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Recently, glass fiber reinforced polypropylene is commonly used in scientific and industrial applications such as marine, aerospace, automotive, and construction industries among other materials because of their low cost, lightweight, easy processing, and high reliability. For those promising characteristics, researches have been undertaken for understanding the thermal and mechanical behaviors of polypropylene. The main objective of this study is to investigate the mechanical properties of polypropylene (PP) and glass fiber reinforced polypropylene (GFPP) pipes, which are used in water distribution networks and compressed air systems. Tensile tests were performed at different cross-head speeds at room temperature while, flexural tests were conducted at different cross-head speeds with five distinct temperatures 23, 35, 50, 70, and 90 °C. The experimental results show that both materials are sensitive to cross-head speed, temperature, and holding time. Additionally, the percentage of elongation at break and toughness of GFPP are lower than that of PP. However, the elastic modulus and yield stress of GFPP are higher than that of PP at the same cross-head speed. On the other hand, the bending energy and the dissipated energy of GFPP are higher than that of PP under all cross-head speeds and testing temperatures. PP gains 20.4% and GFPP gains 15.2% bending energy with raising cross-head speed from 5 to 50 mm/min. Also, a decrease in flexural modulus for both materials occurs with raising temperature from 23 to 50 °C.

The aim of this study is to investigate the influence of different glass fibers made of commercial silicate, borosilicate, and laboratory-made iron–phosphate compositions, on the preparation of polylactic acid (PLA) composites and their structural and physical properties. The thermal, structural, and electrical properties of prepared PLA–glass fiber composites were studied using differential scanning calorimetry, X-ray diffraction, microscopy, and impedance spectroscopy. The structural as well as morphological, thermal, and electrical properties of all PLA–glass composites were found to be very similar and independent of the composition and aspect ratio of glass fibers. All types of glass fibers improve mechanical properties, increase thermal stability, and decrease the electrical conductivity of PLA, thereby producing mechanical strong electrically insulating composite material with potential in various applications.

In this study, the effect of adding nanosize additive to glass fiber reinforced composite plates on mechanical properties and surface milling was investigated. In the light of the investigations, with the addition of MWCNTs additive in the composite production, the strength of the material has been changed and the more durable composite materials have been obtained. Slots were opened with different cutting speed and feed rate parameters to the composite layers. Surface roughness of the composite layers and slot size were examined and also abrasions of cutting tools used in cutting process were determined. It was observed that the addition of nanoparticles to the laminated glass fiber composite materials played an effective role in the strength of the material and caused cutting tool wear.

The main goal of this paper is the evaluation of the properties reversibility of glass fiber reinforced polymers (GFRPs) under discontinuous exposure to aggressive environmental conditions, typical of marine applications. To this aim, the GFRP manufactured through vacuum infusion process has been initially aged in humid conditions (i.e., exposure to salt-fog at 35 ◦C) for 15 and 30 days and then stored under controlled dry conditions (i.e., 50% R.H. and 23 ◦C) for times varying between 0 and 21 days. In order to evaluate the recover capability of this material, its water uptake has been monitored along the quasi-static flexural properties during the entire humid/dry cycle. Moreover, both 3D optical and scanning electron microscopes (SEM) have been used to analyze the morphology of fractured samples at different humid and dry times, thus correlating the properties evolution of the composite with its morphology. The main outcome of the present paper is an evident performances recovery shown by the investigated composite during the drying phase. Indeed, despite its flexural strength and modulus were reduced by about 20% and 10% after 30 days of salt-fog exposition, the GFRP composite evidenced a complete recovery of its initial mechanical performances after long drying times (i.e., 21 days). These findings clearly indicate that although some degradation phenomena occurred during the humid phase, their effects on both strength and stiffness of the investigated composite have proven to be mainly reversible.

To strengthen the mechanical properties of a fiber-reinforced plastic without deteriorating its toughness caused by adding nanomaterial, multiscale hybrid composites (MHC) composed of polyamide 6 (PA6), woven glass fibers (WGFs), nanoclay, and various additives were fabricated and characterized. A surfactant was used to improve the dispersion of the nanoclay in the composite, and a compatibilizer and toughening agent were added to enhance the interfacial interactions between the nanoclay and PA6 and the toughness of the MHC, respectively. In addition, the WGFs were pretreated with atmospheric-pressure air plasma to enhance the interfacial bonding between the WGF and the mixture composed of PA6/nanoclay/compatibilizer/toughening agent, which constitutes the matrix. The optimal composition of the PA6 mixture, optimal content of the nanoclay, and optimal conditions of the plasma pretreatment of the WGF surface were experimentally determined. A suitable manufacturing process was employed using a material composition that maximizes the mechanical properties of the MHC by mitigating the toughness deterioration owing to nanoclay addition. An appropriate quantity of the nanoclay increased the tensile properties as well as the elongation at the break of the MHC because the toughening agent prevented the reduction in the degree of elongation caused by increasing the clay content to a certain extent. Moreover, the plasma treatment of the WGF enhanced the flexural properties and impact resistance of the MHC. Therefore, not only the tensile strength, modulus, and elongation at the break of the PA6 nanocomposite, which constitutes the matrix of the MHC, increased up to 39.83, 40.91, and 194.26%, respectively, but also the flexural strength and modulus, absorbed impact energy, and penetration limit of the MHC increased by 20.2, 26.8, 83.7, and 100.0%, respectively.

Given the time-consuming and complex nature associated with the aging of composites, a novel fabric pre-aging method was developed and evaluated for static and fatigue testing. It allows for investigating sizing and interphase-related aging effects. This fast method is independent of the diffusion processes and the composites’ thickness. Moreover, the new methodology offers enhanced analysis of the sizing, interphase, and fiber-related degradation of composites without aging them by conventional accelerated procedures or under severe maritime environments. For validation purposes, fiber bundle, longitudinal, and transverse tensile tests were performed with five different glass fiber inputs. Significant differences in the durability of composites were found for pre-aging and classical aging, respectively. The impacts of degradation of the single constituents on the fatigue life are identified by cyclic testing of untreated, pre-aged, and wet-aged composites. Here, it is evident that the interphase strength is likewise essential for the tension-tension fatigue performance of unidirectional composites, as is the fiber strength itself. In summary, the presented method provides industry and academia with an additional opportunity to examine the durability of different fibers, sizings, and composites for design purposes following a reasonable methodology. Given the time-consuming and complex nature associated with the aging of composites, a novel fabric pre-aging method was developed and evaluated for static and fatigue testing. It allows for investigating sizing and interphase-related aging effects. This fast method is independent of the diffusion processes and the composites’ thickness. Moreover, the new methodology offers enhanced analysis of the sizing, interphase, and fiber-related degradation of composites without aging them by conventional accelerated procedures or under severe maritime environments. For validation purposes, fiber bundle, longitudinal, and transverse tensile tests were performed with five different glass fiber inputs. Significant differences in the durability of composites were found for pre-aging and classical aging, respectively. The impacts of degradation of the single constituents on the fatigue life are identified by cyclic testing of untreated, pre-aged, and wet-aged composites. Here, it is evident that the interphase strength is likewise essential for the tension-tension fatigue performance of unidirectional composites, as is the fiber strength itself. In summary, the presented method provides industry and academia with an additional opportunity to examine the durability of different fibers, sizings, and composites for design purposes following a reasonable methodology.

Hybrid composite samples with different carbon and glass fiber layers arrangement were produced by resin transfer molding (RTM) in an attempt to disclose the effects of low temperature on their flexural and low velocity impact behavior. Flexural tests were carried out at T = −50°C and the failure modes were examined, while impact tests, always at T = −50°C, were performed at penetration and at indentation in the range from 10 J to 30 J. The damage extension was accurately evaluated by ultrasonic non-destructive testing. The results were then compared with the room temperature ones obtained in a previous paper to highlight the influence of the temperature. The compression after impact tests were carried out at room temperature for samples previously impacted at both room and low temperature to assess the damage tolerance of the different hybrid configurations. Stacking sequence was found to govern both the flexural and impact behavior of laminates. At low temperature, the flexural strength and modulus values improved over the corresponding room temperature values irrespective of the stacking sequence, while an easier damage propagation and less residual strength were detected in dynamic loading.

