Woven Glass Fiber Research Articles

Numerical evaluation of the retrofit effectiveness for polyurea-woven glass fiber mesh composite retrofitted RC slab subjected to blast loading

Polyurea (PU), which has a high elongation and energy absorption, is widely used as a retrofitting coating for building structure. However, the load-carrying capacity and flexural stiffness of the PU retrofitted structure cannot be fully enhanced under blast load as the low stiffness of the PU coating. To overcome this drawback, the woven glass fiber mesh (WGF) was selected as a 'soft rebar' to combine with PU to form a PU-WGF composite coating. Firstly, three reliable finite element (FE) models based on field explosion test setup were developed using LS-DYNA and verified according to the test data. Then, parametric analyses, comparison analysis and damage assessment were conducted by numerical simulation methods, where the developed models were verified by the field explosion tests. Results show that WGFs can increase the energy absorption of PU coating to 2.5 times, and downgrade the damage degree of its retrofitted RC slab, especially a collapse and severe damage occurs in it. On the contrary, the PU coating can hardly achieve this goal, which is mainly used to prevent the spalling of the explosion concrete fragments.

Effect of boundary condition and variable shell thickness on the vibration behavior of grid-stiffened composite conical shells

In this research, it is aimed to investigate the effect of boundary condition and variable shell thickness on the vibration behavior of grid-stiffened composite conical shells. In order to fabricate the stiffeners and shell for the experimental study, continuous and woven glass fibers have been used during a filament winding process, respectively. Due to the non-uniform distribution of the stiffeners in a stiffened conical shell, the equivalent thickness varies along the longitudinal axis. The stiffener and shell structures have been reduced into an equivalent shell using smeared method. The governing equations have been solved in order to evaluate the natural frequencies of the grid-stiffened conical shell by the use of first-shear deformation theory (FSDT) along with the power series method. In order to validate the analytical solutions, an experimental modal analysis have been carried out on a real grid-stiffened composite conical shell with uniform shell thickness. In addition, the finite element solution has been provided for further validations. Furthermore, the effects of various geometric parameters, variable shell thickness and boundary conditions have been discussed.

Cyclic Relaxation, Impact Properties and Fracture Toughness of Carbon and Glass Fiber Reinforced Composite Laminates.

In this paper, the mechanical properties of fiber-reinforced epoxy laminates are experimentally tested. The relaxation behavior of carbon and glass fiber composite laminates is investigated at room temperature. In addition, the impact strength under drop-weight loading is measured. The hand lay-up technique is used to fabricate composite laminates with woven 8-ply carbon and glass fiber reinforced epoxy. Tensile tests, cyclic relaxation tests and drop weight impacts are carried out on the carbon and glass fiber-reinforced epoxy laminates. The surface release energy GIC and the related fracture toughness KIC are important characteristic properties and are therefore measured experimentally using a standard test on centre-cracked specimens. The results show that carbon fiber-reinforced epoxy laminates with high tensile strength give high cyclic relaxation performance, better than the specimens with glass fiber composite laminates. This is due to the higher strength and stiffness of carbon fiber-reinforced epoxy with 600 MPa compared to glass fiber-reinforced epoxy with 200 MPa. While glass fibers show better impact behavior than carbon fibers at impact energies between 1.9 and 2.7 J, this is due to the large amount of epoxy resin in the case of glass fiber composite laminates, while the impact behavior is different at impact energies between 2.7 and 3.4 J. The fracture toughness KIC is measured to be 192 and 31 MPa √m and the surface energy GIC is measured to be 540.6 and 31.1 kJ/m2 for carbon and glass fiber-reinforced epoxy laminates, respectively.

