Types Of Glass Fibers Research Articles

Fabrication and compression performance of continuous fiber Octet-truss lattice sandwich structure

Octet-truss is a three-dimensional lattice structure with light configuration and multi-function characteristics. In order to analyze and verify its compression resistance, a method of preparing Octet-truss lattice sandwich panel with continuous fiber was proposed. A set of Octet-truss structure molding tools was designed by this method. Different types of glass fiber and Kevlar fiber specimens were prepared by spatial weaving method and resin curing process, and the axial compression test was carried out. The experimental results show that the mechanical properties of different materials and different sizes of sandwich panels prepared by this method are stable, and the reliability of the preparation process is verified, Combined with the experimental process and electron microscope images, the main failure mode of glass fiber samples is fracture of the struts near the nodes induced by fiber microbuckling, while the Kevlar fiber samples failed by the Euler buckling of the struts.

Experimental analysis on tensile strengthening properties of steel and glass fiber reinforced inorganic matrix composites

The fiber-reinforced inorganic matrix (FRIM) composite is a new type of composite, which has many economical and performance advantages. Beside the direct shear and bending tests, the tensile tests form an integral part in determining the mechanical properties of these composites. In this paper, to understand the tensile behavior of the FRIM composites, some strip specimens of the composites were tested which were clamped at the both ends, and the strains were measured using the extensometers installed at the middle of each strip. The inorganic matrix composites studied in this paper were constructed using two types of steel and glass fibers together with two different types of inorganic lime and geopolymer mortars. The results of direct tensile tests showed that the inorganic geopolymer mortars had the higher potential to increase the tensile load bearing of the specimens compared with the lime mortars. In addition, in most cases, the maximum values of stress, strain and the stiffness at the final stage of response in the tensile tests of composites were consistent with the results reported from the tensile test of textile fibers without the mortar. Moreover, clamping specimens by applying sufficient compressive force prevents slipping of fibers within the surrounding mortar.

Filter life comparison of different levels of nanofiber coated cleanable‐surface filter for gas turbine

AbstractHigh‐efficiency air filtration is a basic requirement for the most cost‐effective operation of high‐efficiency gas turbines. The filtration system protects the gas turbine from damaging debris. In gas turbine/dust collector applications, higher efficiency filtration could be achieved with nanofibers, which provide higher equipment protection than traditional media. With a nanofiber performance filter layer, the dust accumulates on the surface of the filtration media rather than within the media and could be cleaned off easily with a back pulse resulting in long filter life and a low‐operating pressure drop. In this study five type of gas tribune nanofiber coated corrugated cellulose/synthetic filter media were developed. Nanofiber coating was adjusted for five filtration efficiency level, 50 ≤ E < 60, 60 ≤ E < 70, 70 ≤ E < 85, 85 ≤ E < 95 and 95 ≤ E, pore size and filter‐life of the developed media were evaluated. One of the developed nanofiber coated media was also compared with two other commercial nanofiber coated gas tribune filter media, a glass fiber type filter media and a commercial fine fiber gas tribune filter media. It was seen that, with decreasing penetration levels due to nanofiber coating level, initial 30 cycle durations of filter life evaluation could reach about 229.9 to 250.7 min. Highest final cycle duration of 188.7 min belonged to cellulose/synthetic blend corrugated filter media with penetration of 13.66%. Nanofiber based surface filter media was cleaned up better than fine fiber media and final 30 cycle sequences were significantly higher. Surface of the nanofiber coated media was smoother when compared to fine fiber media and during the initial and final cycle test dust could not penetrate inside and could not hang to this smooth surface. So, with back pulse cleaning cake releasing have performed easily. It was also seen that, for higher filter life nanofiber coating should be uniform and robust to back pulse cleaning.