This paper experimentally investigates the effect of steel and glass fibers on the engineering properties of concrete. To achieve this, 0.3%, 0.6%, and 0.9% by volume fraction of steel and glass fibers are added in concrete mixtures with water-to-cement (W/C) ratios 0.35 and 0.45. For each ratio of water to cement, 21 cubic samples for compressive strength tests, 14 cylindrical samples for tension strength tests, and also 14 prismatic samples for three-point flexural strength tests were prepared. The experimental results show that adding 0.3% to 0.9% % steel fibers for concrete increases simultaneously the compressive, tension, and also flexural strengths in comparison with plain concrete. Adding glass fibers only between 0.3% to 0.6% increases the compressive strength. The results reveal that the best range for reinforcing concrete with steel fiber is 0.3% to 0.9 % and glass fiber is 0.3% to 0.6 % by volume fraction of fiber to improve the engineering strengths concrete. As a rule of thumb, the tension and flexural strengths of concrete could be explained as 8% and 13% of the compressive strength, respectively.

In this paper, compression, flexural, tensile and abrasion tests are instituted by the addition of Bacillus megaterium MTCC with glass and steel fibers. The fundamental goal regarding this examination assignment is by segregate than apprehend calcite encouraging microscopic organisms yet in conformity with appearing at the reasonableness over these microorganisms because of utilizes among cement in conformity with enhancing its multiplication yet strength. Microorganisms in imitation of remain fused of cement duly after remaining soluble inferior proof by undergoing the high pH on cement and endospore-shaping after standing up to the mechanical anxieties actuated into cement during blending. They must show excessive urease work in conformity with inspiring calcium carbonate as calcite. Bacterial traces had been separated beyond soluble base exams on an embodied manufacturing range yet have been tried for urease movement, the dynamic in conformity with body endospores or precipitation over calcium carbonate. Considering its outcomes, she has been identified so Bacillus megaterium BSKAU, Bacillus licheniformis BSKNAU or Bacillus flexus BSKNAU. The effects have been contrasted Bacillus megaterium yet MTCC 1684 obtained from Microbial Type Culture Collection or bio life LTD, Hyderabad, India. In that trial with the aid of utilizing Bacillus megaterium MTCC1964 (105 cells/ml over blending water) or calcium lactate (5 g/lit) is utilized. The metal filaments 0 %, 0.5 %, 1.0 %, or 1.5 % yet glass strands 0 %, 0.5 %, 1.0 %, 1.5 % and 2.0 % added in accordance with the sure and reckon the stress esteems because 7, 14 and 28 days. In this effect, we watched high-pressure multiplication within glass filaments at 1% than steel strands at 1.5 %. These stage regarding glass strands then steel strands added according to the bacterial strong at to that amount factor discern the strain exorcism because blocks, pliancy because court of justice yet flexural attribute because bars at 7, 14, 28, 60 years old days. we either count the UPV take a look at for shapes and cantrobro take a look at because courthouse at 28 days historic and 60 days. SEM trial is done after discovering the propinquity concerning caco3 among Bacterial cement.

WOS: 000519806700073, In this study, composites composed of glass fiber reinforced-epoxy laminates interleaved with electrospun polyvinylchloride (PVC) nano-fibres were designed for radar absorption investigations. The laminated composites which were produced in special molds were obtained by placing woven glass fibers between each of PVC nanofiber mats, and the composites were produced in three different forms as pure, multi-walled carbon nanotubes doped and graphene doped. The morphologies of the PVC nanofiber mats were analyzed by scanning electron microscope. The radar absorption efficiencies of the composites in the individual and different combinations were measured in the 3-8 GHz frequency band. Experimental results show that the produced graphene-added composite material has improvable microwave absorption effect at several points in 3-8 GHz band to provide excellent absorption in future studies. The graphene doped structure was found to have a certain absorption characteristic up to 33.82% at a constant frequency. Besides, various strong absorption frequency points have been obtained in the related frequency range. The cascaded graphene doped composite layers can provide broadband absorption for stealth technology.

Increasing demand for energy-efficient means of transport has steadily intensified the trend towards lightweight components. Thermoplastic glass fiber composites (organo sheets) play a major role in the production of functional automotive components. Organo sheets are cut, shaped and functionalized by injection molding to produce hybrid components, such as those used in car door modules. The cutting process produces a considerable amount of production waste, which has thus far been thermally recycled. This study develops a closed mechanical recycling process and analyzes the different steps of the process. The offcuts were shredded using two shredding methods and implemented directly in the injection-molding process. Using tensile tests and impact bending tests, the material properties of the recycled materials were compared with the virgin material. In addition, fiber length degradation via the injection-molding process and the influence of the waterjet-cutting process on the mechanical properties are investigated. Recycled offcuts are both comparable to new material in terms of mechanical properties and usability, and are also economically and ecologically advantageous. Recycling polypropylene waste with glass fiber reinforcement in a closed loop is an effective way to reduce industrial waste in a sustainable and economical production process.

In this study, mechanical testing of glass bead (GB), glass fiber (GF), and hybrid (GB/GF) composites was carried out. Following that, drilling tests were undertaken on glass bead/fiber-reinforced hybrid Polyamide 66 (PA66) polymer composites. The purpose of this study is to determine the mechanical properties of the cutting elements and the effect of cutting parameters (spindle speed and feed rate) and reinforcement ratios on thrust force and surface roughness (Ra). The contribution of the cutting parameters to the investigated outcomes was determined using statistical analysis. Optical microscopy and scanning electron microscopy (SEM) was used to inspect the hole quality and damage mechanisms. The results revealed that the feed rate was the most contributing factor to thrust force (96.94%) and surface roughness (63.59%). Furthermore, in comparison to other hybrid composites, the lowest Ra value was obtained as 0.95 µm in samples containing 30% GB, while the Ra value was 1.04 µm in samples containing 10% GF + 20% GB. Polymer PA reinforced with 30% GF had the highest strength, modulus of elasticity, impact strength, and hardness. © 2022 by the authors. Licensee MDPI, Basel, Switzerland. Karabük Üniversitesi: FDT-2020-2340 Funding: This research was funded by Karabük University, grant number FDT-2020-2340.

In recent years there has been growing interest in developing recycling technologies for composites manufacturing scrap, process waste and end-of-life parts. The focus of this work was to establish processing routes and mechanical property bounds for glass-polypropylene (PP-GF) scrap from the production of parts for truck trailers, automobiles, and rail cars. This study considered PP-GF scrap and demonstrated extrusion-compression molding (ECM) as a viable route for the closed-loop manufacture of composite parts. The results were promising in terms of the strength and modulus retention of the PP-GF recyclate. The tensile strength and modulus was the highest for 50% and 66% recycled content, compared with 100% and 83% recycle content. The flexural strength and modulus of the 100% and 83% recycled compositions was higher than the 66% and 50% recycled content, respectively. The impact energy absorption of the PP-GF recyclate at at all fiber loadings was superior in absorbing energy compared with the incumbent (benchmark) plywood. This work is useful to designers seeking to incorporate recycled materials in their products.

Background Enormous improvements in dental materials’ manufacturing for the aim of producing durable dental materials without compromising the aesthetic properties were developed. One of the approaches that fulfill this aim is the use of reinforcing glass fibers as fillers into dental materials, typically resin polymers, in order to obtain glass fiber-reinforced composites. Glass fiber-reinforced composite offered many advantages to the dental materials though some limitations were recorded in many literature. Methods In this review, a study of the glass fibers’ types, factors affecting the properties and the properties of glass fibers reinforced materials was carried out; in addition, research papers that experimentally studied their applications in dentistry were presented. Conclusion The success of glass fibers reinforced composites in dentistry depends on glass fibers’ composition, orientation, distribution, amount, length and adhesion; these factors once employed according to the required clinical situation would provide the essential reinforcement to the dental restorations and appliances.

