Glass Fiber Content Research Articles

Analysis of open-hole-tension plates made of short fibre thermoplastic and reinforced with continuous fibre tailored inserts

In the present paper, the influence of tailored load introduction inserts applied to a bolt-loaded open-hole injection plate with different short glass fibre content is investigated. The tailored load introduction inserts made with a Tailored Fibre Placement (TFP) process, as well as open-hole injection plates without an insert were considered as reference samples. The samples were tested under tensile bolt-loading. The influence of the TFP-inserts on the load bearing properties of the open-hole injection plates was investigated. The test results show a huge increase of the load-carrying ability of the short-glass-fibre specimens when TFP-inserts are integrated. Moreover, the damage tolerance was dramatically improved as the specimens with integrated TFP-inserts did not fail abruptly and a residual strength higher than the strength of the test specimen without insert could be observed. However, the strength of the test specimen with integrated insert did not exceed the strength of the insert itself in most cases.

Mechanical behavior and dynamic damage constitutive model of glass fiber-reinforced Vinyl Ester with different fiber contents.

Glass fiber-reinforced plastics (GFRP) based on polymer materials are widely used in lightweight impac-resistant structure design. In the process of design and development, it is very important to clarify the mechanical behavior under dynamic load to improve the product performance. Therefore, in this paper, Quasi-stati and dynamic compression behaviors of unidirectional continuous glass fiber-reinforced vinyl ester (GF/VE) composites with five kinds of fiber contents in the fiber direction were measured by an electro-hydraulic servo experiment system and a split Hopkinson pressure bar, and damage evolution of the material is analyzed by observing the microstructure of the cross section of the material. Results show that: The content of glass fiber affects the wettability between fiber and matrix, and the failure mechanism of material at high strain rate; Under quasi-static conditions, higher glass fiber content yields greater failure strength; Under dynamic conditions, as glass fiber content increases, toughness decreases, and the peak stress first increases and then decreases. Finally, the nonlinear viscoelastic constitutive model with damage evolution is derived, which can be used to predict the impact resistance of new composite structures in the product development and design stage and reduce the development cycle.

Influence of Concentration of Carbon and Glass Fibers, Melt Viscosity, and Number of Extrusions on the Porosity of Composites Based on Polyphenylene Sulphone, Polyethyrimide and Polyphenylene Sulfide

A comparative analysis of the effect on the porosity of composite filaments based on polyphenylene sulfone, polyetherimide and polyphenylene sulfide with discrete fibrous fillers, such factors as the filler concentration, melt viscosity and number of extrusion passes, was carried out. It is shown that with increasing filler content and decreasing melt viscosity, the porosity of composite filaments enhances. Upon repeated extrusion carbon-filled composites, a decrease in porosity is observed, however for glass-filled samples an increase in porosity is occurred. A comparative analysis showed that the filament samples based on polyetherimide have a higher porosity. The most resistant to pore formation are polyphenylene sulfone-based samples.

Mechanical properties and microstructure of glass fiber and polypropylene fiber reinforced concrete: An experimental study

This paper presents the results of a comprehensive experimental work investigating the effect of glass fiber (GF) and polypropylene fiber (PPF) on the mechanical and microstructural properties of concrete as a function of the water/binder ratio and fiber content. Different water/binder ratios (0.30 and 0.35), GF and PPF contents (0.45, 0.90, and 1.35% by volume fractions), and curing times (7 and 28 d) were used during the experiment to prepare the concrete specimens. The compressive, four-point flexural, and splitting tensile strengths and the full curves of water absorption of the glass-fiber-reinforced concrete (GFRC) and polypropylene-fiber-reinforced concrete (PPFRC) were obtained. The strength differences and water absorption properties of GFRC/PPFRC were analyzed in depth. Scanning electron microscope observation was undertaken to analyze the mechanism of the water/binder ratio and fiber effects. The results showed that the water/binder ratio can affect the optimal fiber content. When discussing the effect of fibers on the improvement of concrete mechanical or microstructural properties, the influence of the water/binder ratio should be considered. The improvement effect of GF on water absorption was significantly superior to that of PPF. When the water/binder ratio was 0.30, the water absorption of GFRC and PPFRC tended to be stable as the test proceeded, while when the water/binder ratio increased to 0.35, the water absorption of the GFRC and PPFRC with the highest fiber dosage still increased with the prolongation of testing time.