Experimental and theoretical behavior of cementitious plates containing ethylene vinyl acetate reinforced with glass woven fabric under impact load

Abstract The paper is an analysis of the experimental and theoretical behavior of cementitious plate containing waste ethylene vinyl acetate (EVA) with and without reinforcement with glass fiber woven fabric (GFRP) under low-velocity impact load effect. Cementitious plates of 150 mm × 150 mm size and three different thicknesses (15 mm, 30 mm, 50 mm) are produced by replacing the cement mixture aggregate with EVA at 0%, 18%, 32%, 45%, and 56% by volume of aggregate. Then, the cementitious plates are coated with GFRP using vacuum infusion method. The effect of EVA and GRFP coatings on the dynamic impact behavior of cementitious plates is investigated by applying a low-velocity impact test on the produced cementitious plates with an impactor of 18 mm diameter, 10.50 kg weight, and 500 mm height. The data obtained from the experimental results are analyzed based on the mass-plate theory, lightweight (LWC) and normal weight (NWC) concrete, and the consistency of the theoretical results with the experimental results is compared. It has been determined that the use of NWC is more suitable for cementitious plates with an EVA replacement rate in the range of 0–32%, while the use of LWC offers more optimum results if the EVA ratio is in the range of 32–56%. Especially when the EVA displacement exceeds 32%, it causes excessive void formation in the structure, resulting in a reduction in the dynamic impact loads of cementitious plates. GFRP coating with vacuum infusion method is not recommended for cementitious plate structures when the EVA replacement rate exceeds 32% by volume of aggregate.

Synthesis and Characterization of Hybrid Fiber-Reinforced Polymer by Adding Ceramic Nanoparticles for Aeronautical Structural Applications.

The multiscale hybridization of ceramic nanoparticles incorporated into polymer matrices reinforced with hybrid fibers offers a new opportunity to develop high-performance, multifunctional composites, especially for applications in aeronautical structures. In this study, two different kinds of hybrid fibers were selected, woven carbon and glass fiber, while two different ceramic nanoparticles, alumina (Al2O3) and graphene nanoplatelets (GNPs), were chosen to incorporate into a polymer matrix (epoxy resin). To obtain good dispersion of additive nanoparticles within the resin matrix, the ultrasonication technique was implemented. The microstructure, XRD patterns, hardness, and tensile properties of the fabricated composites were investigated here. Microstructural characterization demonstrated a good dispersion of ceramic nanoparticles of Al2O3 and GNPs in the fabricated composites. The addition of GNPs/Al2O3 nanoparticles as additive reinforcements to the fiber-reinforced polymers (FRPs) induced a significant increase in the hardness and tensile strength. Generally, the FRPs with 3 wt.% nano-Al2O3 enhanced composites exhibit higher tensile strength as compared with all other sets of composites. Particularly, the tensile strength was improved from 133 MPa in the unreinforced specimen to 230 MPa in the reinforced specimen with 3 wt.% Al2O3. This can be attributed to the better distribution of nanoparticles in the resin polymer, which, in turn, induces proper stress transfer from the matrix to the fiber phase. The hybrid mode mechanism depends on the interaction among the mechanical properties of fiber, the physical and chemical evolution of resin, the bonding properties of the fiber/resin interface, and the service environment. Therefore, the hybrid mode of woven carbon and glass fibers at a volume fraction of 64% with additive nanoparticles of GNPs/Al2O3 within the resin was appropriate to produce aeronautical structures with extraordinary properties.

Investigation of anisotropy effects in glass fibre reinforced polymer composites on tensile and shear properties using full field strain measurement and finite element multi-scale techniques

Designing highly stressed offshore renewable energy composite structures (e.g. wind and tidal turbine blades) necessitates characterisation of woven fabric composite under off axial loading. In this work a combined method of finite element analysis, digital image correlation and microscopy is used to assess the effect of ply orientation on the tensile/shear properties and failure modes of woven glass fibre reinforced polymer composites. Full field strain maps obtained by the digital image correlation method were used to evaluate the damage development and the inhomogeneity of strain localisation. The development of finite element models of mechanical test specimens is based on the analysis of micro-mechanical models of representative volume elements using a homogenisation technique in order to calculate the effective orthotropic properties. The agreement between numerically and experimentally calculated strains obtained in the elastic regimes indicates that stress analysis conducted by numerical methods is useful when characterising the effect of ply orientation on mechanical behaviour. Strain measurement conducted by the digital image correlation method indicated that there is a strong relationship between the strain distribution and the microstructure/ply orientation. In addition, it was found that the levels of localised tensile strain are higher than the global strain indicating the structural heterogeneity of the composite material. Finally, microstructural analysis of tension and shear test specimens showed that the main failure modes are de-bonded fibres, fibre pull out, in-plane/inter-laminar shear cracks and delamination.