Visual inspection and mechanical testing of fly ash-based fibrous geopolymer composites under freeze-thaw cycles

In this research, an experimental study was conducted to evaluate freeze–thaw behaviour of fiber reinforced geopolymer mortars. To build up an extensive experimental program, three different fiber types of basalt fiber (BF), steel fiber (SF), and glass fiber (GF) with two different lengths, three fiber volume fractions of 0.4, 0.8, and 1.2%, and three freeze–thaw cycles of 100, 200, and 300 were chosen as the experimental parameters. Here, the solid binding component was the fly ash with a fixed dosage of 550 kg/m3 while the alkaline activators were Na2SiO3 and NaOH solutions. A fixed alkaline activator-to-binding material (solid binding component) ratio of 0.5 was assigned. In total, 13 different fly ash-based geopolymer mixtures were designed. Based on the results of the experimental program it was found out that the workability of the geopolymer mortars was adversely affected by the fiber addition. A continuous increase in both compressive and flexural strengths was achieved when the volume fraction of the BF and SF type fibers were increased. Another critical finding is that utilization the fiber decreased the damage of the freeze–thaw cycles. Therefore, it was proved that the use of fiber can be an effective way to increase the durability of the geopolymer mortar against the freeze–thaw cycles. The mortars manufactured in this study maintained their integrity even after being subjected to the 300 freeze–thaw cycles. In order to provide a better assessment, the experimental program was supported by visual inspection of the specimens at each 100 freeze–thaw cycles.

Orientation and Type of Non-dental Glass Fiber Towards The Flexural of Fiber Reinforced Composite

Introduction : Non-dental glass fiber can used as alternative dental glass fiber. Flexural strength to withstand masticatory loads that influenced by various factors, including the orientation and type of fiber used. Purpose : The purpose of this study was to see the effect of orientation and type of non-dental glass fiber on flexural strength. Method : The research method used FRC samples measuring 65 x 10 x 2,5 mm which were reinforced with non-dental glass fiber mats, roving, woven roving, and dental glass fiber roving. Non-dental glass fiber mats and woven roving was cut according to the length and width of the sample, while the non-dental glass fiber roving was weighed according to the weigh tof 4 sheets of dental glass fiber roving to meet the sample mold zone. Result : Glass fiber placed in the tension position in the sample mold. The flexural strength was tested using universal testing machine. This study indicate that the type of glass fiber doesn’t have a significant effect on the flexural strength of FRC with reinforced non dental glass fiber and dental glass fiber. Conclusion : The orientation of non-dental glass fiber roving as reinforcement of FRC has greater flexural strength than non-dental glass fiber with mats and woven roving orientation.

Low velocity impact performance of fiber-reinforced polymer impregnated with shear thickening fluid

In this study, the mechanical performance of fiber-reinforced polymer (FRP) impregnated with shear thickening fluid (STF) under low-velocity impact was investigated. Three types of FRPs, with basalt (BFRP), carbon (CFRP), and glass (GFRP) fibers were prepared and 20 wt% STF was impregnated into these FRPs to develop FRP composite materials. The resistive force and energy dissipation of STF-impregnated FRP (FRP-STF) specimens and corresponding neat FRP specimens were evaluated using a drop hammer test. The test results demonstrate that the impregnation of the STF can effectively enhance the impact resistance performance of the three FRPs. Nevertheless, the enhancing effect and mechanism are different for different FRP types. For the BFRP and CFRP, the STF only improves their mechanical performance, while for the GFRP, the STF changes its mechanical mechanism. In terms of maximum enhancement resistive force, the STF has a significant effect on the CFRP, with a 78.0% increase compared to neat CFRP. In addition, the GFRP-STF shows excellent energy dissipation performance; the energy absorbability is increased to 90.7%, an increase of 119% compared to neat GFRP.

