Glass Fiber Reinforced Polyester Resin Research Articles

FLEXURAL PERFORMANCE OF RC BEAMS BONDED WITH UV-GFRPR SHEETS

This study presents the flexural performance of reinforced concrete (RC) beams externally bonded with UV-curable glass fiber reinforced polyester resin (UV-GFRPR) sheets onto their soffit surface. UV-GFRPR sheets can be cured by UV irradiation. The UV-GFRPR sheets after hardening have about one-seventh of the yield strength of normal steel (SS400), which is lower than FRP sheets such as carbon, aramid, and glass fibers. However, the UV-GFRPR sheets are easily attached to the surfaces of substrates for repair and preventive maintenance and have excellent durability with impermeability of moisture and corrosion factors. The aims of this study are to assess the flexural performance and the strengthening effect of RC beams bonded with two and three laminated layers of the UV-GFRPR sheets in four-point bending tests. The test results showed that the ultimate load-carrying capacities of the specimens with two and three laminated layers were 1.13 and 1.37 times higher than that of the control beam. The RC beams with the UV-GFRPR sheets failed in bending due to rupture of the UV-GFRPR sheets. The load-carrying capacity and the flexural performance were also predicted using the cross-sectional analysis.

Development of hybrid composite by integrating functionalized multi-walled carbon nanotubes (f-MWCNTs) with glass fiber reinforced polyester composite.

The current work presents the development of hybrid glass fiber reinforced polyester resin (GFRPs) composite. The composite integrates functionalized carbon nanotubes (f-MWCNTs) with glass fiber (GF) using polyester resin as a media. Hand lay-up method was adopted to prepare GFRPs samples in the form of rectangular sheets. Morphological characteristics of the GFRPs were investigated through scanning electron microscopy (SEM), to analyze the f-MWCNTs distribution and agglomeration of the developed composite's surface due to varying concentrations from 0.0 to 0.5 wt.%. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) were performed to confirm the presence of f-MWCNTs in the developed GFRPs. Sample with 0.4 wt. % f-MWCNTs showed the highest tensile strength and impact energy of 79 MPa, indicating a 31.66% improvement and 1.6 Nm with 77% improvement, respectively as compared to the control sample (0.wt.% f-MWCNT). The same sample also showed the thermal stability till 390 °C as measured through thermogravimetric analysis (TGA). Deposition of extra 10 layers initially increased the composite strength from 40 MPa to 128 MPa, however further increase in layers to 15 resulted decrease in strength to 100 MPa due to the poor interaction between the polyester resin and GF. The addition of f-MWCNTs in the composite effectively strengthens the interfacial bonding, which significantly improved the tensile and impact strength of the composite, making it tougher and thermally stable. However, further increase in the concentration of f-MWCNTs degraded the mechanical properties of developed composite such as compressive strength because of agglomeration of these nanoparticles and void formation in the composite.

Flexural analysis of hemp, kenaf and glass fibre-reinforced polyester resin

Abstract Natural fibres have a high potential to replace synthetic fibres such as glass in a variety of applications. However, natural fibre-reinforced composites still have some limitations with respect to the mechanical performance especially in high load bearing capabilities. The hybridization of natural fibres with synthetic fibres in the same matrix has proven to create a balancing effect and enhanced the composites performance. Besides that, fibre architectures that include fibres continuity, fibres orientation, fibres arrangement and fibres interlocking are also considered to enhance the overall performance of the composites. In this study, the hemp mat, kenaf mat and glass chopped strand mat were hybridised with woven glass fibres, respectively in polyester resin to form 12 systems of the composites. The hybridization effects of different fibre core material, fibre core thickness and fibre arrangement on flexural response were investigated according to ASTM D7264. The results indicated that hybrid CSM glass/woven glass composite showed the highest flexural strength and modulus compared to hemp/woven glass and kenaf/woven glass composites, with about 377.15 ± 48.41 MPa and 16.74 ± 7.15 GPa. Among natural fibres, kenaf fibre (2WG/K/2WG) composite showed better flexural properties compared to hemp fibre (2WG/H/2WG) composite. 2WG/2G/2WG composites with two plies of CSM glass showed maximum flexural properties. As for hemp/woven glass and kenaf/glass hybrid composites, the flexural properties reached a maximum value in system arrangement of (2:1:2) but it reduced in the system arrangement of (2:2:2) and (2:4:2). On the evaluation effect of fibre arrangement, hemp, kenaf and glass mat used as core (arrange in the middle; (2:2:2)) showed higher flexural properties as compared to the use as skin (arrange in outer; (1:4:1)). (2WG/2K/2WG) showed better flexural properties than (2WG/2H/2WG) as the core, while (H/4WG/H) showed better flexural properties than (K/4WG/K) as skin.