This work sheds light on the first steps towards using glass fiber waste for semi-structural applications. This work aims to improve the properties of random flax fiber composites by incorporating waste glass fibers (WGF) obtained from the fiber production line. The waste glass fibers were incorporated as a core structure between the flax layers to form a hybrid composite. Two routes of manufacturing viz. vacuum infusion and autoclave were used to identify the optimum route to incorporate the WGF in flax fiber composites. The quality of composites was investigated in terms of residual void content and thickness uniformity. Residual void content was identified to be directly proportional to the WGF content in the composites. With the increase in WGF content, the flexural and impact properties were increased by 47% and 117%, respectively, indicating a positive hybridization effect. Furthermore, a global warming potential indicator was identified to be small, indicating the eco-friendliness of these composites.

This manuscript version is made available under the CC-BY-NC-ND 4.0 license: http://creativecommons.org/licenses/by-nc-nd/4.0/ which permits use, distribution and reproduction in any medium, provided the original work is properly cited. This author accepted manuscript is made available following 24 month embargo from date of publication (October 2018) in accordance with the publisher’s archiving policy, Interfacial behavior greatly affects the bulk mechanical performance of fiber reinforced polymer laminates. In this study, polydopamine modified glass fiber was used to fabricate short glass fiber reinforced polymer (GFRP) laminates. The interactions between glass fiber and polydopamine were studied experimentally and theoretically by X-ray photoelectron spectroscopy (XPS) and density functional calculation respectively. Theoretical study clearly demonstrated that electronic interactions existed between polydopamine and glass fiber, indicating the hydrogen bonds/chemical interactions between them that were also demonstrated by XPS results. The enhanced interfacial interaction significantly benefited GFRP laminates, as demonstrated by various mechanical characterizations such as single fiber pull-out and Mode I interlaminar fracture toughness tests. Combining the theoretical and experimental studies indicated that polydopamine modification of glass fiber could be an easy and effective way to significantly improve the interfacial interactions between glass fiber and matrix and enhance the mechanical properties of GFRP laminates., H. Zhang and Y Ma are grateful for the support of the China Scholarship Council with the visiting scholar program to Flinders University, Australia. This research was partially supported by Longshan Academic Talent Research Supporting Program of SWUST, China (Grant No.: 17LZX411) and the East Lake Scholars Sponsorship Program of WHSU, China.

Glass fibers are often used as reinforcing fibers in reinforced polymers. Composites reinforced with glass fibers (GFRP) stand out with excellent mechanical and physical properties applicable to industrial practice. Machining these composites requires the correct choice of tools and cutting conditions so that the machined surface shows good properties, there is no fiber delamination, thermal stress on the workpiece and the tool, or excessive tool wear. The study was devoted to circumferential milling of fabric-bonded GFRP plates, in which attention was paid to the influence of the abrasive effect of glass fibers on wear and tool life. Attention was also paid to surface roughness after machining, material delamination, and forces during machining were measured. Three end mills of the same diameter with different coatings, number of teeth, and geometry were selected for the study. This choice of tools was intended to achieve various accompanying and subsequent phenomena that were investigated. Milling was performed on a CNC milling center under preselected cutting conditions. The paper summarizes information on fiber delamination and machined laminate damage after milling, tool wear, and surface roughness parameters as a function of tool wear. This paper provides an opportunity for researchers to increase their knowledge of specific aspects of milling GFRP composites, whether with a tool specifically designed for this or not.

The application of glass fiber reinforced composites has grown rapidly due to their high strength-to-weight ratio, low cost, and chemical resistance. However, the increasing demand for fiber reinforced composites results in the generation of more composite wastes. Mechanical recycling is a cost-effective and environmentally-friendly recycling method, but the loss in the quality of recycled glass or carbon fiber composite hinders the wide-spread use of this recycling method. It is important to develop novel composite materials with higher recyclability. Thermotropic liquid crystalline polymers (TLCPs) are high-performance engineering thermoplastics, which have comparable mechanical performance to that of glass fiber. The TLCP reinforced composites, called in situ composites, can form the reinforcing TLCP fibrils during processing avoiding the fiber breakage problem. The first part of this dissertation is to study the influence of mechanical recycling on the properties of injection molded TLCP and glass fiber (GF) reinforced polypropylene (PP). The processing temperature of the injection molding process was optimized using a differential scanning calorimeter (DSC) and a rheometer to minimize the thermal degradation of PP. The TLCP and GF reinforced PP materials were mechanically recycled up to three times by repeated injection molding and grinding. The mechanical recycling had almost no influence on the mechanical, thermal, and thermo-mechanical properties of TLCP/PP because of the regeneration of TLCP fibrils during the mold filling process. On the other hand, glass fiber/PP composites decreased 30% in tensile strength and 5% in tensile modulus after three reprocessing cycles. The micro-mechanical modeling demonstrated the deterioration in mechanical properties of GF/PP was mainly attributed to the fiber breakage that occurred during compounding and grinding. The second part of this dissertation is concerned with the development of recyclable and light weight hybrid composites through the use of TLCP and glass fiber. Rheological tests were used to determine the optimal processing temperature of the injection molding process. At this processing temperature, the thermal degradation of matrix material was mitigated and the processability of the hybrid composite was improved. The best formulation of TLCP and glass fiber in the composite was determined giving rise to the generation of a recyclable hybrid composite with low melt viscosity, low mechanical anisotropy, and improved mechanical properties. Finally, TLCP reinforced polyamide composites were utilized in an additive manufacturing application. The method of selecting the processing temperature to blend TLCP and polyamide in the dual extrusion process was devised using rheological analyses to take advantage of the supercooling behavior of TLCP and minimize the thermal degradation of the matrix polymer. The composite filament prepared by dual extrusion was printed and the printing temperature of the composite filament that led to the highest mechanical properties was determined. Although the tensile strength of the TLCP composite was lower than the glass fiber or carbon fiber composites, the tensile modulus of 3D printed 60 wt% TLCP reinforced polyamide was comparable to traditional glass or carbon fiber reinforced composites in 3D printing. Doctor of Philosophy The large demand for high performance and light weight composite materials in various industries (e.g., automotive, aerospace, and construction) has resulted in accumulation of composite wastes in the environment. Reuse and recycling of fiber reinforced composites are beneficial from the environmental and economical point of view. However, mechanical recycling deteriorates the quality of traditional fiber reinforced composite (e.g., glass fiber and carbon fiber). There is a need to develop novel composites with greater recyclability and high-performance. Thermotropic liquid crystalline polymers (TLCP) are attractive high performance materials because of their excellent mechanical properties and light weight. The goal of this work is to generate recyclable thermotropic liquid crystalline polymer (TLCP) reinforced composites for use in injection molding and 3D printing. In the first part of this work, a novel recyclable TLCP reinforced composite was generated using the grinding and injection molding. Recycled TLCP composites were as strong as the virgin TLCP composites, and the mechanical properties of TLCP composites were found to be competitive with the glass fiber reinforced counterparts. In the second part, a hybrid TLCP and glass fiber reinforced composite with great recyclability and excellent processability was developed. The processing conditions of injection molding were optimized by rheological tests to mitigate fiber breakage and improve the processability. Finally, a high performance and light weight TLCP reinforced composite filament was generated using the dual extrusion process which allowed the processing of two polymers with different processing temperatures. This composite filament could be directly 3D printed using a benchtop 3D printer. The mechanical properties of 3D printed TLCP composites could rival 3D printed traditional fiber composites but with the potential to have a wider range of processing shapes.

Due to the sharp and corrosion-prone features of steel fibers, there is a demand for ultra-high-performance concrete (UHPC) reinforced with nonmetallic fibers. In this paper, glass fiber (GF) and the high-performance polypropylene (HPP) fiber were selected to prepare UHPC, and the effects of different fibers on the compressive, tensile and bending properties of UHPC were investigated, experimentally and numerically. Then, the damage evolution of UHPC was further studied numerically, adopting the concrete damaged plasticity (CDP) model. The difference between the simulation values and experimental values was within 5.0%, verifying the reliability of the numerical model. The results indicate that 2.0% fiber content in UHPC provides better mechanical properties. In addition, the glass fiber was more significant in strengthening the effect. Compared with HPP-UHPC, the compressive, tensile and flexural strength of GF-UHPC increased by about 20%, 30% and 40%, respectively. However, the flexural toughness indexes I5, I10 and I20 of HPP-UHPC were about 1.2, 2.0 and 3.8 times those of GF-UHPC, respectively, showing that the toughening effect of the HPP fiber is better.

