of glass mat reinforced polypropylene composites from the open literature. Kenaf, hemp and sisal composites showed comparable tensile strength and modulus results but in impact properties hemp appears to out-perform kenaf. The tensile modulus, impact strength and the ultimate tensile stress of kenaf reinforced polypropylene composites were found to increase with increasing fibre weight fraction. Coir fibre composites displayed the lowest mechanical properties, but their impact strength was higher than that of jute and kenaf composites. In most cases the specific properties of the natural fibre composites were found to compare favourably with those of glass. #

Three techniques of bond strength determination in micromechanical tests-fibre strain profile analysis by means of Raman spectroscopy, "kink" force determination in a traditional pull-out test, and crack length monitoring in a microbond test-were used for investigation of interfacial debonding in epoxy-glass fibre and epoxy-aramid fibre systems. Crack propagation was characterised by local interfacial parameters-critical energy release rate, G ic , and ultimate interfacial shear strength (IFSS), t ult . The comparison of the results showed good agreement both between different techniques and between stress-based and energy-based failure criteria. Sizing of glass fibres caused more pronounced variations in the IFSS than for aramid fibres due to different interfacial failure patterns. The strength of "real" epoxy-glass composites with sized and unsized fibres correlates well with the bond strength determined from the micromechanical tests. ᭧

New helical coupling plasma system for continuous surface treatment and modification (surface processing) of fiber bundles has been developed and tested for glass fibers. The system enables surface processing of single filaments and flat substrates as well. Surface processed glass fibers and their bundles were examined as reinforcements for glass fiber/polyester composite systems. Processing of fibers comprised a surface treatment using argon gas and a surface modification using hexamethyldisiloxane and vinyltriethoxysilane monomers. Interfacial and interlaminar shear strengths of plasma processed glass fiber/polyester systems were compared with those of untreated and commercially sized fibers. q

Powertrain hybridization as well as electrical energy management are imposing new requirements on electrical storage systems in vehicles. This paper characterizes the associated vehicle attributes and, in particular, the various levels of hybrids. New requirements for the electrical storage system are derived, including: shallow-cycle life, high dynamic charge acceptance particularly for regenerative braking and robust service life in sustained partial-state-of-charge usage. Lead/acid, either with liquid or absorptive glass-fibre mat electrolyte, is expected to remain the predominant battery technology for 14 V systems, including micro-hybrids, and with a cost-effective battery monitoring system for demanding applications. Advanced AGM batteries may be considered for mild or even medium hybrids once they have proven robustness under real-world conditions, particularly with respect to cycle life at partial-states-of-charge and dynamic charge acceptance. For the foreseeable future, NiMH and Li-ion are the dominating current and potential battery technologies for higher-functionality HEVs. Li-ion, currently at development and demonstration stages, offers attractive opportunities for improvements in performance and cost. Supercapacitors may be considered for pulse power applications. Aside from cell technologies, attention to the issue of system integration of the battery into the powertrain and vehicle is growing. Opportunities and challenges for potential "battery pack" system suppliers are discussed.

Critical strain energy release rate of glass/epoxy laminates using the virtual crack closure technique for mode I, mode II, mixed-mode I + II and mode III were determined. Mode I, mode II, mode III and mixed-mode I + II fracture toughness were obtained using the double cantilever beam test, the end notch flexure test, the edge crack torsion test and the mixed-mode bending test respectively. Results were analysed through the most widely used criteria to predict delamination propagation under mixed-mode loading: the Power Law and the Benzeggagh and Kenane criteria. Mixed-mode fracture toughness results seem to represent the data with reasonable accuracy.

Composites materials are used in almost all aspects of the industrial and commercial fields in aircraft, ships, common vehicles, etc. Their most attractive properties are the high strength-to-weight ratio. Polymer composites are used because overall properties of the composites are superior to those of the individual polymers. Glass Fiber composites are considered to have potential use as a reinforcing material in epoxy polymer based composites because of their good strength, stiffness etc., The aim of the present work is to investigate the mechanical properties of Glass Fibre Reinforced Epoxy Based Composites. Here, Glass fiber is the fiber reinforcement and epoxy polymer resin as a matrix material. Composites were prepared with longitudinal (Unidirectional) cross (Bidirectional) and chopped glass fiber reinforced with epoxy based polymer. Mechanical test i.e. tensile test was performed on UTM and flexural test was done on flexural testing machine and the results are reported in the conclusion.