TENSILE BEHAVIOR AND STRENGTH OF STEEL PLATE BONDED WITH UV-CURABLE GLASS FIBER REINFORCED POLYESTER RESIN SHEET ON BOTH SIDES

Steel structures in social infrastructures often undergo corrosion and the thickness of these steel plates decreases. Then, the strength of steel structures decreases according to the residual plate thickness. Applications of a steel plate attaching method and a fiber reinforced polymer/plastic (FRP) bonding method are effective for repair and strengthening for these steel structures. In this study, UV-curable glass fiber reinforced polyester resin (UV-GFRPR) sheet was focused instead of FRPs. The aims of this study are to confirm repair and strengthening effects of the UV-GFRPR sheet bonded on both sides of steel plate. The UVGFRPR sheet consists of a polyester resin and chopped glass fibers and is hardened by radiation of UV source for a certain time. The tensile behavior and strength of steel plate bonded with UV-GFRPR sheets were assessed under axial tensile load. After that, the tensile behavior and strength of specimens were numerically estimated from each stress-strain curve of UV-GFRPR and steel modeled by using Menegotto-Pinto model. Furthermore, nonlinear finite element analysis (FEA) taking into account of the properties of bond layers was carried out to compare the numerical results. From the test results, the yield and ultimate strengths of specimens increased linearly according to the number of laminated layers of UV-GFRPR. Both results of the numerical calculation and the FEA agreed well with the test results. It is concluded that the numerical calculation without the contribution of bond layers can estimate the tensile behavior and strength of steel plate bonded with UVGFRPR on both sides

Low-cost small-scale distillation column: assessment of polymeric materials on its economic, chemical, mechanical, and environmental performance

Distillation columns can have high economic impact on small-scale ethanol production because their capital cost and, therefore, a lower investment in this equipment may turn it more feasible. The present work aims to assess the substitution of stainless steel and borosilicate glass by polymeric materials in the manufacturing of distillation columns. A decision tree was proposed, considering chemical, mechanical, thermal, and economic aspects. In addition, a life cycle assessment (LCA) was used to evaluate potential reduction on environmental impacts from columns manufactured with polymeric material. Tests were performed to investigate chemical resistance, including determination of the degree of swelling and characterizations by X-ray diffraction, Fourier-transform infrared, and exploratory scanning calorimetry. Mechanical properties were evaluated by 3-point bending tests. Polymeric materials were selected due to their lower cost in comparison with stainless steel, e.g., polypropylene, high-density polyethylene, and glass fiber-reinforced polyester resin. Results showed satisfactory chemical and mechanical resistance of these three polymers after contact with ethanol, and a 68% reduction in capital cost related to a manufacturing of distillation column with polypropylene. LCA results showed that replacing stainless steel and borosilicate glass by polypropylene in distillation column manufacturing would result in lower environmental impacts in all impact categories considered. A reduction in CO2eq emissions of 85% and 59% was observed when polypropylene replaced stainless steel and borosilicate glass, respectively.

Semi-active vibration control of MRF core PMC cantilever sandwich beams: Experimental study