Light transmission and bond strength of glass fiber posts submitted to different surface treatments

Statement of problemLight transmitted deep into the root canal is an important parameter to increase bonding of the cement to the post and dentin. Glass fiber posts seem to be an option to increase transmitted light, but literature on the light transmittance profile and power transmission to deep canal regions is lacking. PurposeThe purpose of this in vitro study was to evaluate light delivered by 2 types of fiberglass posts submitted to different surface treatments and to evaluate the bond strength. Material and methodsWhiteposts and Superposts were allocated to 4 groups: no surface treatment, surface treatment with 24% hydrogen peroxide, surface treatment with silane, and surface treatment with 24% hydrogen peroxide plus silane. The total light transmitted by the posts was measured by using an integrating sphere to collect the diffuse light. The light profile that was laterally delivered to the post was measured with a power detector equipped with an optical fiber probe. The bond strength was measured with the push-out test. Scanning electron microscopy was used to evaluate the surface treatments. The light transmission data were analyzed by using a generalized linear model and the Bonferroni test and the bond strength values were evaluated by using ANOVA and the Tukey test (α=.05). ResultsThe cervical third presented the highest transmission (74.1% for Whiteposts and 74.6% for Superposts), followed by the middle (20.9% for Whiteposts and 20.4% for Superposts) and apical (5.0% for both Whiteposts and Superposts) thirds. Superposts led to higher bond strength than Whiteposts (9.73 ±5.89 and 8.48 ±4.99 MPa, respectively). Surface treatment with silane and hydrogen peroxide plus silane afforded similar bond strength (11.4 ±6.4 and 10.7 ±5.6 MPa, respectively), which was higher as compared with the bond strength obtained after surface treatment with hydrogen peroxide. For both post types, the bond strength decreased from the cervical (12.2 ±6.0 MPa) to the middle (9.7 ±5.0 MPa) and apical (6.5 ±3.6 MPa) thirds. ConclusionsLight transmission and bond strength decreased from the cervical to the apical third. Surface treatment impacted bond strength; light transmission through Whiteposts was slightly higher than light transmission through Superposts.

Mechanical Damage Assessment of GFRP Rebars with Different Resins due to Hydrothermal Aging

Abstract This study investigates the effect of hydrothermal aging on the properties of glass fiber reinforced polymer (GFRP) rebars manufactured with isophthalic polyester or vinylester resin and glass fiber type E. The GFRP rebars were immersed in an alkaline solution (pH 12.6) for 1000 h at different temperatures (23 and 60 oC), and their deterioration was evaluated based on microstructural and chemical changes (using SEM, DSC, XRF, and FTIR techniques), moisture absorption, and variation in mechanical properties. The results indicated an increase in the presence of voids and water absorption of the rebars with accelerated aging, with a reduction in the glass transition temperature of the resin and alteration of the chemical composition of the glass fiber. The comparison between the experimental results indicates that the rebars with matrix in vinylester resin present greater chemical resistance than the rebars with a polyester matrix. The degradation of the rebar also resulted in a reduction of approximately 6% in the tensile strength of the rebar and 2% in the modulus of elasticity. Using the damage model, it was possible to identify that the reduction in mechanical strength was associated with the simultaneous degradation of the resin and glass fiber due to the alkaline attack.

Do customized fiberglass posts influence the bond interface in different regions of intraradicular dentin?

This study evaluated the push-out bond strength of customized glass fiber posts in different regions of post space (cervical, middle and apical) submitted to mechanical cycling. Forty single-rooted human premolar teeth were submitted to endodontic treatment and divided into four groups, according to the type of fiberglass posts installed: customized or non-customized posts. Half of the samples were submitted to 1,200,000 mechanical cycles. Samples sections of approximately 1.3 mm thickness were obtained from each regional third and the samples were subjected to push-out bond test. Data were analyzed by two-way repeated measures ANOVA and Tukey's test (p = 0.05). There was no statistically significant difference between customized and non-customized fiberglass posts at the cervical region, regardless if the mechanical cycling was performed. (p = 0.18). In the middle third, the highest value of bond strength was observed in the non-customized group without mechanical cycling (12.90 ± 6.88 MPa), but it was not significantly different from the respective aged group (7.58 ± 4.72 MPa) (p > 0.05). Similar results observed in the apical region, where lower values were found for the customized groups. For customized fiberglass posts, the cervical region showed higher values of bond strength compared to the middle and apical thirds (p < 0.05) with or without mechanical cycling. The customization of fiberglass posts is not an essential clinical procedure since it does not improve the bond strength of fiberglass posts to dentin, independent of the mechanical cycling procedure.