Recent regulation IEC 60335-1 ed.4 (2008) was introduced for materials used in electric appliance, establishing new limits in Glow Wire Ignition Temperature (GWIT) performance for materials used for electric connectors. Development of new products with high GWIT is possible, but the main issue is to keep good mechanical properties and processability, as well as tracking resistance (Comparative Tracking Index-CTI). Only a

During the past decades, increasing demand in aircraft industry for high-performance, lightweight structures have stimulated a strong trend towards the development of refined models for fibre-metal laminates (FMLs). Fibre metal laminates are hybrid composite materials built up from interlacing layers of thin metals and fibre reinforced adhesives. The most commercially available fibre metal laminates (FMLs) are ARALL (Aramid Reinforced Aluminium Laminate), based on aramid fibres, GLARE (Glass Reinforced Aluminium Laminate), based on high strength glass fibres and CARALL (Carbon Reinforced Aluminium Laminate), based on carbon fibres. Taking advantage of the hybrid nature from their two key constituents: metals (mostly aluminium) and fibre-reinforced laminate, these composites offer several advantages such as better damage tolerance to fatigue crack growth and impact damage especially for aircraft applications. Metallic layers and fibre reinforced laminate can be bonded by classical techniques, i.e. mechanically and adhesively. Adhesively bonded fibre metal laminates have been shown to be far more fatigue resistant than equivalent mechanically bonded structures.

The aim of the present work is to demonstrate that an efficient all solid electric double layer capacitor (EDLC) may be realised with electrolyte membrane and carbon based electrodes prepared by using a Nafion ionomer solution. Polymer membrane was prepared by a casting method. Electrodes were prepared with two overlapped layers formed of a carbon Á/Nafion layer and a carbon paper substrate. Three different electrolyte separators in capacitor configuration have been tested and compared: (1) a commercial Nafion 115 membrane (N115), (2) a membrane prepared by casting the Nafion 1100 solution (NRG50) and (3) a porous glass fibre matrix impregnated with a 1 M H 2 SO 4 solution (FVH2SO4). The membrane and electrodes assemblies (MEA) had thickness of 0.6 Á/ 0.8 mm and geometric area of 4 cm 2 . The EDLCs characteristics have been studied by conductivity, cyclic voltammetry and DC charge Á/discharge methods. Proton conductivities of 5.7 )/10 (2 and 3.1 )/10 (2 S cm (1 have been measured at room temperature for the N115 and the NRG50, respectively. Specific capacity of 13.2 F g (1 has been obtained by capacitor utilising the cast Nafion membrane. This value is 70% of specific capacity obtained from the capacitor using sulphuric acid and about 140% of that using Nafion 115. #

To determine if semi-rigid synthetic casts provide any measurable advantages compared to rigid synthetic casts. Background. Glass fibre bandages are now commonly applied immediately post-injury to provide rigid immobilisation of the limb, for both weight bearing and non-weight bearing casts. However, composite casts that have inherent flexibility are also available and it is claimed they provide some functionality.

Composites fabricated by VARTM technology with the use of single-ply non-crimp 3D orthogonal woven preforms 3WEAVE Ò find fast growing research interest and industrial applications. It is now well understood and appreciated that this type of advanced composites provides efficient delamination suppression, enhanced damage tolerance, and superior impact, ballistic and blast performance characteristics over 2D fabric laminates. At the same time, this type of composites, having practically straight in-plane fibers, show significantly better in-plane stiffness and strength properties than respective properties of a ''conventional" type 3D interlock weave composites. One primarily important question, which has not been addressed yet, is how the in-plane elastic and strength characteristics of this type of composites compare with respective in-plane properties of ''equivalent" laminates made of 2D woven fabrics. This 2-part paper presents a comprehensive experimental study of the comparison of in-plane tensile properties of two single-ply non-crimp 3D orthogonal weave E-glass fiber composites on one side and a laminate reinforced with four plies of plain weave E-glass fabric on the other. Results obtained from mechanical testing are supplemented by acoustic emission data providing damage initiation thresholds, progressive cracks observation, full-field surface strain mapping and cracks observation on micrographs. The obtained results demonstrate that the studied 3D non-crimp orthogonal woven composites have considerably higher in-plane ultimate failure stresses and strains, as well as damage initiation strain thresholds than their 2D woven laminated composite counterpart. Part 1 presents the description of materials used, experimental techniques applied, principal results and their mutual comparisons for the three tested composites. Part 2 describes in detail the experimentally observed effects and trends with the main focus on the progressive damage: detailed results of AE registration, full-field strain measurements and progressive damage observations, highlighting peculiarities of local damage patterns and explaining the succession of local damage events, which leads to the differences in strength values between 2D and 3D composites.