Investigation on roundness and taper of holes in drilling GFRP composites with variable weight percentages of glass fiber

Mechanical fastening technique plays a vital role in aerospace and automotive industries because of their ability to make large assemblies in composite materials. However, it is challenging to drill holes in composite materials which are free of defects. Thus, the paper investigates the influence of glass fiber content within the GFRP composites during the drilling operation. Different hole quality parameters such as roundness deviation, delamination, fiber pull-out, taper angle were observed as they contribute to better machinability and improved surface quality while drilling. A radial drilling machine was used to perform the drilling process on the composites keeping a constant rotational speed and feed rate. Only fiber weight percentages were varied. The experimental results exhibited that the drilled surface quality is closely related to the percentage of the fiber content of the specimens. In terms of roundness deviation, delamination, fiber pull-out, and taper angle, a better result is achieved for the composite specimen having comparatively lower glass fiber content.

Properties of fiber reinforced plaster molds for investment casting

In order to improve the performance of plaster molds for investment casting, a diverse content of glass fiber and polypropylene (PP) fiber was incorporated into the slurry for the preparation of a fiber-reinforced mold. The green and fired bending strengths, thermal expansion properties, permeability, and thermal shock resistance of the mold were examined, and the scanning electron microscope (SEM) with energy dispersive spectrometer (EDS) was applied for the observation of fracture morphology. With appropriate content, the introduction of glass fiber was proved to increase the green bending strength and fired bending strength, restrain the thermal expansion and improve the thermal shock resistance of the mold, while the polypropylene fiber added was able to raise the green bending strength and the permeability, reduce the thermal expansion and heighten the thermal shock resistance as well, though the fired bending strength would be weakened slightly. Evenly distributed fibers were capable of enhancing the mechanical properties of the matrix, but agglomerations and bundles of fibers resulting from excessive addition had a negative impact. Meanwhile, it was also manifested that micropores left by ablative polypropylene fibers could improve the permeability and reduce the thermal expansion of the mold, and the fired bending strength would be decreased slightly by the deterioration of continuous structure. Three different ratios of hybrid fiber were employed in plaster molds, which can meet altered requirement of castings. The samples modified with hybrid fiber possessed lower thermal deformation, higher air permeability, and better resistance of thermal shock, while the mechanical strength was equal to the fiber free sample or slightly increased.

Non-destructive measurement of fiber mass content of glass fiber sheet molding compound using Terahertz radiation

Sheet Molding Compounds (SMC), a type of fiber-reinforced polymers, are popular lightweight material due to their handling and processability. The fiber mass content (FMC) as well as the fiber orientation distribution determine mechanical properties of manufactured components. However, local deviations from the intended FMC occur during the production of the semi-finished material as well as during the molding itself. In this contribution, SMC was investigated regarding its properties in the Terahertz (THz) spectrum to non-destructively quantify the local FMC. SMC with different FMC between 38 and 54 wt% was industrially produced and dry glass fibers were added to further increase the glass fiber content. Reference measurements of the FMC were conducted via thermogravimetric analysis and showed a mean deviation from the intended FMC of 2.64 wt%. The peak arrival time, the transmitted energy and the refractive index of the THz signal were determined and assessed regarding their correlation with the FMC. A multivariate regression analysis including backward elimination led to a low bias statistical model between the refractive index and the FMC with a cross-validated root mean square error (RMSE) of 1.33 wt%.

Multi‐scale analysis of short glass fiber‐reinforced polypropylene under monotonic and fatigue loading

AbstractShort fiber‐reinforced polypropylene is largely used in the automotive industry. Fatigue failure is one of the most failure modes observed in this class of materials. In order to better understand the damage mechanisms and plasticity evolution, this article provides an overall experimental investigation of the mechanical properties of a PPGF40 composite (polypropylene matrix reinforced by a 40% weight content of short glass fibers) including monotonic and cyclic loading. The effect of various parameters such as the loading direction, the strain rate, the temperature, and the fatigue are analyzed. The evolutions of the loss of stiffness and plastic strain during monotonic and fatigue tests are analyzed. Self‐heating during cyclic loading is also studied. Moreover, the coupling effect of damage and plasticity is analyzed by plotting the evolution of the relative loss of stiffness vs the plastic strain increment for monotonic and cyclic loadings. For quasi‐static loading, the results emphasize an intrinsic curve independent of the loading direction. Moreover, a sharp increase in the damage and plasticity levels due to the local effect occurring during cyclic loading is observed and correlated to SEM fracture surface analysis.