Comparative study on flexural behavior of corroded RC beams strengthening using near surface mounted GFRP elements

In this study, corroded reinforced beam specimens failing in bending were strengthened using near surface mounted (NSM) technique and evaluated. Two types of glass fiber reinforced polymer (bar, mat) were investigated for the strengthening materials. A simulated corrosion rate of 25% was considered in the study. The maximum recorded load of the strengthened beams with GFRP bars showed enhancement in the ultimate strength which reached 89% of the undamaged control beam strength. While using of GFRP mat for strengthening the corroded beams increased only the ductility but had negligible effect on the improvement of ultimate strength. The results indicated that using near surface mounted technique prevents the occurrence of de-bonding failure which results in an enhancement in the crack load and failure load of the tested beams.

A performance analysis of conventional reinforcement methods for “exotic” building stones according to the current technical requirements

Standard methods for dimensioning stone applications have increased their importance in new construction projects. Natural stones are unique in their structure, and thus, one would expect larger differences in properties when compared with other synthetic competitors. To pursue the objective of meeting technical requirements, very heterogeneous stone slabs (such as exotic materials with high market value) are usually reinforced using epoxy resins embedded in low-density glassfiber, a process showing low mechanical efficiency. In the present work, four types of thermoset resins and two types of glass fibers were used to reinforce a pegmatitic stone from Brazil, in order to determine the flexural strength and compare it to a sound sample. Results after 4-point bending tests show that relative stiffness is not affected by the use of glassfiber solutions, and the standard dimensioning requirements are only attained in accordance to mechanical strength when high-density glassfiber systems are employed in the surfaces submitted to tensile stresses under a flexural loading. This work allows concluding that, when using such exotic and highly heterogeneous stones, conventional reinforcement methods are not adequate, especially for more demanding cladding and flooring applications.

Mechanical properties of nanoclay-filled kenaf and hybrid glass/kenaf fiber composites

Kenaf is a natural fiber that can be used as an alternative reinforcement material due to its excellent properties such as low density and high strength. In this study, kenaf composites were developed by hybridizing with glass fiber and modified with nanoclay to enhance its mechanical properties. The woven type of glass fiber was placed on top and bottom of the kenaf composite. Three different percentages of nanoclay contents, i.e. 1 wt%, 3 wt%, and 5 wt% were modified with epoxy resin to fabricate nanoclay-filled Kenaf (KFRP) and nanoclay-filled hybrid Glass/Kenaf (GKFRP) composites. The composites were prepared by dispersing nanoclay into epoxy using the three-roll mill machine, and the kenaf fiber was wound using filament winding machine. The flexural test and tensile test in longitudinal (0°) and transverse (90°) fiber direction were performed to study the effect of hybridizing glass fiber and adding nanoclay into KFRP composites. The results show that hybridization of kenaf fiber with glass fiber enhanced flexural and tensile properties in both fiber directions. The addition of 1 wt% and 3 wt% nanoclay also improve the tensile and flexural properties of KFRP composites; however, the addition of 5 wt% nanoclay reduces the mechanical performance of composites.