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.

Moisture absorption and durability in water environment are major concerns for natural fibres as reinforcement in composites. This paper presents a study on the influence of water ageing on mechanical properties and damage events of flax-fibre composites, compared with glass-fibre composites. The effects of the immersion treatment on the tensile characteristics, water absorption and acoustic emission (AE) recording were investigated. The water absorption results for the flax-fibre composites show that the evolution appears to be Fickian and the saturated weight gain is 12 times as high that the glass-fibre composites. Decreasing continuously with increasing water immersion time, the tensile modulus and the failure strain of flax-fibre composites are hardly affected by water ageing whereas only the tensile stress is reduced regarding the glass-fibre composites. AE indicate that matrix-fibres interface weakening is the main damage mechanism induced by water ageing for both composites.

In this work, natural fibres (sisal, kenaf, hemp, jute and coir) reinforced polypropylene composites were processed by compression moulding using a film stacking method. The mechanical properties of the different natural fibre composites were tested and compared. A further comparison was made with the corresponding properties of glass mat reinforced polypropylene composites from the open literature. Kenaf, hemp and sisal composites showed comparable tensile strength and modulus results but in impact properties hemp appears to out-perform kenaf. The tensile modulus, impact strength and the ultimate tensile stress of kenaf reinforced polypropylene composites were found to increase with increasing fibre weight fraction. Coir fibre composites displayed the lowest mechanical properties, but their impact strength was higher than that of jute and kenaf composites. In most cases the specific properties of the natural fibre composites were found to compare favourably with those of glass. #

The paper deals with experimental investigations on reinforcing the adhesive in single lap joints subjected to mechanical loads such as tensile, bending, impact and fatigue. The adhesive used for bonding was an epoxy reinforced with unidirectional and chopped glass fibres as well as micro-glass powder. The adherends were glass reinforced composite laminates. The bonding surfaces were prepared before joining. In the case of unidirectional fibres in the adhesive region, the fibre orientations considered were 0°, 45° and 90°. The volume fraction of fibres in the adhesive layer in all the cases was 30%. The volume fractions of micro-glass powder were 20%, 30% and 40%. The tensile, bending, impact and fatigue tests on the prepared specimens were conducted according to ASTM standards. The results show that except the 90° unidirectional orientation, reinforcing the adhesive with glass fibres or powder increases the joint strength. The use of volume fraction of 30% of micro-glass powder gave the best performance in the above loading conditions. The fatigue life increased by 125%, the ultimate joint strength in tension increased by 72%, the bending ultimate joint strength increased by 112% and the impact joint strength increased by 63%. The microstructure of the debonded area was examined and three modes of failure could be observed namely cohesive failure, light fibre-tear failure and thin layer cohesive failure.

Composites fabricated by VARTM technology with the use of single-ply non-crimp 3D orthogonal woven preforms 3WEAVE Ò find fast growing research interest and industrial applications. It is now well understood and appreciated that this type of advanced composites provides efficient delamination suppression, enhanced damage tolerance, and superior impact, ballistic and blast performance characteristics over 2D fabric laminates. At the same time, this type of composites, having practically straight in-plane fibers, show significantly better in-plane stiffness and strength properties than respective properties of a ''conventional" type 3D interlock weave composites. One primarily important question, which has not been addressed yet, is how the in-plane elastic and strength characteristics of this type of composites compare with respective in-plane properties of ''equivalent" laminates made of 2D woven fabrics. This 2-part paper presents a comprehensive experimental study of the comparison of in-plane tensile properties of two single-ply non-crimp 3D orthogonal weave E-glass fiber composites on one side and a laminate reinforced with four plies of plain weave E-glass fabric on the other. Results obtained from mechanical testing are supplemented by acoustic emission data providing damage initiation thresholds, progressive cracks observation, full-field surface strain mapping and cracks observation on micrographs. The obtained results demonstrate that the studied 3D non-crimp orthogonal woven composites have considerably higher in-plane ultimate failure stresses and strains, as well as damage initiation strain thresholds than their 2D woven laminated composite counterpart. Part 1 presents the description of materials used, experimental techniques applied, principal results and their mutual comparisons for the three tested composites. Part 2 describes in detail the experimentally observed effects and trends with the main focus on the progressive damage: detailed results of AE registration, full-field strain measurements and progressive damage observations, highlighting peculiarities of local damage patterns and explaining the succession of local damage events, which leads to the differences in strength values between 2D and 3D composites.