Optimization of geometric parameters for mode-I fracture analyse on glass fiber woven mat thermoplastic laminated composites

The present work is to optimize the geometric parameters such as width (W), breath, total width (C), height (h), and crack length (a) of glass fiber woven mat reinforced thermoplastic laminate composite for Mode-I fracture analysis with compact tension testing mode. The laminated HDPE composites were prepared by hot compression molding with three layers of HDPE and two-layer of glass fiber woven mat. The design of experiments (L27 Orthogonal array) was prepared based on the Taguchi technique with four parameters and three levels. The mode-I fracture toughness and energy-releasing rate were calculated for all samples. The ANOVA and regression equation were used to find the effect of toughness and energy releasing rate of the laminate composites. The experimental and regression results are compared and predicted the error. Finally, the optimum shape to laminate composites is suggested for predicting fracture behaviors of various synthetic and natural fiber woven mat reinforced polymer composites in mode-I under compact tension mode.

Improvement of technological properties of wood plastic composites reinforced with glass and carbon fibre fabric

In this study, HDPE-based flat-pressed WPCs were reinforced with glass fibre and carbon fibre woven fabrics, which could be used where high strength and stiffness are required. The effect of reinforcement on some physical, mechanical, and thermal properties and fire performance was investigated. According to the results, the increase in woven fabric density resulted in holding much water in the microvoids in the fabric, which increased water absorption up to 32.96%. Reinforcement also resulted in increased hardness. In general, continuous filaments in the fabric significantly increased mechanical properties. The improvement exceeded over 400% for tensile strength compared to unreinforced control samples, while the increases were 129% and 115% for the flexural strength and MOE, respectively. The interlocking of matrix and woven fabrics is an important factor that affects load transfer. The strong interaction between wood-polymer and the wood-polymer-woven fabric was observed from the SEM investigation. The thermal stability of composites was also improved, possibly due to the homogeneous distribution of heat within fibres. Glass and carbon fibres presumably acted as a buffer against increasing heat, increasing the onset temperature. Moreover, according to the LOI test, the need for oxygen increased from 24.72 to 26.01 with the effect of wood flour and reinforcement.

Perilaku water absorption pada komposit hybrid serat agel tenun dan serat gelas

This study aimed to investigate the effect of alkali treatment and stacking sequences on water absorption and flexural strength in woven agel and glass fibers reinforced hybrid composites. The research materials are woven agel fiber, E-200 glass fiber, unsaturated polyester resin Yukalac 157 BQTN, and catalyst of methyl ethyl ketone peroxide (MEKP). The alkali treatment is carried out on the woven agel fibers by soaking the fiber in 5% NaOH solution for 1 hour. Then the fiber is washed with fresh water and dried for 48 hours. Manufacturing techniques used vacuum bagging with suction pressure of 70 cmHg at room temperature. The amount of reinforcing fiber 7 fibers consists of 3 glass fibers and 4 agel woven fibers. The water absorption test uses a 3.5% NaCl solution for 1080 hours at room temperature. Water absorption test specimens based on ASTM D570 standard. The research results showed that alkali treatment with glass fiber arrangement on the specimen surface effectively decreased water absorption and increased the flexural strength of woven agel and glass fibers hybrid composites. This can be seen from the decrease in water content in equilibrium by 8.67%, the diffusion coefficient of 5.74 x 10-12 m2/s, and the flexural strength before and after immersion, which are 135 MPa and 125 MPa respectively.

Low-Velocity Impact Analysis of Pineapple Leaf Fiber (PALF) Hybrid Composites.

The low-velocity impact behaviour of pineapple leaf fiber, PALF reinforce epoxy composite (P), PALF hybrid (GPG), and four-layer woven glass fiber (GGGG) composite was investigated. As for post-impact analysis, the damage evaluation was assessed through photographic images and X-ray computed tomography, using CT scan techniques. The key findings from this study are that a positive hybrid effect of PALF as a reinforcement was seen where the GPG shows the delayed time taken for damage initiation and propagation through the whole sample compared to GGGG. This clearly shows that the addition of fibers does have comparable composite properties with a fully synthetic composite. Through the visual inspection captured by photographic image, the presence of woven fiber glass mat in GPG presents a different damage mode compared to P. Moreover, CT scan results show extended internal damage at the cross-section of all impacted composite.