Adaptation of the geopolymer composite formulation binder to the shaping process

This work aims to adapt a formulation of a geopolymer composite to elaborate complex shapes. Here a hollow cylinder is chosen to investigate different possible solutions: building process according to the formulation. To this end, different content of metakaolin, wollastonite, and glass fibers was used to identify the feasibility of shaping of the geopolymer composites. Hollow cylinder shape was elaborated from different formulations by casting and additive manufacturing (robocasting or Direct Ink Writing) regarding their feasibility. The mechanical properties of the formulations were then analyzed with thermal analysis, compressive and flexural tests, and compared with their way of shaping. The results showed that the viscosity can be mainly controlled by the wollastonite content. The formulations adapted to the robocasting present an optimal mechanical resistance due to a higher amount of reinforcement elements. A formulation that can be cast and robocast has been obtained and presents a compressive strength of 89 MPa and bending strength of 15 MPa. Thus, here some keys are given to design a formulation of geopolymer composite adapted to a shaping process by modifying the metakaolin, wollastonite, and glass fiber content.

Effect of expanded polystyrene on the flexural behavior of lightweight glass fiber reinforced cement

Lightweight glass fiber reinforced cement (LWGRC) with good thermal insulation can be produced by using expanded polystyrene (EPS) particles. In this study, the influence of EPS and glass fiber on the modulus of rupture (MOR) and toughness of GRC was investigated. The fiber mass fraction is 0% ~ 3.6%, and the EPS volume fraction is 0% ~ 36%. No matter how much glass fiber is, the relative MOR has the same proportional relationship with the relative density of LWGRC. The empirical formula based on power function can well show the relationship between relative MOR and relative density. The higher the content of EPS, the more obvious the plastic characteristics of LWGRC. When the content of EPS is in a range of 0% to 18% (by volume), the fracture energy of LWGRC increases with the increase of glass fiber content. When the content of EPS is in the range of 27% to 36% (by volume), the fracture energy of LWGRC with 2.4% (by mass) fiber is higher. Too high or too low content of glass fiber is harmful to the fracture energy of LWGRC.

Glass fibre modified asphalts and the use as a tension belt – pavement service lifetime calculations and economic efficiency

Fibres are added to asphalt surface mixes mainly due to technological reasons. The impact of loose glass fibre reinforcement on the performance characteristics of different asphalt mixes was investigated. On the one hand, the glass fibres were used at Stone Mastic Asphalts as a replacement for cellulose fibres. On the other hand, glass fibres were used as additives for asphalt concrete mixes. A constant glass fibre content of 0.5 mass-% was chosen for the laboratory tests. This paper presents the impact of glass fibres on the fatigue and stiffness performance of asphalt mixes, both determined using cyclic indirect tensile tests. The glass fibre modified asphalts investigated have high-performance characteristics, so that an application of these asphalt mixes as a tension band was examined. In order to assess the use of the glass fibre modified asphalt mixes as tension belts pavement service lifetime calculations and the economic efficiency were considered.

Comparative Study of Glass Fiber Content Measurement Methods for Inspecting Fabrication Quality of Composite Ship Structures

A comparative study of glass fiber content (Gc) measurement methods was conducted using actual glass fiber reinforced plastic laminates from the hull plate of a 26-ton yacht. Two prototype side hull plates with the design Gc (40 wt.%) and higher Gc (64 wt.%) were prepared. Four methods were used to study the samples: the calculation method suggested by classification societies’ rules; two direct measurement methods using either calipers and scales or a hydrometer; and the burn-off method, wherein the resin matrix is combusted from the laminates. The results were compared and analyzed to identify the accuracy and benefits of each method. The rule calculation method was found to be effective if the quality of the manufacturing process is known. However, fabrication errors in the laminate structures cannot be detected. Additionally, while direct methods are used to measure the density of glass fibers using measurements of the densities of raw materials and laminates, the volume of inner defects occurring during the fabrication of laminates could not be considered. Finally, it was found that the burn-off method measures Gc and considers the defect volume (voids) inside laminates as well as the non-uniformity of the external shape.