The mechanical properties of glass ionomer cements used in restorative dentistry reinforced by chopped glass fibres were investigated. Reactive glass fibres with a composition in the system SiO 2 -Al 2 O 3 -CaF 2 -Na 3 AlF 6 and a thickness of 26 mm were drawn by a bushing process. The manufacturing parameters were optimized with respect to maximum strength of the glass fibre reinforced ionomer cements. Powder to liquid ratio, pre-treatment of the glass, grain size distribution and fibre volume fraction were varied. Glass fibre and cement were characterized by X-ray diffraction, transmission electron microscopy and energy dispersive spectroscopy techniques, respectively. The highest flexural strength of the reinforced cement (15.6 MPa) was found by compounding 20 vol% reactive fibres and extending the initial dry gelation period up to 30 min. Microscopic examination of the fractured cements indicated a distinct reactive layer at the fibre surface. A pronounced fibre pull out mode gives rise to an additional work-of-fracture contributed by pulling the fibres out of the fracture surface. r

A new generation of composite pressure vessels for large scale market applications has been studied in this work. The vessels consist on a thermoplastic liner wrapped with a filament winding glass fibre reinforced polymer matrix structure. A high density polyethylene (HDPE) was selected as liner and a thermosetting resin was used as matrices in the glass reinforced filament wound laminate. The Abaqus 6.5.1 FEM package were used to predict the mechanical behaviour of pressure vessels with capacity of approximately of 0,068 m 3 (68 l) for a 0.6 MPa (6 bar) pressure service condition according to the requirements of the prEN 13923 standard, namely, the minimum internal burst pressure. The Tsai-Wu and Von Mises criteria were used to predict composite laminate and thermoplastic liner failures, respectively, considering the elasto-plastic behaviour of the HDPE liner and the laminae properties deducted from micromechanical models for composite laminates. Finally, prototype pressure vessels were produced in the defined conditions to be submitted to pressure tests. The comparison between the FEM simulations and experimental results are discussed in the present paper.

Two woven fabric laminates, one based on basalt fibres, the other on E-glass fibres, as a reinforcement for vinylester matrix, were compared in terms of their post-impact performance. With this aim, first the non-impacted specimens were subjected to interlaminar shear stress and flexural tests, then flexural tests were repeated on laminates impacted using a falling weight tower at three impact energies (7.5, 15 and 22.5 J). Tests were monitored using acoustic emission analysis of signal distribution with load and with distance from the impact point. The results show that the materials have a similar damage tolerance to impact and also their post-impact residual properties after impact do not differ much, with a slight superiority for basalt fibre reinforced laminates. The principal difference is represented by the presence of a more extended delamination area on E-glass fibre reinforced laminates than on basalt fibre reinforced ones.

The fracture of adhesive joints between two glass-fibre laminates was studied by testing double cantilever beam test specimens loaded by uneven bending moments. A large-scale fracture process zone, consisting of a crack tip and a fibre bridging zone, developed. The mixed mode fracture resistance increased with increasing crack length, eventually reaching a steady-state level (R-curve behaviour). The steady-state fracture resistance level increased with increasing amount of tangential crack opening displacement. Cohesive laws, obtained from fracture resistance data, were used for prediction the load carrying capacity of 2-m long ''medium size" adhesive joint specimens subjected to four point flexure. Medium size specimens were manufactured and tested. A good agreement was found between the predicted and measured strength values of the medium-size specimens. Thus, the scaling from small specimens to medium-size specimens was successfully achieved.