A numerical investigation of the effect of fiber orientation on the natural frequency of hybrid composite laminate.

In this study, the effect of fiber orientations on the natural frequencies of the hybrid composite laminate (HCGFRE) that is consisted of sequential stacking of plain woven carbon fiber reinforced epoxy (CFRE) and plain woven glass fiber reinforced epoxy (GFRE) fibers was investigated. A finite element approach was carried out in order to determine the natural frequencies of hybrid composite laminate. Analyzes were performed using the LS-DYNA® software. In the finite element analysis, the natural frequencies corresponding to the first three modes were determined separately for each fiber orientation (00,300,450). Besides the modal analysis of hybrid composite laminates formed by sequential stacking of the same fiber orientations, the natural frequencies of hybrid composite laminates formed by stacking in different fiber orientations were also examined within the scope of the study. The same boundary conditions were applied for all fiber orientations since it is essential to study with a similar degree of freedom. In addition, the effect of the mesh sensitivity used in the finite element approach on the natural frequency is also considered. it is seen that both the change of fiber orientation and the stacking of composite plates with different fiber orientations directly affect the natural frequency values for all modes.

Mechanical and Abrasive Wear Performance of Titanium Di-Oxide Filled Woven Glass Fibre Reinforced Polymer Composites by Using Taguchi and EDAS Approach.

Two-body abrasive wear behavior of glass fabric reinforced (GC) epoxy and titanium dioxide (TiO2) filled composites have been conducted out by using a tribo test machine. GC and TiO2 filled GC composites were produced by the hand layup technique. The mechanical performances of the fabricated composites were calculated as per ASTM standards. Three different weight percentages were mixed with the polymer to develop the mechanical and abrasive wear features of the composites. Evaluation Based on Distance from Average Solution (EDAS), a multi-criteria decision technique is applied to find the best filler content. Based on the output, 2wt% TiO2 filler gave the best result. Abrasive wear tests were used to compare GC and TiO2 filled GC composites. The abrasion wear mechanisms of the unfilled and TiO2 filled composites have also been studied by scanning electron microscopy. The outcome of the paper suggests the correct proportion of filler required for the resin in order to improve the wear resistance of the filled composites. Taguchi combined with Multi-Criteria Decision Method (MCDM) is used to identify the better performance of the TiO2 filled epoxy composites.

Investigations of low-velocity impact behaviour of single-lap joints having dissimilar hybrid composite adherends through cohesive zone model approach

The low-velocity impact behavior of single-lap joints was investigated in this study. In single-lap joints, woven carbon fiber reinforced epoxy (CFRE) and plain woven glass fiber reinforced epoxy (GFRE) laminates as well as a hybrid composite laminate (HCGFRE), which is formed by stacking carbon and glass composite laminates, are used as adherends. Araldite 2011 and Araldite 138 M/HV998 epoxy adhesives were used with different mechanical properties for joining similar and dissimilar composite adherends. Low-velocity impact tests were carried out with 40 J impact energy. Reaction force-time and impact energy-time graphs were obtained from the experimental study as impact response. In numerical analyses, the damage approach of composite adherend was modeled using composite stress-based failure model (Mat 59) and adhesives were modeled utilizing a mixed-mode cohesive zone model (Mat 138) that existed in LS-DYNA explicit finite element software. It was seen that the numerical results indicated a similar tendency with the experimental results due to the modeling of the adhesives using the proper cohesive zone model, the application of correct boundary conditions, and the selection of the correct contact type.

Free Vibration Behavior of Angle-Ply Laminated Composite Stiffened Plates

This paper reports for the first time the experimental investigation on the free vibration characteristics of angle-ply laminated composite stiffened plates along with the numerical investigation. The natural frequencies of these plates are computed experimentally using an FFT analyzer and numerically by employing the finite element method with combination of isoparametric nine nodded plate and three nodded beam elements. Angle-ply laminated stiffened plates are fabricated using woven glass fiber fabrics and epoxy by hand layup technique. The effects of various support conditions; number, orientation and types of stiffeners; aspect ratios of plates and different fiber orientations on the fundamental frequencies of the angle-ply laminated stiffened plates are investigated. These parameters significantly influence the natural frequencies. It is found that there is a very good agreement observed between the fundamental frequencies obtained from both experimental and numerical investigation. Mode shapes are also presented for angle-ply laminated square stiffened plates with three different support conditions to justify the trend of increasing/decreasing of the modal frequency with the addition of stiffeners. It is observed that the enhancement of the frequencies of the angle-ply plates due to addition of stiffeners is influenced significantly by the position of stiffeners and consequently mode shapes. As the research on the free vibration behavior of angle-ply stiffened plates with experimental analysis is very rare, this study can be considered as the benchmark for future research.