Orientadores: Rosa Cristina Cecche Lintz, Marco Antonio Carnio Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Tecnologia Resumo: O concreto possui propriedades estruturais desejáveis como a resistência à compressão elevada, a rigidez e a durabilidade, mas, ao mesmo tempo, apresenta algumas limitações, como a baixa capacidade de deformação e a rápida propagação de fissuras quando submetido a esforços de tração. A utilização de fibras como material de reforço é uma alternativa para minimizar as limitações deste material. O objetivo deste estudo é avaliar o comportamento mecânico do Concreto Reforçado com Fibras de Vidro (CRFV) e verificar a viabilidade da aplicação do CRFV em peças de pavimento intertravado. A escolha do traço foi feita levando-se em consideração a norma brasileira que estabelece para pavimentos com tráfego de pedestres, veículos leves e veículos comerciais de linha resistência característica à compressão mínima de 35 MPa e para pavimentos com tráfego de veículos especiais e solicitações capazes de produzir efeitos de abrasão acentuados resistência característica à compressão mínima de 50 MPa. A análise dos resultados obtidos permite concluir que a adição de fibras ao concreto proporciona aumento na resistência à tração na flexão e a resistência residual pós-fissuração aumenta com o teor crescente de fibras de vidro na mistura. Verificou-se também um aumento na resistência à compressão das peças de pavimento intertravado moldadas com o concreto reforçado com fibra de vidro possibilitando a aplicação deste traço em pavimentos com tráfego de veículos especiais, de acordo com os limites estabelecidos pela norma brasileira Abstract: The concrete has desirable structural properties such as high compressive strength, stiffness and durability, but at the same time it has some limitations such as low deformability and rapid crack propagation when subjected to tensile stresses. The use of fibers as reinforcement material for the concrete is an alternative to minimize the limitations of this material. The objective of this report is to evaluate the mechanical behavior of glass fiber reinforced concrete (GFRC) and verify the viability of the application of GFRC in interlocked floor blocks. The choice of recipe was made assuming the Brazilian Standard establishes floor with pedestrian traffic, light vehicles and line commercial vehicles minimum characteristic compressive strength of 35 MPa and special vehicle traffic floors and requests can produce marked effects of abrasion minimum characteristic compressive strength of 50 MPa. The analysis of the results shows that the addition of concrete to the fibers provides increased flexural tensile strength and residual flexural tensile strength post-cracking increases with increasing content glass fibers in the mixture. It was also verified an increase in the compressive strength of interlocked floor blocks made with glass fiber reinforced concrete making it possible the application of these recipe in the floors with special vehicle traffic, in accordance with the limits set by the Brazilian Standard Mestrado Ciência dos Materiais Mestra em Tecnologia

Chiang Mai Dental Journal, 42, 3, 57-64

The focus of this study is the development of innovative and sustainable geopolymer composites with improved elevated temperatures performances. To minimize production related costs and support a circular economy model, phosphate sludge and MK are chosen as precursors for alkaline activation, and glass fibers as reinforcement material. The geopolymer composites were prepared by incorporating glass fibers in a geopolymer matrix based on a mixture of metakaolin and PS in a ratio of 50% and with amounts ranging from 0.25% to 1% of fibers. The developed composites were assessed in terms of physical characteristics, microstructural properties and flexural strength prior to and after introduction to higher temperatures. The findings demonstrated that PS based geopolymer matrix flexural strength decreased in the region of temperature between 25 and 600 °C, but increased progressively at higher temperatures, achieving a gain of 3.2% at 1000 °C. The same trend was followed after glass fiber incorporation, leading to a more significant gain of about 16.5% with a 1% fiber content up to 1000 °C. This behavior was assigned to the decomposition of carbonate content of PS at 600 °C as well as to the crystallization of the geopolymer matrix at higher temperatures.

Combining two types of reinforcement fiber in a common matrix may lead to different failure modes such as micro-cracks between the layers when the structure is subjected to lower stress levels. Real-time damage detection should be integrated into the hybrid composite structure to provide structural integrity and mitigate this problem. This paper outlines the working mechanisms and the fabrication of an integrated capacitive sensor in an intra-ply hybrid composite (2 × 2 twill weave). Uniaxial tensile and flexural tests were conducted to characterize the proposed sensor and provide self-sensing functionality (smart structure). The sensitivity and repeatability of the capacitive sensor were measured to be around 1.3 and 185 µΔC/Co, respectively. The results illustrate that onset of damage between layers can be detected by in situ monitoring. It can be seen that the initial damage was detected at the turning point where the relative change in capacitance begins to reduce while the load increases. Finite element modeling was also constructed to analyze the test results and explain the reasons behind the turning point. It was shown that the carbon yarns experienced high transverse shear stress (τxz) in the crimp region, leading to inter-fiber cracks.