The semi-active vibration control of sandwich beams made of chopped strand mat glass fiber reinforced polyester resin polymer matrix composite (PMC) and magnetorheological fluid (MRF) core were experimentally investigated in this study. Two-, four- and six-layered glass fiber reinforced polyester resin polymer matrix composites were prepared using the hand-layup technique. The magnetorheological fluid was prepared in-house with 30% volume of carbonyl iron powder and 70% volume of silicone oil. Nine cantilever sandwich beams of varying thicknesses of the top and bottom layers glass fiber reinforced polyester resin polymer matrix composite beams and middle magnetorheological fluid core were prepared. The magnetorheological fluid core was activated with a non-homogeneous magnetic field using permanent magnets. The first three modes, natural frequencies and damping ratios of the glass fiber reinforced polyester resin polymer matrix composite-magnetorheological fluid core sandwich beams were determined through free vibration analysis using DEWESoft modal analysis software. The amplitude frequency response of the glass fiber reinforced polyester resin polymer matrix composite-magnetorheological fluid core sandwich beams through forced vibration analysis was determined using LabVIEW. The effect of various parameters such as magnetic flux density, thickness of glass fiber reinforced polyester resin polymer matrix composite layers and magnetorheological fluid core layer on the natural frequencies, damping ratio and vibration amplitude suppressions of the glass fiber reinforced polyester resin polymer matrix composite-magnetorheological fluid core sandwich beams was investigated. Based on the results obtained, 2 mm thickness top and bottom layers glass fiber reinforced polyester resin polymer matrix composite and 5 mm thickness magnetorheological fluid core sample have achieved a high shift in increased natural frequency, damping ratio and vibration amplitude suppression under the influence of magnetic flux density.

Mechanical properties of glass fiber reinforced polyester resin for use as the wall of the Acehnese boat ‘Thep-Thep’

Fiber composites are very commonly used for engineering applications nowadays. The product has begun to enter the field of boat and ship manufacturing. An Acehnese traditional boat known as thep-thep, which has a capacity of 3 GT, is a means of transportation used in Aceh waters. This study focuses on the mechanical properties of the material used for the structure and walls of the thep-thep. Specimens are made from materials with E-glass fiber reinforced polyester resin. The hand lay-up method is used in the process of making the specimens, applied with a pressure of 25 kg/cm2 for 24 hours. This study aimed to obtain higher mechanical properties using composites of layers of chopped strand mat (CSM) fibers and woven roving mat (WRM) fibers with a ratio of 1:0, 1:1, and 2:1, respectively. Tensile testing is done using the ASTM D3039-00 standard. From the tensile test data obtained from several different composite ratios, the highest composite is found at around 49.2 MPa. An increase in the number of fiber layers makes the fiber composites more reliable to be the raw material in the making of the Acehnese boat thep-thep.

Effect of variation of low cost reinforcement on natural frequency Of polyester resin glass fibre hybrid composites

Fiber reinforced polymer matrix composites are the class of composite materials finding vast applications in automotive, aircraft, defence, sports and appliance industries. Resonance caused by vibrating mechanical system results failure of machine components but if somehow natural frequency is increased or decreased from the range of operating machine member resonance phenomenon could be avoided. Hybrid composites specimen were fabricated using glass fiber reinforced polyester resin matrix with varying of fly ash (weight 0%, 6%, 12%, 18%, 24%, 30%) respectively fabricated using hand lay-up method. Impact hammer tests were done on these rectangular thin plate specimens. Test results from Impact hammer test was analysed by using “Smart office analyser” to find out the natural frequency for each sample. The result revealed that the natural frequency increases up to 12 weight% of fly ash addition and then decreases. The addition of 10 to 12 weight% of fly ash gives the maximum natural frequency and component made from this composition can be used on system which is vibrating below this range of frequency.

Modeling and experimental studies of thermal degradation of glass fiber reinforced polymer composites

ABSTRACTThis study developed a numerical model that simulated the degradation rate and temperature profiles of a glass fiber reinforced polyester resin composite exposed to a constant heat flux in a cone calorimeter. By considering the thermal properties of the composite structure consisting of alternating layers of pure polymer and polymer‐infused glass fiber mat, the numerical model seeks to reproduce the experimental data from the cone calorimeter test. The final results are achieved through adding a simulated heat flux from the pilot ignition of the degraded gas of the polyester resin. The good agreement between the predicted and experimental results suggests that such models are cost‐saving tools over the process of designing and manufacturing of composites for meeting fire safety requirements, without having to fabricate many samples for testing and final selection. Copyright © 2013 John Wiley & Sons, Ltd.