Multilayer coatings based on the combination of perfluorinated organosilanes and nickel films for injection moulding tools

Different multilayer coatings consisting of NiO and Ni layers supporting a 1H,1H,2H,2H-perfluorooctyltriethoxysilane/1,8-bis(triethoxysilyl)octane (PFOS) layer have been studied as possible alternatives for typical injection moulding tools. The NiO layer has been obtained by thermal annealing of an electroless Ni layer, whereas the PFOS layer was deposited by dip-coating. The physical and chemical properties of the as-coated steel have been studied by FIB-SEM-EDX, AFM, contact angle, Raman spectroscopy, X-ray photoelectron spectroscopy and PM-IRRAS. Furthermore, cyclic voltammetry, linear-sweep voltammetry, EIS and Mott-Schottky analyses were performed to determine the electrochemical properties of the coatings. Thermally grown NiO leads to a nanoporous surface layer with n-semiconducting properties, whereas the addition of the PFOS induced a decrease in the roughness of the studied samples. The corrosion resistance of the thermally grown NiO is strongly improved in comparison to the non-oxidised Ni-coating. Contact angles showed an effective reduction in surface energy on adsorbed PFOS-film. Injection-moulding tests using polyamide (PA6) and polyamide with 30% glass fibre content (PA6-GF30) were performed on a tool coated with PFOS/Ni to assess the anti-adhesive properties of this coating. After 150 cycles, the PFOS/Ni coating displayed remarkable stability, improved wear resistance and anti-adhesion properties to the studied polymers compared with the uncoated and TiN-coated tool.

Analysis of Mechanical Properties of Fiber Reinforced Polymer Mortar

It is studied that effects of different amounts of steel fiber and glass fiber on the compressive strength, flexural strength, and compression ratio and bond strength of styrene-acrylic emulsion modified mortar under different ages. The results show that the compressive strength, flexural strength and bond strength of mortar increase with the increase of steel fiber content, and the toughness improvement effect is obvious. With the increase of glass fiber content, mortar compressive strength, flexural strength and bond strength first increases and then decreases. Combined with SEM analysis and theoretical calculation to analyze the mechanical strength mechanism of fiber reinforced polymer mortar.

Mechanical Properties and Microstructure of Fibre-Reinforced Clay Blended with By-Product Cementitious Materials

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

Effects of glass fiber size and content on microstructures and properties of KNO3-based water-soluble salt core for high pressure die casting

The water-soluble salt core with higher bending strength and toughness is necessary to withstand the high pressure needed to manufacture some complex parts by high pressure die casting (HPDC). In this paper, the effects of glass fiber size and content on microstructures and properties of KNO3-based (KNO3-30 mol%KCl) water-soluble salt core were systematically studied. The results showed that increasing the glass fiber content greatly improved the bending strength and impact toughness of the KNO3-based salt core, decreased the water solubility rate and increased the humidity resistance. In addition, increasing the glass fiber size sharply enhanced the impact toughness of the KNO3-based salt core, while decreasing the bending strength, water solubility rate and humidity resistance. The maximum bending strength and impact toughness of the reinforced KNO3-based salt core with the glass fiber were, respectively, 41.32 ± 0.38 MPa and 2.146 ± 0.108 kJ/m2, which were 55.9% and 315.1% higher than those of the unreinforced KNO3-based salt core, respectively. The microstructures show that the glass fibers were evenly distributed in the KNO3-based salt core, which significantly refined the KCl primary phases, especially for the 12.5-μm glass fiber. Meanwhile, many fiber pull-out holes were observed in the KNO3-based salt cores with 75-μm and 25-μm glass fiber. The grain refinement, fiber pull-out and crack deflection were the main mechanism for improving the strength and toughness of the KNO3-based salt core.