[ES] En el ámbito de los materiales compuestos o composites para la construcción, el cemento reforzado con fibras de vidrio (GRC, del inglés glass fiber reinforced cement) es el más extensamente utilizado, por sus excelentes propiedades mecánicas (resistencia a flexión y tenacidad). Sin embargo, la durabilidad de estos composites se ha demostrado crítica, y es necesario proponer alternativas. Las fibras usadas, de carácter álcali-resistente (fibras AR, formadas por agrupación de filamentos), son atacadas por el medio agresivo que impone el cemento hidratado. Una alternativa interesante, desde el punto de vista tecnológico, es la incorporación de materiales cementantes suplementarios de carácter puzolánico. El objetivo del presente trabajo es estudiar la influencia de las diferentes adiciones activas en morteros de GRC, observando el comportamiento de los elementos constitutivos del material en condiciones normales de curado, y también al ser sometidos a procesos de envejecimiento controlado. Asimismo, se analiza el comportamiento de los nuevos composites sometidos a diferentes medios agresivos, evaluando la durabilidad y la mejora de los compuestos por medio de la determinación de sus propiedades mecánicas, químicas y físicas. Se han elaborado probetas de GRC a través del procedimiento de premezcla (premix) y se han determinado sus propiedades mecánicas (resistencia a flexión, tenacidad y módulo de elasticidad). Adicionalmente, se han cuantificado las ganancias de resistencia al comparar composites GRC basados en cemento Portland (especímenes control) con otros en los que se ha sustituido hasta el 60% de dicho cemento por adiciones puzolánicas. Al objeto de mejorar la reactividad de las puzolanas, en algunos casos se ha implementado un aumento de su finura a través de la molienda (cenizas volantes molidas, CVm) o de procesos de sonicación (humo de sílice sonicado, HSS). Los especímenes de GRC han sido sometidos a un proceso de envejecimiento (tratamiento en agua a 55ºC durante un período prolongado) y se ha observado un empeoramiento muy importante de la resistencia a flexión y la tenacidad de aquellos que poseen solamente cemento Pórtland como componente cementante. Los composites GRC que contienen cantidades elevadas de puzolana (60% de CVm) o mezclas de puzolanas (50%CVm / 10%HSS, 50%CVm / 10%FCC) presentan una mejora sustancial de las propiedades mecánicas con respecto a los GRC control. La mejora de estos sistemas GRC con elevados porcentajes de puzolanas reactivas se han confirmado a través de estudios físicos y físico - químicos: evaluación de densidad, absorción, estudios microscópicos (lupa y microscopía electrónica de barrido) y análisis termogravimétrico. En cuanto a la respuesta de los composites GRC frente a diferentes disoluciones agresivas, se ha demostrado el efecto beneficioso de la presencia de puzolanas. Después de la exposición de los morteros de GRC a una disolución de NH4Cl, el comportamiento mecánico de los morteros puzolánicos se mantiene por encima del mortero GRC control: esto se debe a la relación directa existente con el incremento de la densidad y la disminución de grado de absorción del composite con la sustitución puzolánica. Al evaluar las propiedades de los morteros de GRC después de su exposición a una disolución de H2SO4, se observan diferencias muy importantes en la evolución de la masa, resistencia a flexión y tenacidad: los composites control son más afectados por la acidez del medio, de modo que la pérdida de masa es muy significativa si se compara con los GRC que presentan puzolanas. La estancia en la empresa Saint Gobain Vetrotex, ha permitido confirmar una gran similitud en los resultados obtenidos mediante los procedimientos seguidos en el laboratorio de la UPV (compuestos de GRC premezclado) comparados con las prácticas desarrolladas por el laboratorio de materiales de la empresa (composites de GRC proyectado). Se han evaluado, [CAT] En l'àmbit dels materials compostos o compòsits per a la construcció, el ciment reforçat amb fibres de vidre (GRC, de l'anglès glass fiber reinforced cement) és el més extensament utilitzat, per les seves excel·lents propietats mecàniques (resistència a flexió i tenacitat). No obstant això, la durabilitat d'aquests compòsits s'ha demostrat crítica, i cal proposar alternatives. Les fibres usades, de caràcter àlcali-resistent (fibres AR, formades per agrupació de filaments), són atacades pel medi agressiu que imposa el ciment hidratat. Una alternativa interessant des del punt de vista tecnològic és la incorporació de materials cimentants suplementaris de caràcter putzolànic. L'objectiu d'aquest treball és estudiar la influència de les diferents addicions actives en morters de GRC, observant el comportament dels elements constitutius del material en condicions normals de curat, i també quan son sotmesos a processos d'envelliment controlat. Així mateix, s'analitza el comportament dels nous compòsits sotmesos a diferents mitjans agressius, avaluant la durabilitat i la millora dels compostos mitjançant la determinació de les seves propietats mecàniques, químiques i físiques. S'han elaborat provetes de GRC a través del procediment de mescla prèvia (premix) i s'ha determinat les seves propietats mecàniques (resistència a flexió, tenacitat, mòdul d'elasticitat). Addicionalment s'han quantificat els guanys de resistència al comparar compòsits GRC basats en ciment Portland (espècimens control) amb altres en què s'ha substituït fins al 60% d'aquest ciment per materials putzolànics. A l'objecte de millorar la reactivitat de les putzolanes, en alguns casos s'ha implementat un augment de la seva finor a través de la mòlta (cendres volants mòltes, CVm) o de processos de sonicació (fum de sílice sonicat, HSS). Els espècimens de GRC han estat sotmesos a un procés d'envelliment (tractament en aigua a 55ºC durant un període prolongat) i s'ha observat l'empitjorament molt significatiu de la resistència a flexió i la tenacitat d'aquells que posseeixen solament ciment Pòrtland com a component cimentant. Els compòsits GRC que contenen quantitats elevades de putzolana (60% de CVm) o mescles de putzolanes (50% CVm / 10% HSS, 50% CVm / 10% FCC) presenten una millora substancial de les propietats mecàniques respecte als GRC control. La millora d'aquests sistemes GRC amb elevats percentatges de putzolanes reactives s'han confirmat a través d'estudis físics i fisicoquímics: avaluació de densitat, absorció, estudis microscòpics (lupa i microscòpia electrònica de rastreig) i anàlisi termogravimètric. Pel que fa a la resposta dels compòsits GRC enfront de diferents dissolucions agressives, s'ha demostrat l'efecte beneficiós de la presència de putzolanes. Després de l'exposició dels morters de GRC a una dissolució de NH4Cl, el comportament mecànic dels morters putzolànics es millor que el morter GRC control: això es deu a la relació directa existent amb l'increment de la densitat i la disminució del grau d'absorció del compòsit amb la putzolana. Quan s¿ha avaluat les propietats dels morters de GRC després de la seva exposició a una dissolució H2SO4, s'observen diferències molt importants en l'evolució de la massa, resistència a flexió i tenacitat: els compòsits control són més afectats per l'acidesa del medi, de manera que la pèrdua de massa és molt significativa si es compara amb els GRC que presenten putzolanes. L'estada a l'empresa Saint Gobain Vetrotex, ha permès confirmar una gran similitud en els resultats obtinguts mitjançant els procediments seguits en el laboratori de la UPV (compostos de GRC amb premescla) comparats amb les pràctiques desenvolupades pel laboratori de materials de l'empresa (compostos de GRC projectat). S'han avaluat prototips per a la indústria de l'GRC projectat., [EN] In the field of composite materials for construction, glass fiber reinforced cement (GRC) is the most widely used, due to its excellent mechanical properties (resistance to bending and toughness). However, the durability of these composites has been demonstrated to be critical and alternatives need to be proposed. The used fibers, alkali-resistant (AR fibers, formed by grouping of filaments), are attacked by the aggressive medium imposed by the hydrated cement. An interesting alternative, from a technological point of view, is the incorporation of supplementary cementitious materials of pozzolanic behaviour. The purpose of this research is to study the influence of the different mineral additions in GRC mortars, observing the behaviour of the constituent elements of the material under normal curing conditions and controlled aging processes. Likewise, the behaviour of new composites subjected to different aggressive environments is analyzed, evaluating the durability and improvement of the compounds by determining their mechanical, chemical and physical properties. GRC specimens have been produced through the premix procedure and their mechanical properties (flexural strength, toughness, and modulus of elasticity) have been determined. Additionally, resistance gains have been quantified when comparing GRC composites based on Portland cement (control specimens) with others in which up to 60% of that cement has been replaced by pozzolanic additions. In order to improve the reactivity of pozzolans, in some cases an increase in its fineness has been implemented through grinding (ground fly ash, CVm) or sonication processes (sonicated silica fume, HSS). The GRC specimens have been subjected to an aging process (treatment in water at 55ºC for an extended period) and worsening of the flexural strength and toughness of those who only have Portland cement as cementitious component has been observed. GRC composites containing high amounts of pozzolan (60% CVm) or mixtures of pozzolans (50% CVm / 10% HSS, 50% CVm / 10% FCC) show a substantial improvement in mechanical properties compared to the control GRC. The improvement of these GRC systems with high percentages of reactive pozzolans have been confirmed through physical and physical-chemical studies: evaluation of density, absorption, microscopic studies (magnifying glass and scanning electron microscopy), and thermogravimetric analysis. Regarding the response of GRC composites against different aggressive solutions, the beneficial effect of the presence of pozzolans has been demonstrated. After the exposure of the GRC mortars to a NH4Cl solution, the mechanical behavior of pozzolanic mortars remains above that of the control GRC mortar: this is due to the direct relationship existing with the increase in density and the decrease in the absorption of the composite with the pozzolanic replacement. When evaluating the properties of GRC mortars after exposure to an H2SO4 solution, very important differences are observed in the evolution of the mass, flexural strength and toughness: the control composites are more affected by the acidity of the medium, so that the loss of mass is very significant when compared to the GRCs that present pozzolans. The stay at the Saint Gobain Vetrotex company has confirmed a great similarity to the results obtained by the procedures followed at the UPV laboratory (premixed GRC compounds) compared to the practices developed by the company's materials laboratory (composites of projected GRC). Scalable prototypes have been assessed for the projected GRC industry.

Introduction: Polymethyl methacrylate (PMMA) has been widely accepted and used in dentistry owing to its working characteristics, aesthetics and stability in the oral environment, ease in manipulation, and inexpensive processing methods and equipment. Aim and Objectives: The aim of this study was to evaluate the flexural strength of a high-impact PMMA denture base resin material and flexural strength of a commonly available heat cure PMMA denture base material with Kevlar, glass, and nylon fibers. Materials and Methods: The test samples were studied under two groups. The Group I (control group) comprised pre-reinforced PMMA (Lucitone 199; Dentsply Sirona Prosthetics, York, Pennsylvania, USA) consisting of 12 samples and second group comprised regular PMMA (DPI, Mumbai, India) reinforced with different fibers. The second test group was further divided into three subgroups as Group 2, Group 3, and Group 4 comprising 12 samples each designated by the letters a–l. All the samples were marked on both ends. A total of 48 samples were tested. Results were analyzed and any P value ≤0.05 was considered as statistically significant (t test). Results: All the 48 specimens were subjected to a 3-point bending test on a universal testing machine (MultiTest 10-i, Sterling, VA, USA) at a cross-head rate of 2 mm/min. A load was applied on each specimen by a centrally located rod until fracture occurred; span length taken was 50 mm. Flexural strength was then calculated. Conclusion: Reinforcement of conventional denture base resin with nylon and glass fibers showed statistical significance in the flexural strength values when compared to unreinforced high impact of denture base resin.