Mode I Fracture Toughness of Banana Fiber and Glass Fiber Reinforced Composites

Although fiber-reinforced polymers (FRP) have until now been largely applied to various fields of engineering, these materials have also been used in many technical applications, especially where high strength and stiffness are required, but with low component weight. Among various natural fibers, banana fiber is of particular interest in that its composites have high tensile strength, high tensile modulus, and low elongation at break beside its low cost and eases of availability. In this study, banana fiber and glass fiber reinforced polyester Resin composites were prepared using hand lay up technique . Experiments are conducted to compare and to find the effect of fiber volume fraction on mode I fracture toughness of both composites.

Thermal decomposition and fire behavior of glass fiber–reinforced polyester resin composites containing phosphate-based fire-retardant additives

The thermal degradation and the fire behavior of a polyester resin containing phosphate-based fire-retardant additives and its corresponding glass fiber composites were investigated. An unsaturated commercial polyester resin was modified by the addition of three phosphate-based fire retardants: ammonium polyphosphate, silane-coated ammonium polyphosphate, and melamine pyrophosphate, at 35% w/w. The effects of the fire retardants on resin thermal decomposition and small-scale fire behavior were studied using dynamic thermogravimetric tests at different heating rates and microcalorimetric measurements according to ASTM D7309-07. Different modes of degradation with different activation energy levels for the neat resin and the phosphate-loaded resins were identified by analyzing the thermogravimetric data through the Kissinger method. Since the ammonium polyphosphate-containing resin showed greater thermal and fire performance than the other systems, it was used to manufacture unidirectional glass fiber composites by a vacuum infusion process. The oxidative pyrolysis and fire behavior of the composites produced were studied using thermogravimetric and cone calorimeter tests that demonstrated improvement of their thermal stability and fire performance.

Layup Analyzing of a Carbon/Glass Hybrid Composite Wind Turbine Blade Using Finite Element Analysis

This thesis use AOC15/50 blade as baseline model which is a composite wind turbine blade made of glass/epoxy for a horizontal axis wind turbine. A finite element modeling of composite wind turbine blade was created using the SHELL element of ANSYS. Then we study how to use the carbon fiber material replaces the glass fiber to make the hybrid blade, and find a suitable layup to improve the performance of the blade. The hybrid blade was made through introducing carbon fibers. Different models, with introducing different number of carbon fibers, 75% carbon fibers replace unidirectional glass fibers in spar cap of blade model which can achieve best structure performance. The wind turbine blades are often fabricated by hand using multiple of glass fiber-reinforced polyester resin or glass fiber-reinforced epoxy resin. As commercial machines get bigger, this could not to meet the demands. The advantages of carbon fiber composite materials are used by blade producer. Studies show that carbon fiber has high strength-to-weight ratio and resistance fatigue properties. Carbon fiber is mixed with epoxy resin to make into carbon fiber-reinforced polymer. Carbon fiber-reinforced polymer is the one of best blade materials for resistance bad weather. The stiffness of carbon fiber composite is 2 or 3 times higher than glass fiber composite [1], but the cost of carbon fiber composite is 10 times higher than glass fiber composite. If all of wind turbine blades are made of carbon fiber composite, it will be very expensive. Therefore carbon/glass fiber hybrid composite blade has become a research emphasis in the field of blade materials. This paper gives an example of finite element modeling composite wind turbine blade in ANSYS by means of the medium-length blade of AOC 15/50 horizontal axis wind turbine. This model can be directly used in dynamics analysis and does not need to be imported from the CAD software into finite element program. This finite element modeling of composite wind turbine blade was created using the SHELL element of ANSYS. Then we study how to use the carbon fiber material replaces the glass fiber to make the hybrid blade, and find a suitable lay-up to improve the performance of the blade.

Solid Particle Erosion of Particulate Filled Short Glass Fiber Reinforced Polyester Resin Composites

Fiber reinforced composite materials have been used in main parts of structures; an accurate evaluation of their erosion behavior becomes very important. In this study, short glass fibre reinforced polyester based isotropic polymer composites are fabricated with five different fibre weight-fractions. The effect of various operational variables, material parameters and their interactive influences on erosive wear behavior of these composites has been studied systematically. After systematic analysis of solid particle erosion for all the five composites, 30wt% short glass fiber reinforced polyester based composite shows better erosion resistance. In order to improve the erosion resistance further ceramic silicon carbide particle is reinforced with the 30wt% glass-polyester based hybrid composites. A finite element (FE) model (LS-DYNA) of erosive wear is established for damage assessment and validated by a well designed set of experiments. For this, the design of experiments approach using Taguchi’s orthogonal arrays design is used. It is recognized that there is a good agreement between the computational and experimental results, and that the proposed simulation method is very useful for the evaluation of damage mechanisms.

