Glass Fiber Reinforced Plastic Composites Research Articles

Raman spectroscopic study and statistical modeling of composition-structure-property of MgO-CaO-Al2O3-SiO2 based glasses

Lightweight, glass fiber reinforced plastic composites (GFRP) have gained a broad, global acceptance in commercial markets, among which wind turbine blade for the renewable energy sector is one of the fastest growing areas. The usfsupplee of longer wind turbine blades can effectively reduce the cost of energy generation. However, it requires a fiberglass product with a higher tensile modulus to make the blades stiffer to meet the blade deflection requirement under severe weather conditions. Traditional wind turbine blades are made from conventional E-Glass fibers with and without boron. E-Glass is primarily composed of CaO-Al2O3-SiO2 (CAS) with and without minor components of MgO (less than 4 %) and/or B2O3 (less than 1 %). Glass with higher modulus belongs to MgO (>7 %) -CaO-Al2O3-SiO2 (MCAS) system or R-Glass. Our study focuses on the effects of selective key oxides on the glass network structure by using Raman spectroscopic technique. The Raman derived plausible structure groups are then used to build statistical structure (S) – property (P) models. The S-P models are then compared with the conventional statistical C-P models. A good agreement between S-P and C-P models led to the final construction of C-S-P model platform for future glass design.

Optimization of Machining Parameters for Enhanced Performance of Glass-Fibre-Reinforced Plastic (GFRP) Composites Using Design of Experiments

A high strength-to-weight ratio, stiffness, fatigue resistance, a low coefficient of thermal expansion, and tailorable properties make glass-fibre-reinforced plastic (GFRP) a popular choice for a wide range of applications, including aircraft structures, automobile chassis, and shipbuilding. However, milling GFRP composites is challenging because of their heterogeneous nature and two-phase structure, which lead to high cutting forces and delamination. A statistical experiment was carried out using the Taguchi design of experiments to investigate the effect of machining settings on GFRP composite performance metrics such as surface delamination, surface roughness, and material removal rate. The L27 orthogonal array was used for the experiment, and it served as the foundation for the choice of material, input variables, levels, and output response variables. The experiment’s outcomes were analysed using MINITAB software® 18 Version and the Analysis of Variance (ANOVA) method. Based on the signal-to-noise (S/N) ratio, the ideal conditions were selected, and confirmation studies were carried out to ensure their applicability. In order to identify the ideal circumstances for the manufacturing and machining parameters, the data were normalised to a range from zero to one. To overcome the difficulties involved in milling GFRP composites, a thorough investigation and optimisation of the manufacturing process factors and machining settings is essential.

Optimization of Hole quality parameters using TOPSIS method in drilling of GFRP composite

The attractive mechanical properties and light weight to strength ratio Glass Fiber Reinforced Plastic (GFRP) composites are preferred in automobile and aerospace industries. Drilling process is one of the basic and important manufacturing processes. Drilling of GFRP and its issues with hole quality are fiber crack, roughness of surface, dimensional error and delamination. In this work, the effect of three different drill (Slot type, twist type and brad type) and process parameters (machining speed and feed rate) on hole quality error is analyzed. Hole quality parameters, chosen are roundness error, roughness of the machined area, delamination factor and diameter deviation. Simultaneous optimization of multiple objectives is difficult task. Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) is used for optimization process parameters and minimize the hole quality error during drilling of GFRP composite. The result revealed that spur type drill with higher range of spindle speed was provided less error in the drilled holes. Also, TOPSIS procedure has minimum computational time because of its less computational steps and highly preferrable for various decision-making problems in manufacturing industry. Hole quality error is directly influencing the assembly accuracy and its minimization is important one.

The Wrinkles Characterization in GFRP Composites by Infrared Active Thermography.

An experimental study has been carried out to assess the effectiveness of infrared thermography in wrinkle detection in composite GFRP (Glass Fiber Reinforced Plastic) structures by infrared active thermography. Wrinkles in composite GFRP plates with different weave patterns (twill and satin) have been manufactured with the use of the vacuum bagging method. The different localization of defects in laminates has been taken into account. Transmission and reflection measurement techniques of active thermography have been verified and compared. The section of a turbine blade with a vertical axis of rotation containing post-manufacturing wrinkles has been prepared to verify active thermography measurement techniques in the real structure. In the turbine blade section, the influence of a gelcoat surface on the effectiveness of thermography damage detection has also been taken into account. Straightforward thermal parameters applied in structural health monitoring systems allow an effective damage detection method to be built. The transmission IRT setup allows not only for damage detection and localization in composite structures but also for accurate damage identification. The reflection IRT setup is convenient for damage detection systems coupled with nondestructive testing software. In considered cases, the type of fabric weave has negligible influence on the quality of damage detection results.