This research studied the effect of nano silica particles on wear behavior test , ultimate tensile strength ,impact strength, fracture toughness and hardness shore D of specimens composite material. The hand-lay-up method is used to preparation of specimens established from unsaturated polyester resin matrix reinforcement with 4% weight fraction glass fiber (chopped / woven) mat and 1%, 3%, 5% weight fraction of nano silica particle. The nano silica particles used in this study has an average size of (less than 45nm). The results showed that the specimen (up+4% woven glass fiber+5% nano SiO2) gives better mechanical properties include ultimate tensile strength, impact strength, fracture toughness and hardness shore D (110 MPa, 13.7 K.J/m2 , 18.92 MPa.m1/2, 85 shore D) respectively,when compare other specimens. The wear rate decreased from (22.5×10-4 cm3 /N.m) for specimen (pure unsaturated polyester resin) to (0.18×10-4 cm3 /N.m) for specimen (UP+4% woven glass fiber +5% nano SiO2) under parameter 7N (load), 15 minutes (sliding time), 2m/s (sliding speed) and (7 cm) sliding distance.

In the present search, attempts are made to develop the properties of PMMA resin that used for prosthetic complete denture base material, by addition two different types of particles, which included: nano-hydroxyapatite (nHA) particles and micro-zirconia (ZrO2) particles that added with different volume fractions of (1, 2 and 3) % to poly methyl methacrylate (PMMA), as cold cured resin. Also woven glass fiber kind (Eglass) and woven Kevlar fiber kind (49), it were added with a fixed volume fraction of 5 % to PMMA composites. In this work the composite prosthetic dentures specimens preparation was done by using (Hand Lay-Up) method as six groups which includes: the first group consists of PMMA resin reinforced by nHA particles, the second group consists of PMMA resin reinforced by ZrO2 particles, the third group consists of (PMMA-nHA) and glass fiber layer as laminated composite , the fourth group consists of (PMMA-ZrO2) and glass fiber layer, the fifth group consists of (PMMA-nHA) and Kevlar fiber layer and the sixth group consists of (PMMA-ZrO2) and Kevlar fiber layer. The experimental part of this work included performing tensile test. In addition, morphology test was done by (SEM). The result of this experimental research shows that the values of tensile strength and modulus of elasticity increased with increasing the volume fraction of (nHA and ZrO2) particles for all groups specimens, and all values of elongation decreased with increasing volume fraction of (nHA and ZrO2) particles. And the composite prosthetic dentures (PMMA-ZrO2) show greater values for tensile strength and modulus of elasticity properties. While, the reinforcement by nHA particles had shown greater values for elongation for all groups’ specimens. Also the results shown the maximum values for hybrid laminated composite materials for tensile strength and modulus of elasticity properties is obtained in hybrid laminated composite materials for sixth groups’ specimens. While the maximum value for elongation is obtained for first groups’ specimens.

In the present search, attempts are made to develop the properties of PMMA resin that used for upper and lower prosthesis complete denture, by addition two different types of particles, which included: nano-hydroxyapatite (nHA) particles and micro-zirconia (ZrO2) particles that added with different volume fractions of (1%, 2% and 3%) to poly methyl methacrylate (PMMA) cold cured resin as new fluid resin as a matrix. Also woven glass fiber kind (E-glass) and woven Kevlar fiber kind (49), it were added with a fixed volume fraction of (5%) to PMMA composites. In this work the composite prosthetic dentures specimens preparation was done by using (Hand Lay-Up) method as six groups which includes: the first group consists of PMMA resin reinforced by nHA particles, the second group consists of PMMA resin reinforced by ZrO2 particles, the third group consists of (PMMA-nHA) and glass fiber layer as laminated composite , the fourth group consists of (PMMA-ZrO2) and glass fiber layer, the fifth group consists of (PMMA-nHA) and Kevlar fiber layer and the sixth group consists of (PMMA-ZrO2) and Kevlar fiber layer. The compression test result shows that the values of compression strength increased with increasing the volume fraction of (nHA and ZrO2) particles for all groups’ specimens. And the results showed the (PMMA-ZrO2) composite has greater values for compression strength. As well as the results shows that the maximum value of compression strength for hybrid laminated composite is obtained in hybrid laminated composite materials for fourth groups’ specimens (PMMA-ZrO2-5% Glass Fiber). Whereas the values of fatigue strength of hybrid laminated composite (PMMA-5% Kevlar fiber-3% nHA), it was higher than the fatigue strength of hybrid laminated composite (PMMA-5% Glass fiber-3% nHA) and the base material (Pure PMMA). The fatigue strength values at (106 ) loading Cycle for these specimens were (52, 38 and 15 MPa) respectively.

The current study focused on the manufacturing and development properties of upper prosthesis complete denture from composite materials with the basis cold cured resin of poly methyl methacrylate as new fluid resin and reinforced materials by two different types of particles (nano-hydroxyapatite (nHA), micro zirconia (ZrO2)), that added with different volume fractions of (1%, 2% and 3%), and the different types of woven fibers (Glass fiber, Kevlar fiber), it were added with a fixed volume fraction of (5%) to PMMA composites. Specimens’ consist of a six groups where prepared by using (Hand Lay-Up) method from the composites materials and hybrid laminated composites materials. This research includes theoretical and numerical studies by using finite element method to confirming the experimental results of the effect of selected volume fractions of these particles and fibers on the (total deformation distribution, equivalent elastic strain and equivalent Von Mises stress) of the composite prosthetic dentures. The theoretical part included calculations the values of theoretical safety factor and Poisson's ratio. While the numerical part based on finite element method (F.E.M), which was performed by using program (ANSYS-15) to analyze the prepared of denture composite materials and evaluate its characteristics which represent total deformation distribution, equivalent stress and equivalent elastic strain. This was performed by obtaining twenty one models for the PMMA composite dental prostheses which were treated as three dimension structure. The numerical results of the F.E.A showed coincided with some of the experimental results.

The paper presents the results of experimental research on unstrengthened and strengthened laminated veneer beams subjected to 4-point bending. Aramid, glass and carbon sheets with high tensile strength (HS) and ultra-high modulus of elasticity (UHM) glued to external surfaces with an epoxy resin adhesive were used as reinforcement. Two reinforcement layouts were used: (1) sheets glued along the bottom surface and (2) sheets glued to the bottom and side surfaces. Based on the test results, the flexural strength, flexural ductility and stiffness were estimated. Compared to the reference beams, the maximum bending moment was higher by 15%, 20%, 30% and by 16%, 22% and 35% for the Aramid Fiber Reinforced Polymers (AFRP), Glass Fiber Reinforced Polymers (GFRP) and Carbon Fiber Reinforced Polymers (CFRP) HS sheets, respectively. There was no significant increase in the flexural bending capacity for beams reinforced with UHM CFRP sheets. Similar values of bending ductility indices based on deflection and energy absorption were obtained. Higher increases in ductility were observed for AFRP, GFRP and CFRP HS sheets in “U” reinforcement layout. The average increase in bending stiffness coefficient ranged from 8% for AFRP sheets to 33% for UHM CFRP sheets compared to the reference beams.

Coatings of graphene oxide over two substrates of glass-fibre and polystyrene were obtained by electrophoretic deposition (EPD). A chemical reduction of graphene oxide by exposure to hydrazine hydrate at 100 °C significantly changes the interfacial interaction with the substrate as well as the tribology. Spectroscopic techniques like Fourier transform infrared, Raman spectroscopy, X-ray photoelectron spectroscopy and X-ray diffraction showed that the treatment with hydrazine replaces oxygen functional groups and also induces roughness, a structural disorder and decreases the interlayer separation in the transition from graphene oxide (GO) to reduced graphene oxide (rGO). Treatment with hydrazine reduces adhesion and friction force against diamond like carbon coated Si probe (DLC AFM) at the basal plain of the coatings. Investigation at the edges revealed that the presence of oxygenic functional groups leads to higher shear strength with glass-fibre and polystyrene which reduces after treatment with hydrazine.