Uniaxial ratchetting of polymer and polymer matrix composites: Time-dependent experimental observations

The uniaxial time-dependent ratchetting of polyester resin and glass fiber reinforced polyester resin matrix composites was observed by the stress-controlled cyclic tension–compression with non-zero tensile mean stress and tension–tension tests at room temperature. After the ratchetting of the polyester resin had been observed by the cyclic tests with different loading conditions including some time-related factors, such as stress rate and peak stress hold, the ratchetting evolutions of the continuous and short glass fiber reinforced resin matrix composites were also investigated by the stress-controlled cyclic tests, respectively. It is concluded that: both the polyester resin and its composites present apparent ratchetting deformation, i.e., the ratchetting strain accumulates progressively in the tensile direction during the cyclic tension–compression with non-zero tensile mean stress and tension–tension tests; the ratchetting depends on the applied stress amplitude, mean stress, stress rate and peak stress hold, and the time-dependent ratchetting is obvious even for the continuous glass fiber reinforced resin matrix composites with high fiber volume fraction (such as 40% and 50%); the time-dependent ratchetting of the polyester resin and its composites mainly stems from the viscosity of the polyester resin, while the addition of glass fiber into the resin matrix improves the resistance of the composites to the ratchetting deformation and lowers the time-dependence of the ratchetting simultaneously.

Combined impact and fatigue of glass fiber reinforced composites

The low velocity impact and tension–tension fatigue behavior of glass fiber reinforced polyester resin composites have been investigated. Two fiber geometries, namely [±45°] 4 and [0/90°] 2s stitch bonded glass fibers were studied. The results revealed that even low energy impact could seriously impair the tensile properties of [±45°] 4 composites. For the [0/90°] 2s glass fiber composites, a critical impact energy was found. Below this energy level the tensile properties were hardly affected by the impact but above it the tensile properties reduced with increasing energy. Low velocity impact also reduced the fatigue lives of the composites and this reduction could be related to the degradation in tensile strength. By normalizing the fatigue stress against the post-impact residual tensile strength of the composite, it was found that for each fiber geometry a single S–N curve could be drawn, which encompassed both undamaged and impacted samples. This implies that fatigue lifetimes of impact damaged composites can be predicted from measurement of the residual tensile strength of impacted specimens and the S–N curve of undamaged samples.

Exterior components based on renewable resources produced with SMC technology—Considering a bus component as example

The importance of renewable resources in technical applications has increased. Within the framework of the studies, a bus body component based on natural fibres and PTP ®, a vegetable based thermoset resin, is produced with the sheet-moulding-compound technology (SMC). Hitherto, the conventional component was produced of glass fibre reinforced polyester resin. The mid-term results of the studies show that it is possible to optimise the production of this textile semi-finished part by selecting qualified hemp fibres and developing a technically matured PTP ®-SMC variant in such a way that the component production process based on the semi-finished parts need not be changed. All in all, it was possible to produce a homogeneous body part with the hemp/PTP ®-prepreg due to the flow ability that was achieved for the natural fibres. The technical feasibility of producing an SMC-component based on renewable resources was demonstrated. The properties of the component, e.g. tensile strength, burning behaviour and water absorption, are shown and compared to the results of the series component. An assessment of the component from the end-user perspective is presented. According to the End-of-Life Vehicles Regulation, there is no advantage in components based on renewable resources over components based on petrochemical resources. However, the application of renewable resources has advantages in terms of recycling technologies, which are accepted for SMC and which will become economically more important in the future. In comparison with the polyester system, the life-cycle assessment of the polymer material PTP ® shows lower values in nearly all impact categories.