Modeling for bond-constitutive relationships of FRP rebars to concrete matrix

45 pullout tests on three types of Glass Fiber Reinforced Polymer (GFRP) reinforcing bars (rebars) and the surrounding concrete have been conducted in this paper. The test shows that the bond strength of the indented and helicoidal tow rebars is the highest, and that of the indented and sandblasted rebars is the lowest. Pullout failure occurs in most of the specimens. An analytical model of bond-slip characteristic is proposed according to the experimental data, in which the ascending branch is expressed by the Weibull curve equation and the descending branch is linearly simplified. The accuracy of the proposed model is evidenced by the curve-fitting degree with respect to the well-known models and existing experimental results.

Highly Insulated Wall Systems with Exterior Insulation of Polyisocyanurate under Different Facer Materials: Material Characterization and Long-Term Hygrothermal Performance Assessment.

The application of exterior insulation in both new construction and retrofits is a common practice to enhance the energy efficiency of buildings. In addition to increased thermal performance, the rigid insulation can serve to keep the sheathing board warm and serve as a water-resistive barrier to keep moisture-related problems due to condensation and wind-driven rain. Polyisocyanurate (PIR) rigid boards have a higher thermal resistance in comparison to other commonly used exterior insulation boards. However, because of its perceived lower permeance, its use as exterior insulation is not very common. In this study, the hygrothermal property of PIR boards with different facer types and thicknesses is characterized. The material data obtained through experimental test and extrapolation is used in a long term hygrothermal performance assessment of a wood frame wall with PIR boards as exterior insulation. Results show that PIR with no facer has the smallest accumulated moisture on the sheathing board in comparison to other insulation boards. Walls with a bigger thickness of exterior insulation perform better when no vapor barrier is used. The PIR exterior insulation supports the moisture control strategy well in colder climates in perfect wall scenarios, where there is no air leakage and moisture intrusion. In cases where there is trapped moisture, the sheathing board has a higher moisture content with PIR boards with both aluminum or fiberglass type facers. An innovative facer material development for PIR boards can help efforts targeting improved energy-efficient and durable wall systems.

Comparative evaluation of flexural strength and modulus of denture base resin with mesh and stick type glass fiber reinforcement

Comparative evaluation of flexural strength and modulus of denture base resin with mesh and stick type glass fiber reinforcement

FORMATION OF RESIDUAL STRENGTH OF STRUCTURAL FIBER IN CONDITIONS AFTER FIRE

The article presents the results of dynamic mechanical tests of fiberglass specimens under the conditions of the effects of intense heating on them, which corresponded to the development of a slowly developing fire. It is established that with intensive heating at the initial stage of fire, the considered type of fiberglass loses its initial strength, but then, upon cooling, acquires increased rigidity, while maintaining sufficient integrity and relative structural functionality. In our view, this increase is due to the significant increase in the carbon fraction in the polymer binder with the formation of a more densely packed structure due to the formation of sites with associated aromatic fragments. At the same time, the drop in strength occurs due to the formation of a sufficient number of voids (pores and cracks), the occurrence of which is characteristic of materials of organic nature (plastics based on synthetic polymers) in the process of thermal oxidation destruction under intense heating. It is established that the degree of conservation of the load-bearing strength of the fiberglass can be arranged in the following order: bending&gt; stretching&gt; compression. This behavior of the material indicates the use of additional structural measures when using it as the supporting elements of construction and technological structures. The determining factor in the observed modification of the composite is the extent of the passage of the pyrolytic transformations of the polymer bond, which can indirectly be characterized by a change in the dynamic mechanical properties of the material under intense heating. The main role is played by the binder component - the epoxidized naphthalene type oligomer, whose function is reduced to the ability to play a role in the volume of the polymer matrix of coke formation germs. The above composition of components and the method of its production allows to develop polymeric composite materials without the use of additional components - flame retardants (retardants), which complicate the technology of obtaining the composite and in some cases reduce its initial physical and mechanical properties. Keywords: fiberglass, residual strength, fire aftereffect, dynamic mechanical tests, epoxidised dinaftol

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.