Fiber Reinforced Polymers (FRP) material are proposed and implemented for civil engineering applications for both retrofitting of existing structures and building of new facilities. In new construction realizations, FRP elements are frequently manufactured using pultrusion that represents a high rate manufacturing method, however characterized by a prevalent longitudinal fiber orientation with consequently weakness along the directions different than the longitudinal one. The intrinsic orthotropy, the presence of defects due to the manufacturing processes and the brittle failure mechanisms are peculiarities that decelerate their wide applications, so that are an open issue to be solved. In this regard, the present work experimentally investigates the local behavior of a commercial Pultruded I-shaped Glass FRP (PGFRP) element, in order to: 1) evaluate the mechanical properties of the material according to different fiber orientations, 2) check the validity of the Tsai Hill Criterion and 3) investigate the capacity of the web-flange (WF) junction, that is a recognized weak point, through a novel and simple experimental test.

Fiber reinforced Polymer (FRP) composites are currently employed in the civil engineering industry as externally bonded reinforcement (EBR) of existing reinforced concrete (RC) and masonry structures and as internal reinforcement of concrete elements as an alternative to steel reinforcing bars. Carbon FRP (CFRP) composites are mainly used for EBR applications whereas glass FRP (GFRP) bars are employed as internal reinforcement of concrete elements. This paper sheds light into the effect of different aggressive environments on the tensile behavior of reinforcing GFRP bars. 356 results of tensile tests of GFRP bars subjected to hot dry and humid air, different alkali environments, salt solutions with various concentrations, and plain and distillated water were collected from the literature. According to the “design by testing” procedure provided by EN 1990, a statistical analysis of the results was carried out to calibrate environmental reduction factors able to provide reliable estimations of the long-term behavior of GFRP bars subjected to different exposure conditions. For a given aggressive environment, a clear and unique degradation trend could not be identified, which points out the need of a standard testing procedure able to provide reliable and repeatable results.

Rapid heat cycle molding (RHCM) of reinforced thermoplastics is increasingly used in order to obtain high surface quality on structural parts. In this work, the effect of RHCM on both microstructure and ultimate tensile strength of polypropylene reinforced with 30 wt% long glass fibers was investigated. Micro X-ray computed tomography was employed to allow a non-destructive assessment of fibers orientation and internal porosity, while optical measurements were used to evaluate the residual fibers length distribution. The experimental results indicated that an increase of injection velocity always results in a decrease of ultimate tensile stress, due to higher fiber breakage. This effect is partly attenuated at low mold temperature, due to an increase of fiber orientation. On the other hand, when using RHCM an increase of injection velocity results in a greater decrease of ultimate tensile stress, due to the reduction of both fiber length and fiber orientation.

In recent years, there has been a great deal of interest in lightweight vehicle design due to regulations about reducing fuel consumption and emissions. Lightweight design of vehicle components is one of the most important research topics in vehicle design. Developing the optimum structure in the early stages of design process is very important for minimizing the vehicle weight and production costs. In this paper, an automobile hinge component has been developed using PA66 GF60 glass fiber-reinforced polyamide composite materials instead of conventional steel. The automobile hinge component has been conceived using computer aided design software. Topology optimization was made under specific loadings subject to the constraints of finite element method analysis. As a result of this study, optimum dimensions of the component have been obtained and the weight of the component has been reduced via structural topology optimization techniques while satisfying displacement and stress conditions. The results show that composite materials are an important alterative in lightweight vehicle design.

Additive manufacturing is used in several industrial sectors where polymers and metals are established materials. Different academic studies prove that additive manufacturing methods can be applied on glass materials using powder or fiber based material sources. In terms of quartz glass, with melting temperatures around 2200°C, laser sources are used to achieve the necessary intensities. In the present study, additive manufacturing of quartz glass is achieved by melting a quartz glass fiber with a CO 2 laser source. A combined laser head focusses the laser radiation onto the glass fiber in order to melt the fiber. A three axis system is used to move the printing stage and glass substrate. The experimental investigations show that CO 2 -laser glass deposition printing allows for the creation of arbitrary 3D quartz glass structures. This method is envisioned to replace conventional manual glass manufacturing processes for production of complex hollow glass structures which are present in the medical sector.

In this work, laminated polyester thermoset composites based on palm tree fibers extracted from palms leaflets and glass mats fibers were manufactured to develop hybrid compositions with good mechanical properties; the mixture of fibers was elaborated to not exceed 25 vol.%. Samples were prepared with a resin transfer molding (RTM) method and mechanically characterized using tensile and flexural, hardness, and impact tests, and ultrasonic waves as a non-destructive technique. The water sorption of these composite materials was carried out in addition to solar irradiation aging for approximately 300 days to predict the applicability and the long-term performance of the manufactured composites. Results have shown that the use of glass fibers significantly increased all properties; however, an optimum combination of the mixture could be interesting and could be developed with less glass sheet and more natural fibers, which is the goal of this study. On the other hand, exposure to natural sunlight deteriorated the mechanical resistance of the neat resin after only 60 days, while the composites kept high mechanical resistance for 365 days of exposure.

This paper aims to present an experimental investigation on the behavior of web-flange junctions (WFJs) rotational stiffness of pultruded fiber-reinforced polymer composites (FRP). Channels and I-sections were tested using a simple set-up, which was developed in order to experimentally characterize the junctions in a direct manner. The Digital Image Correlation (DIC) technique was used, allowing overall deflections and relative rotations between web and flange to be monitored. The WFJs' imperfections were analyzed through an optical microscope and correlated with the cracks' formation. Further, damage thresholds are identified using available stress equations for curved composite members and lower bound functions are proposed to simulate the junction stiffness retention. Finally, two Equations are developed in order to analytically predict pultruded junctions' rotational stiffness per unit of width. In general, the theoretical and experimental results agreed fairly well, with a maximum difference of 24% for I-sections and 38% for channels.

In the current study, the utilization of glass and nylon fibers in various percentages are added to enhance the mechanical performance of peach shell lightweight concrete. Glass and nylon fibers were added at 2%, 4%, 6%, and 8% by cement weight. The results showed that, as we added the glass and nylon fibers, the density of peach shell concrete was reduced by 6.6%, and the compressive, split tensile and flexural strength were enhanced by 10.20%, 60.1%, and 63.49%. The highest strength that was obtained in compressive, split tensile, and flexural strength at 56 days was 29.4 MPa, 5.2 MPa, and 6.3 MPa, respectively, with 6% of glass fiber in peach shell concrete. Mechanical test results showed that post-failure toughness and modulus of elasticity of peach shell concrete is enhanced with the utilization of fibers. To verify our lab results, a statistical analysis, such as response surface methodology, was performed to make a statistical model, it was confirmed by both lab results and statistical analysis that the mechanical performance of peach shell concrete could be significantly improved by adding glass fibers as compared to nylon fibers. With the use of fibers, the water absorption and porosity were slightly increased. Hence, the glass and nylon fibers can be used to improve the peach shell concrete mechanical properties to make concrete eco-friendly, sustainable, and lightweight.

The purpose of this paper is to investigate the mechanisms of cracking and failure in fiber metal laminates (FMLs) subjected to 3-point bending. Two types of laminates, based on the glass/epoxy and carbon/epoxy composites, were selected for the study. The paper presents the failures of matrix and fibers as well as the effects of different thicknesses of metal layers on the tested laminates. The mechanisms of failure observed for the two tested types of fibers with uniform thickness of aluminum sheets seem similar. The results demonstrate that the tested laminates exhibit the following failure modes: fiber breakage, matrix cracking, fiber/matrix debonding, delamination, and anodic layer failure. Given the behavior of aluminum under the compressive and tensile stresses, the aluminum layer acts as a barrier preventing FML failure during bending. In addition to aluminum layer thickness, the fiber type and composite layer directions are also important factors to be considered.