Interfacial phenomena in glass fibre reinforced polyester resin with low profile additives Part I Micromechanical evaluation by pull out testing

The interfacial response of a glass fibre/unsaturated polyester resin matrix composite has been evaluated by means of single fiber pull-out tests. The nature of fibre sizing, more specifically sizing solubility, affects the debonding behavior. A confrontation of experimental data to current micromechanical models, assuming either mechanical or energetic criteria, proves quite efficient in relating stability of the debonding process to sizing characteristics.

Moisture effects on the toughness, mode-I and mode-II of particles filled quasi-isotropic glass–fibre reinforced polyester resin composites

An experimental programme is presented for the effect of moisture on the toughness, mode-I and mode-II of aluminium tri-hydrate and polyethylene filled and unfilled quasi-isotropic glass–fibre reinforced epoxy–vinylester resin (GFRP) composites. Specimens were exposed in water at room temperature (20°C) for a period of 8 months and the effect of moisture content on toughness, GIc and GIIc values were obtained at an interval of every 2 months. Some samples were exposed in hot water at 40°C temperature to accelerate the uptake of moisture and produce saturated composites. The results indicate that equilibrium moisture content and diffusion coefficients increase with increase of weight of filler content in GFRP composites which is linked to an increase in microscopic cracking. Also mode-I, toughness of all composites increased with an increase in moisture uptake, mode-II toughness was relatively unaffected. Aluminium-tri-hydrate filled GFRP composites showed a higher moisture uptake, which resulted in higher values of both mode-I and mode-II, toughness than the polyethylene filled and unfilled GFRP composites. © 1998 Chapman & Hall

Damage performance of particles filled quasi-isotropic glass–fibre reinforced polyester resin composites

The purpose of this work was to determine the toughening mechanisms in interlayered quasi-isotropic glass–fibre reinforced polyester resin (GFRP) composites. Particles of polyethylene and aluminium tri-hydrate, Al(OH)3, were mixed with the polyester resin prior to laminating with woven E-glass-fibre cloth. Mode-I, mode-II, and impact tests were performed to determine critical strain energy-release rates (GIc and GIIc), absorbed energy and residual compressive strength for the laminates with and without particulate additions. Mode-I and mode-II delamination toughness were characterized using double cantilever beam (DCB) and end-notched flexure (ENF) specimens, respectively, and the delaminated surfaces of specimens were examined using scanning electron microscopy (SEM) to investigate the interlaminar morphology after fracture. The results indicate that the interlaminar toughness (GIc and GIIc), absorbed energy and residual compressive strength values of the GFRP composite increases with increase of particle content. The improved behaviour of particle containing GFRP is linked to stress-concentration induced plastic deformation and crack bridging. Polyethylene particles increase the toughness of the matrix material, which results in composites with higher values of mode-I, mode-II and impact than the composites with aluminium tri-hydrate particles. © 1998 Chapman & Hall

Durability of Closed-End Pressurized GRP Pipes under Hygrothermal Conditions. Part I: Monotonic Tests

Environmental factors are of extreme importance with respect to the ser-vice life of composite components based on polymeric engineering matrices. Part I deals with the role of matrix ductility and chemical environmental degradation on the composites mechanical properties. Part II is concerned with the lifetime prediction of GRP filament wound pipes under low pressure levels and hygrothermal conditions. There composites are an E glass fiber reinforced polyester resin and an ECR glass fiber reinforced vinylester resin. The mechanical behavior of the pipes before and after exposure to water for different duration is studied through internal pressurizing tests with closed end procedure. The results indicate that in the hoop direction, fibers carry the complete load while in the axial direction there is a substantial contribution from the matrix. The use of elasticity theory appears as an appropriate method to describe the mechanical behavior of the pressurized pipes under monotonic loading conditions. In the hoop direction the behavior is governed by the fibers one whereas in the axial direction damage must be accounted for in the elastic law. Chain scission effects on the mechanical properties are investigated. Experimental results show that the mechanical properties, the damage mechanisms and the failure mode of the pipes are changed by water uptake. Relations between the mechanical properties and the exposure duration based on physical considerations are assessed, allowing for the definition of a damage parameter related to hygrothermal degradation. Environmental effects (swelling and chain scission) mainly affect the yielding pressure and the pressure to failure, whereas load condition and initial defects affect the axial modulus. This leads to the definition of two independent damage parameters.