Axial mechanical properties of concrete-filled GFRP tubular hollow composite columns

In this paper, a new type of concrete-filled Glass Fiber Reinforced Polymer (GFRP) tubular hollow composite column is tested and analyzed by finite element analysis. The axial pressure test of 27 concrete-filled GFRP tubular hollow composite columns is made to investigate the compressive properties of the specimens, including the failure mode, ultimate bearing capacity under axial compression, load-strain relationship and load-displacement relationship. The effects of the three parameters of hollow ratio, diameter-to-thickness ratio of GFRP tube and concrete strength grade on the axial compressive properties of concrete-filled GFRP tubular hollow composite columns are studied, and some key principles of designing concrete-filled GFRP tubular hollow composite columns are presented. The parameters of hollow ratio, diameter-to-thickness ratio of GFRP tube, and concrete strength grade are analyzed by using the verified finite element model. An ultimate bearing capacity adjustment coefficient is proposed, which takes into consideration the influence of hollow sections. A recommended formula is given for the axial bearing capacity of concrete-filled GFRP tubular hollow composite columns.

Shear Behavior of Concrete Beams Reinforced With A New Type of Glass Fiber Reinforced Polymer Reinforcement: Experimental Study.

The article presents experimental tests of a new type of composite bar that has been used as shear reinforcement for concrete beams. In the case of shearing concrete beams reinforced with steel stirrups, according to the theory of plasticity, the plastic deformation of stirrups and stress redistribution in stirrups cut by a diagonal crack are permitted. Tensile composite reinforcement is characterized by linear-elastic behavior throughout the entire strength range. The most popular type of shear reinforcement is closed frame stirrups, and this type of Fiber Reinforced Polymer (FRP) shear reinforcement was the subject of research by other authors. In the case of FRP stirrups, rupture occurs rapidly without the shear reinforcement being able to redistribute stress. An attempt was made to introduce a quasi-plastic character into the mechanisms transferring shear by appropriately shaping the shear reinforcement. Experimental material tests covered the determination of the strength and deformability of straight Glass Fiber Reinforced Polymer (GFRP) bars and GFRP headed bars. Experimental studies of shear reinforced beams with GFRP stirrups and GFRP headed bars were carried out. This allowed a direct comparison of the shear behavior of beams reinforced with standard GFRP stirrups and a new type of shear reinforcement: GFRP headed bars. Experimental studies demonstrated that GFRP headed bars could be used as shear reinforcement in concrete beams. Unlike GFRP stirrups, these bars allow stress redistribution in bars cut by a diagonal crack.

Quasi-Static Indentation Response of Galvanized Iron Toughened Glass Fiber/Epoxy Laminates

This paper is aimed to study the quasi-static indentation response of fiber metal laminates (FMLs) that are made of various arrangement of galvanized iron (GI) alloy thin sheet, glass fibre and epoxy polymer. Unidirectional and woven types of glass fiber/epoxy pre-impregnated laminates and three different thickness of GI thin sheet, i.e. 0.5, 1.0 and 2.0 mm, were used to produce FML systems using combination of hand layup and hot press methods. The FML systems were coded as UGFRP, UGFML 1/2-2, UGFML 2/3-1, UGFML 4/5-0.5, WGFRP, WGFML 1/2-2, WGFML 2/3-1, WGFML 4/5-0.5 according to their types of glass fibers, thickness of GI and stacking sequence. Quasi-static indentation (QSI) tests were performed according to ASTM D6264 using hemispherical crosshead at 5 mm/min speed rate. It was found that both unidirectional and woven systems of FML 1/2-2 exhibited the highest energy absorption capacity, with enhancement of 28 times and 11 times more than UGFRP and WGFRP composite, respectively. At maximum compression, FML 2/3-1 displayed the highest ultimate load, while FML 1/2-2 displayed the highest displacement for both fiber systems. Damage area inspection revealed severe matrix crack, fiber fracture and delamination upon penetration and perforation.