A study was undertaken to investigate the shear strength parameters of treated sands reinforced with randomly distributed glass fibers by carrying out direct shear test after seven days curing periods. Firstly, we studied the fiber content and fiber length effect on the peak shear strength on samples. The second part gives a parametric analysis on the effect of glass fiber and clinker residue content on the shear strength parameters for two types of uniform Algerian sands having different particle sizes (Chlef sand and Rass sand) with an average relative density Dr = 50%. Finally, the test results show that the combination of glass fiber and clinker residue content can effectively improve the shear strength parameters of soil in comparison with unreinforced soil. For instance, there is a significant gain for the cohesion and friction angle of reinforced sand of Chlef. Compared to unreinforced sand, the cohesion for sand reinforced with different ratios of clinker residue increased by 4.36 to 43.08 kPa for Chlef sand and by 3.1 to 28.64 kPa for Rass sand. The feature friction angles increased from 38.73° to 43.01° (+4.28°), and after the treatment, clinker residue content of soil evaluated to 5% (WRC = 5%).

Lightweight and electrically nonconductive fiber reinforced hybrid epoxy composites have gained attentiveness within specific applications such as marine, automotive and aerospace. However, the components made from these materials can be subjected to significant erosion when they are used in shipping industries and water sports equipment. The present paper proposes to address this challenge by analysing the erosion resistance of glass fiber and silicon carbide (SiC) reinforced epoxy composites. Taguchi's methodology was adopted for the experimentation using the L9 orthogonal array. Impingement angle, erodent type, and workpiece reinforcement were used as input process parameters, whereas erosion loss from the composite was perceived as a response parameter. Regression coefficients and equations for the erosion loss were derived from the regression analysis. The genetic algorithm (GA) was proposed to obtain authentication against Taguchi's methodology. The surface analysis of eroded composites and erodent particles was later evaluated by a Scanning Electron Microscope (SEM). The comparative outcomes achieved from GA and Taguchi's methodology indicates that the angle of impingement and reinforcement size are the primary aspects that affect the erosion resistance of the composite surface.

Interfacial interaction is one of the most important factors that affect the mechanical properties of the fiber reinforced composites. The effect of fabrics&prime, sizing removal from glass fibers&rsquo, surface by thermal treatment on the mechanical characteristics of polyethersulfone based composites at different fiber to polymer weight ratios was investigated. Three fiber to polymer weight ratios of 50/50, 60/40, and 70/30 were studied. Flexural and shear tests were carried out to illustrate the mechanical properties of the composites, the structure was studied using Fourier-transform infrared spectroscopy and scanning electron microscopy. It was shown that solution impregnation of glass fabrics with polyethersulfone before compression molding allows to achieve good mechanical properties of composites. The thermal treatment of glass fabrics before impregnation results in an increase in flexural and shear strength for all the composites due to the improvement of fiber&ndash, matrix interaction.

In this paper, we report a study on the effects of different ethylene copolymers in improving the impact strength of a fiber-reinforced composite based on a recycled poly(ethylene terephthalate) (rPET) from post-consumer bottles. Different ethylene copolymers have been selected in order to evaluate the effects of the polar co-monomer chemical structure and content. The composite mixtures were prepared via melt extrusion, and the samples were manufactured by injection molding. Impact strength was evaluated using Izod tests, and a morphological study (FESEM) was performed. As a result, a composite with substantially improved impact properties was designed. This study demonstrates that a post-consumer PET from the municipal waste collection of plastic bottles can be successfully used as a matrix of high-performance, injection-molded composites, suitable for use in the automotive sector, among others, with no compromise in terms of mechanical requirements or thermal stability.

In this work, a novel nanomaterial deposition technique involving the triboelectrification (TE) of glass fibers (GF) to create attractive charges on their surface was investigated. Through TE, continuous GF were positively charged thus, attracting negatively charged graphene oxide (GO) nanoparticles dispersed in a solution. The electrical charges on the glass fibers surface increased with the intensity of the TE process. The deposited GO coating was then chemically treated to obtain reduced graphene oxide (rGO) on the surface of GFs. The amount of coating obtained increased with the GO solution concentration used during the deposition process, as revealed by FESEM analysis. However, the same increment could not be noticed as a function of the intensity of the process. Both uncoated and coated GF were used to obtain single fiber microcomposites by using a bicomponent epoxy matrix. The fiber/matrix interfacial shear strength was evaluated through micro debonding tests, which revealed an increment of fiber/matrix adhesion up to 45% for rGO coated GF in comparison to the uncoated ones. A slight improvement in the electrical conductivity of rGO coated fibers through TE compared to conventional dip coating was also observed in terms of volumetric resistivity by a four-point probe setup.

In this work, the effects of processing parameters including temperature, time, and pressure on the properties of amorphous polyvinyl chloride (PVC)/fiberglass thermoplastic composite laminates were evaluated. The film stacking and hot pressing procedure was used to produce the composite laminates, and samples with [0/90]10 layup and thickness of 3 mm were produced. Flexural strength and modulus of the samples were measured using three-point bending test (according to ASTM D790 standard test method), and microscopic images were used to evaluate the failure mechanisms and impregnation quality. The effects of the parameters on the strength were studied using analysis of variance (ANOVA), and it was found that processing temperature has the maximum effect on the products strength and increase of the temperature up to 230°C increases the flexural strength while more increase of temperature results in the matrix degradation and strength reduction. Also, processing time improves the wetting and impregnation quality; however, more increase of the processing time results in the matrix degradation and excessive reduction of the strength.

This work is focused on the characterization of a novel vanadium pentoxide catalysts on a glass-fiber support. The catalyst support consists of a non-porous glass-fiber fabric covered with an additional external surface layer of porous secondary support of SiO2. The vanadia active component is synthesized from vanadyl oxalate precursor by means of an impulse surface thermo-synthesis method. Such catalysts demonstrate high activity and appropriate selectivity in the reaction of H2S oxidation by oxygen into sulfur in the practically important temperature range below 200°C. According to the characterization data, the freshly prepared vanadia catalyst partially consists of mostly the amorphous and badly ordered vanadia with some part of the wellcrystallized V2O5 phase. Under the reaction conditions the main part of vanadia in the catalyst remains in the amorphous V2O5 form, while the less part becomes reduces into of VO2 and other vanadium oxides (such as VO, V2O3 V3O7 and V4O9). Most probably, the crystallized V2O5 in course of reaction is responsible for the deep oxidation of hydrogen sulphide into SO2, while the lower vanadium oxides promote the selective H2S oxidation into elemental sulfur.

Presently, fiber reinforced materials are used for many industrial applications. Laser transmission welding (LTW) is a suitable method to join these materials. For multiple thermoplastics, the weld seam quality is affected by the amount of moisture content in the joining members. For LTW, heat is applied to the welding members and water in the composite changes phase from liquid to gas. Increasing the gas content can lead to detrimental cavities in the weld seam. Therefore, experiments were performed to investigate the influence of the laser focal geometry on the generation of cavities. Different focal geometries lead to different levels of process heat generation which affects the amount of vaporization. The experiments were conducted with endless glass fiber reinforced polyetherimide and endless carbon fiber reinforced polyetherimide. These samples were tested for their weld seam strength and the results were correlated to the moisture content and laser beam geometry. © 2016 The Authors.

Glass fiber-reinforced polyester composite (GFRPs) scraps from manufacturing of polyester laminates were pyrolyzed at 500, 550 and 600°C in an 70 Kg innovative batch pilot plant that processes whole parts. The presence of a hydraulic guard guarantees the safety of the process. The influence of the maximum process temperature on yields and chemical-physical properties of pyrolysis products was investigated: the oil fraction was analysed by GC-MS, Viscometer and XRF, while the gas fraction was monitored online during the entire pyrolysis process by µ-GC. Substantial fractions of methane (20.7 vol %) and hydrogen (11.5 vol %) were produced. The solid residue (glass fibers covered by a thin carbonaceous layer) underwent an oxidative process at 500 and 600°C at different residence times to provide clean glass fibers free of organic residues. The effects of both pyrolysis and oxidative step on the glass fibers, obtained in different process conditions, were evaluated by SEM and Raman spectroscopy.