Although commercial kits are available for automated DNA extraction, 'artisanal' protocols are not. In this study, we present a silica-based method that is sensitive, inexpensive and compliant with automation. The effectiveness of this protocol has now been tested on more than 5000 animal specimens with highly positive results.

In this work, the effect of a biaxial preload in the behaviour of glass/polyester woven-laminate plates subjected to high-velocity transversal impact was studied. For this, an analytic model based on energy considerations that include the presence of an in-plane preload was used. The results of the analytic model for the biaxial preload state were compared with those found for a non-preload plate, the difference between them being minimal for the pre-stressed level reached in the tests (31% of the static UTS).

Fibre Metal Laminates with layers of aluminium alloy and high strength glass fibre composite have been reported to possess excellent impact properties and be suitable for aircraft parts likely to be subjected to impacts such as runway debris or bird strikes. In a collaborative research project, aircraft wing leading edge structures with a glass-based FML skin have been designed, built, and subjected to bird strike tests that have been modelled with finite element analysis. In this second part of a two-part paper, a finite element model is developed for simulating the bird strike tests, using Smooth Particle Hydrodynamics (SPH) for modelling the bird and the material model developed in Part 1 of the paper for modelling the leading edge skin. The bird parameters are obtained from a system identification analysis of strikes on flat plates. Pre-test simulations correctly predicted that the bird did not penetrate the leading edge skin, and correctly forecast that one FML lay-up would deform more than the other. Post test simulations included a model of the structure supporting the test article, and the predicted loads transferred to the supporting structure were in good agreement with the experimental values. The SPH bird model showed no signs of instability and correctly modelled the break-up of the bird into particles. The rivets connecting the skin to the ribs were found to have a profound effect on the performance of the structure.

We investigate high-modulus degradable materials intended to replace metals in biomedical applications. These are typically composites comprising a polylactide (PLA) matrix reinforced with phosphate glass fibres, which provide reinforcement similar to E-glass but are entirely degradable in water to produce, principally, calcium phosphate. We have made composites using a variety of fibre architectures, from non-woven random mats to unidirectional fibre tapes. Flexural properties in the region of 30 GPa modulus and 350 MPa strength have been achieved-directly comparable to quoted values for human cortical bone. In collaboration with other groups we have begun to consider the development of foamed systems with structures mimicking cancellous bone and this has shown significant promise. The fibres in these foamed structures provide improved creep resistance and reinforcement of the pore walls. To date the materials have exhibited excellent cellular responses in vitro and further studies are due to include consideration of the surface character of the materials and the influence of this on cell interaction, both with the composites and the glass fibres themselves, which show promise as a standalone porous scaffold.

Selection of materials, as an area of design research, has been under considerable interest over the years. Materials selection is one of the most important activities in the product development process. Inappropriate decision of materials can cause the product to be reproduced or remanufactured. To avoid this circumstance, one of the useful tools that can be employed in determining the most appropriate material is analytical hierarchy process (AHP). To illustrate the application of AHP, six different types of composite materials were considered. The most appropriate one for suitability of use in manufacturing automotive bumper beam was determined by considering eight main selection factors and 12 sub-factors. The AHP analysis reveals that the glass fibre epoxy is the most appropriate material because it has the highest value (25.7%, mass fraction) compared with other materials. The final material is obtained by performing six different scenarios of the sensitivity analysis. It is proved that glass fibre epoxy is the most optimum decision.

ÐThe deformation and fracture behaviour of glass ®bre±epoxy braided circular tubes is examined experimentally and theoretically for the loading cases of compression, torsion, and combined tension±torsion and compression±torsion. Failure maps are produced for compression and for torsion to summarise the eect of braid microstructure upon failure mode and upon the mechanical properties of the braid, including yield strength, modulus, strain to failure and energy absorption. In compression, two competing mechanisms are observed: diamond shaped buckling of the tube and ®bre microbuckling. In torsion and in combined compression±torsion, the tubes fail by ®bre microbuckling. The initiation and propagation stresses for diamond shaped buckling, and the critical stress for ®bre microbuckling are successfully predicted using simple micromechanical models. Drawing upon the available experimental data, yield surfaces are constructed for in-plane loading of the braid, and a comprehensive mechanism map is constructed to illustrate the dependence of failure mode upon braid geometry and loading direction.