Properties and Structure of UV Light Cured CIPP Composites

One of the methods of curing (Cured-In-Place Pipe) CIPP pipes is the curing using ultraviolet (UV) light. The main difference from common CIPP types is in the structure of the liner material. In terms of material, it is a woven fiber glass fabric which is saturated with vinyl ester or polyester resin. In general, these pipes are more resistant to chemicals and achieve higher values of flexural properties. The paper focuses on the investigation of the short-term mechanical properties using three-point bending test and structure of UV cured CIPP liners. The computed tomography (CT) was used for the analysis of CIPP internal structure and composition.

Optimization of a Totally Fiber-Reinforced Plastic Composite Sandwich Construction of Helicopter Floor for Weight Saving, Fuel Saving and Higher Safety

The application of fiber-reinforced plastic (FRP) composites as structural elements of air vehicles provides weight saving, which results in a reduction in fuel consumption, fuel cost, and air pollution, and a higher speed. The goal of this research was to elaborate a new optimization method for a totally FRP composite construction for helicopter floors. During the optimization, 46 different layer combinations of 4 different FRP layers (woven glass fibers with phenolic resin; woven glass fibers with epoxy resin; woven carbon fibers with epoxy resin; hybrid composite) and FRP honeycomb core structural elements were investigated. The face sheets were composed of a different number of layers with cross-ply, angle-ply, and multidirectional fiber orientations. During the optimization, nine design constraints were considered: deflection; face sheet stress (bending load, end loading); stiffness; buckling; core shear stress; skin wrinkling; intracell buckling; and shear crimping. The single-objective weight optimization was solved by applying the Interior Point Algorithm of the Matlab software, the Generalized Reduced Gradient (GRG) Nonlinear Algorithm of the Excel Solver software, and the Laminator software. The Digimat-HC software solved the numerical models for the optimum sandwich plates of helicopter floors. The main contribution is developing a new method for optimizing a totally FRP composite sandwich structure—due to its material constituents and construction—that is more advantageous than traditional helicopter floors. A case study validated this fact.

Research on drilling CFRP laminate with a thin woven glass fiber surface layer using plane rake–faced twist drill

The delamination produced during drilling CFRP will affect its structural strength seriously. Delamination is closely related to the thrust force during drilling, which is closely related to the tool, so it is particularly important to choose the tools with appropriate geometric structure. Many scholars used tools with different geometric structure to drill CFRP, and then conducted the drilling damage analyses and drilling mechanism researches. It finally came to a conclusion that a drill with a special structure had certain advantages compared with a common twist drill in the drilling process. A new type of plane rake–faced twist drill was used to drill the CFRP laminate with a thin-woven glass fiber surface layer. Experimental results showed that the plane rake–faced twist drill along cutting edge had a constant reference rake angle value, which caused the plane rake–faced twist drill generated smaller thrust force and less drilling damage than the common twist drill. As the reference rake angle of the plane rake–faced twist drill increased, the thrust force and drilling damage decreased. It was revealed the inhibition of the thin-woven glass fiber surface layer on the drilling damage at entrance and exit. Finally, it was proposed that when the plane rake–faced twist drill was used to drill CFRP laminate with a thin-woven glass fiber surface, 46° reference rake angle should be selected.