Partially compacted polypropylene glass fiber non-woven composite: Influence of processing, porosity and fiber length on mechanical properties and modeling

Non-woven materials feature unique properties that allow them to be used in different applications. In this study, polypropylene and glass fibers were commingled and pressed to obtain partially compacted composites. Fiber content, fiber length and processing parameters were modified to investigate their influence on the final properties of the composites. These were characterized by scanning electron microscopy (SEM), tensile and porosity measurements as well as fiber content and length distribution analysis. The stiffness of the composites increase linearly with increasing glass fiber content, from 1.6 GPa to 4.8 GPa. Longer fibers can be found in the composites with higher fiber contents. Applied pressure and number of stacked layers were found significant factors for the limitation of void content. Fiber-matrix interactions were improved with the addition of maleic anhydride grafted polypropylene, increasing the tensile properties in the low porosity range. A suitable model was found for the prediction of mechanical properties.

Stress‐life prediction of 25°C polypropylene materials based on calibration of Zhurkov fatigue life model

AbstractIn this study, to evaluate the chemical and mechanical properties of polypropylene (PP), activation‐energy and tensile tests were performed at room temperature (25°C) on pure PP and PP reinforced with glass fibre (GF). To improve the prediction accuracy of the fatigue life, three models based on the calibration of the Zhurkov model were proposed: a regression model, modified strain‐rate model and lethargy coefficient‐based model. Based on the experimental data analysis and statistical assessment results, we proposed a modified strain‐rate model that satisfies the dependency of the physical parameters and is congruent with the predicted fatigue life data. The experimental data and modified strain‐rate model were compared with the direct cyclic analysis results. The tendency of the frequency factor as a correction parameter in the modified strain‐rate model corresponded to the experimental activation energy and the increasing GF content.

Influence of different fiber types on properties of biocemented calcareous sand

Within recent years, microbial induced calcium carbonate precipitation (MICP) technology has been widely applied to ground improvement. The addition of fiber has a great improvement on properties of biocemented sand. This paper studied the influence of three fiber types on properties of biocemented calcareous sand by using MICP technology and discovered the influence mechanism of three fiber types on biocemented calcareous sand. Unconfined compressive strength (UCS) test, tensile strength test, and calcium carbonate content were carried to estimate properties of biocemented calcareous sand. The microstructures of biocemented calcareous sand with fibers and surface of three fiber types were observed under the scanning electron microscope. The test results showed that the ductility, the bridging role, and calcium carbonate content of biocemented calcareous sand with carbon fiber were better, followed by basalt fiber and glass fiber. The UCS, tensile strength, and calcium carbonate content of biocemented calcareous sand increased with the increasing fiber content. The optimum fiber content of biocemented calcareous sand was found to be 1%. Compared with biocemented calcareous sand without fiber, the unconfined compressive strength of biocemented calcareous sand at optimum glass fiber, basalt fiber, and carbon fiber content increased by 458%, 784%, and 1133%, respectively. Meanwhile, the tensile strength of biocemented calcareous sand at optimum basalt fiber, glass fiber, and carbon fiber content increased by 115%, 129%, and 317%, respectively. Therefore, the properties of biocemented calcareous sand with carbon fiber are better than basalt fiber and glass fiber.

Mechanical properties of glass fibre reinforced soil and its application as subgrade reinforcement

The study examined the use of two different types of glass fibres – Alkali Resistant (AR) Glass Fibre and Electronic Grade (E) Glass Fibre as reinforcement in soils to improve its strength. Glass fibre reinforcement causes a marginal change in the plastic nature and compaction behaviour of the reinforced soil. Also, the addition of fibres renders the soil less sensitive to moisture changes. Fibre inclusion promotes ductile behaviour of reinforced soil. Unreinforced soil fails with distinct shear plane while reinforced soil shows multi-shear failure and bulging with a network of minor cracks bridged with fibres. The results of this study show that random inclusion of fibres improve the unconfined compressive strength of the reinforced soil and it’s energy absorption capacity. The optimum glass fibre content is observed to be 0.75% for both AR glass fibre and E glass fibre. AR glass fibre performs better than E glass fibre for all proportions of fibre inclusion investigated.