The pattern of fibre orientation in injection moulded strips of glass fibre reinforced polypropylene has been studied using the technique of contact micro-radiography. It has been found that the fibre orientation in the core of the mouldings is very dependent on injection speed. High injection speed gives alignment of fibres transverse to the flow direction, while for very low speeds the fibres align parallel to the flow. The associated changes in topography of the mouldings have been studied using scanning electron microscopy. The rheological properties of both glass fibre-filled and unfilled polypropylene have been studied in a capillary rheometer. At low shear rates, the fibres cause a significant increase in viscosity, but at the shear rates likely to be encountered in injection moulding, the filled and unfilled melts have very similar viscosities. The rheological data can be used to interpret the pattern of fibre orientation in the mouldings.

The behavior of reinforced concrete panels, or slabs, retrofitted with glass fiber reinforced polymer (GFRP) composite, and subjected to blast load is investigated. Eight 1000 · 1000 · 70 mm panels were made of 40 MPa concrete and reinforced with top and bottom steel meshes. Five of the panels were used as control while the remaining four were retrofitted with adhesively bonded 500 mm wide GFRP laminate strips on both faces, one in each direction parallel to the panel edges. The panels were subjected to blast loads generated by the detonation of either 22.4 kg or 33.4 kg ANFO explosive charge located at a 3-m standoff. Blast wave characteristics, including incident and reflected pressures and impulses, as well as panel central deflection and strain in steel and on concrete/FRP surfaces were measured. The post-blast damage and mode of failure of each panel was observed, and those panels that were not completely damaged by the blast were subsequently statically tested to find their residual strength. It was determined that overall the GFRP retrofitted panels performed better than the companion control panels while one retrofitted panel experienced severe damage and could not be tested statically after the blast. The latter finding is consistent with previous reports which have shown that at relatively close range the blast pressure due to nominally similar charges and standoff distance can vary significantly, thus producing different levels of damage.

In the current paper, The compressive strength and failure mechanisms are investigated for hybrid composites. Static uniaxial compressive tests are performed on notched specimens made from two layers of carbon, glass, and Kevlar fibres and epoxy resin combined to give six different stacking hybrid composite materials. Cohesive zone model is applied to estimate the open-hole compression (OHC) strength.

An amperometric glucose biosensor strip based on a three electrodes (counter, reference and working) planar configuration was fabricated using thick film technology. Glucose oxidase (GOD) was immobilized in the bulk of a graphite-epoxy composite paste. This paste was used to screen-print the working electrode on a glass fibre board. The integration on the same support of pseudo-reference electrode was obtained by screen printing a commercial silver-epoxy paste, and subsequent electrochemical chlorinization in KCl 1 M at + 1 V (SCE). Finally, the counter electrode was integrated using the same technique by depositing a graphite-epoxy composite paste, taking into account the counter/working electrode area ratio. Response characteristics of a glucose biosensor strip based on this transducer are similar to those of previously reported one electrode configuration glucose biosensor constructed using the same biocomposite material [Galán-Vidal and Muñ oz, Sens. Actuators B 45 (1997) 55-62].

This Part 2 paper presents results of comparative experimental study of progressive damage in 2D and 3D woven glass/epoxy composites under in-plane tensile loading. As Part 1, this Part 2 work is focused on the comparison of in-plane tensile properties of two non-crimp single-ply 3D orthogonal weave E-glass fibre composites on one side and a laminate reinforced with four plies of E-glass plain weave on the other. The damage investigation methodology combines mechanical testing with acoustic emission registration (that provides damage initiation thresholds), progressive cracks observation on transparent samples, full-field surface strain mapping and cracks observation on micrographs, altogether enabling for a thorough characterisation of the local micro- and meso-damage modes of the studied composites. The obtained results demonstrate that the non-crimp 3D orthogonal woven composites have significantly higher in-plane strengths, failure strains and damage initiation thresholds than their 2D woven laminated counterpart. The growth of transverse cracks in the yarns of 3D composites is delayed, and they are less prone to a yarn–matrix interfacial crack formation and propagation. Delaminations developing between the plies of plain weave fabric in the laminate at certain load level never appear in the 3D woven single-ply composites.