Mechanical response of full-scale geosynthetic-reinforced asphalt overlays subjected to repeated loads

This study aims at evaluating the influence of geosynthetic reinforcements on the structural improvement of asphalt overlays placed on distressed pavement layers using repeated load tests. Full-scale instrumented pavement models were constructed in an indoor steel tank measuring 1000 mm in length, 1000 mm in width and 1000 mm in depth. Full-scale instrumented pavement models consisted of a 650-mm-thick weak subgrade, 250-mm-thick base, 90-mm-thick distressed asphalt layer, binder tack coat, geosynthetic reinforcement (except in control sections), and 50-mm-thick hot mix asphalt overlay. Sensors used in the instrumentation program included earth pressure cells and linear variable displacement transformers installed on the subgrade and surface layers, respectively. Four different geosynthetic types, including woven geo-jute mat (GJ), polypropylene geogrid (PP), polyester geogrid (PET), and fiberglass geogrid composite (FGC) were adopted as asphalt reinforcements. A servo-hydraulic actuator was used to replicate a live traffic wheel load by applying an equivalent single axle contact pressure of 550 kPa at a frequency of 1 Hz. Repeated load tests were terminated after 100,000 load cycles and the behaviour of geosynthetic-reinforced full-scale models was compared with that of unreinforced model. Performance indicators, including Traffic Benefit Ratio (TBR) and Rut Depth Reductions (RDR), were estimated and repeated load test results indicated an increase in the structural performance of geosynthetic-reinforced full-scale models in relation to that of unreinforced model. Among the geosynthetic-reinforced models considered in this study, the FGC-reinforced model showed a comparatively better performance with a maximum TBR of 20 at a permanent deflection of 5 mm and the highest RDR of 56% after 100,000 load cycles, respectively. Maximum reductions of 56% in surface deflection and of 30% in vertical pressure on the subgrade were also observed after 100,000 load cycles in the FGC-reinforced model.

Kuznets curve with parabola-shaped ultra-wideband antenna with defected ground plane for communications

PurposeThis paper aims to state the configuration of the proposed antenna which is competent to many networks such as LTE and X band applications. The experimental study encountered the significance of the proposed antenna.Design/methodology/approachA novel compact Kuznets curve with parabola-shaped quad-band notched antenna is demonstrated in this paper. The presented prototype is ascertained on a composite material composed of woven fiberglass cloth with an epoxy resin binder. The resulting ultra-wideband antenna ranges 3.1–3.54 GHz, 5.17–5.51 GHz, 5.74–6.43 GHz and 6.79–7.60 GHz. To avoid the frequency bands which cause UWB interference,the projected antenna has been incorporated with slotted patch. The proposed antenna design is attained in four steps. The simple circular patch antenna model with defected ground plane is subjected to stepwise progression by including parabola-shaped slot and U shaped slot on the patch to attain four notched bands.FindingsThis projected antenna possesses an optimal bond among simulated and measured outcomes,which is more suitable for the quad notched band applications. Substrate analysis is done by varying substrate material, and notch behavior is presented. The proposed method’s optimum performance in metrics such as return loss, voltage standing wave ratio and radiation pattern varies its frequency range from 2.56 to 7.6 GHz.Originality/valueThe antenna adaptation of the defected ground plane has achieved through the quad notched band with operating frequency ranges 2.56 to 7.6 GHz and with eliminated frequency ranges 3.55–5.16 GHz, 5.52–5.73 GHz, 6.44–6.78 GHz and 7.66–10.6 GHz.

Low velocity and compression after impact behaviors of fiber‐reinforced MA‐g‐PP and MA‐g‐ABS matrix composites

AbstractThis study mainly focused on how one layer of fiber fabric can increase the energy absorption and post‐damage behaviors of composite structures. For this purpose, the low velocity and compression after impact behaviors of thermoplastic matrix composite materials were experimentally investigated. A total of 0.1%–0.3% maleic anhydride grafted polypropylene and 0.3%–0.5% maleic anhydride grafted acrylonitrile butadiene styrene polymers were used as the matrix materials, whereas only single‐layer plain weave aramid fiber, carbon fiber, and glass fiber fabric were used as the reinforcement materials. The impact tests were conducted at the energy values of 20, 50, and 80 J. The results showed that the aramid fiber increased energy absorption on every level of impact energy for both matrix materials, while the carbon and glass fiber fabrics only increased the energy absorption of the MA‐g‐ABS matrix. They negatively affected the energy absorption of the MA‐g‐PP polymer. No reinforcement materials had any contribution to the maximum CAI strength value of the two matrix materials, especially in the MA‐g‐ABS composites, while all reinforcement materials increased the maximum strain values of MA‐g‐ABS up to 75%. They did not increase the CAI strain values of MA‐g‐PP due to the flexible structure of polypropylene.