Effect of stress ratio on the tension–tension fatigue behavior of tungsten carbide nanoparticles toughened GFRP

AbstractThe fatigue behavior of woven ply (0/90°) glass fiber reinforced plastic (GFRP) laminates filled with 2 wt.% of tungsten carbide nano‐powder at different stress ratios, 0.1 and 0.3, was investigated. Specimens were subjected to constant amplitude fatigue loading for three stress levels, 80%, 70%, and 60%, of ultimate tensile strength at each stress ratio for both neat GFRP and tungsten carbide modified GFRP (GFRP‐WC). The fatigue life was enhanced at all stress levels in neat GFRP composites with an increase in stress ratio from 0.1 to 0.3. In addition, incorporation of nanoparticles also increases fatigue life at all stress levels for both stress ratios. The addition of nanoparticles acts as a barrier to crack propagation, which leads to a significant effect on the evolution of fatigue stiffness, cyclic creep strain, and dissipated energy during cyclic loading at both stress ratios.

EXPERIMENTAL EVALUATION OF PARAMETERS AFFECTING DELAMINATION FACTOR, TENSILE STRENGTH, THRUST FORCE AND SURFACE ROUGHNESS IN DRILLING OF GFRP

The drilling of glass fiber-reinforced plastic (GFRP) composites gained importance since they are used as structural components in many industries such as automotive, aerospace, and aviation. A large number of holes are needed in the industry to join these composite parts. However, some failures occur in drilling GFRP composites, such as delamination, matrix cracking, and fiber breakage. These failures not only reduce the strength of the composite, but also reduce its service life. Drilling parameters, drill bits, and woven types have a great influence on the occurrence of these failures by greatly influencing the thrust force, surface quality, and cutting temperature. In this study, the effects of drilling parameters and woven types of GFRP composites on thrust force, surface roughness, delamination factor, and cutting temperature were examined in the drilling of uni-directional (UD), [Formula: see text] and 0[Formula: see text] GFRP woven composites. The effects of drilling parameters and the delamination factor on the tensile strength of the drilled specimen were also investigated. The result of this study indicated that thrust force, delamination factor, and surface roughness increased with increasing cutting speed and feed rate. An increase in feed rate decreased the cutting temperature, while an increase in cutting speed increased the cutting temperature. Also, it was found that the delamination factor had a critical influence on the tensile strength of the GFRP composites.

Support Vector Regression approach for prediction of delamination at entry and exit during drilling of GFRP Composites

The demand for Composites in the modern era have increased immensely due to its vast applications and superior properties over conventional materials. Glass Fibre Reinforced Plastic (GFRP) is one of the economic alternative to conventional engineering materials due to its high specific modulus of elasticity, high specific strength, good corrosion resistance, high fatigue strength and lightweight. Components made out from GFRP composites are usually near net shaped and require holes for assembly integration. Drilling is an important process as concentrated forces can cause major damage to the composite. Drilling of GFRP causes various damage such as thermal degradation, fibre breakage, matrix cracking and delamination. A substantial damage is caused by delamination which can occur both on the entry and exit sides of the composite, exit side delamination considered more severe. Therefore, selection of proper process parameters during drilling operation is very much essential. In the present work, a support vector regression (SVR) model is developed to predict the delamination at entry and exit during the drilling of GFRP composites. The model is developed based on the data obtained from experimentation. The model accuracy is evaluated by the three performance criteria including root mean square error (RMSE), Nash–Sutcliffe efficiency co-efficient (E) and co-efficient of determination (R2). The model provides an inexpensive and time saving alternative to study the delamination at entry and exit of the GFRP composite actual drilling operation.

Improvement of Fire Resistance and Mechanical Properties of Glass Fiber Reinforced Plastic (GFRP) Composite Prepared from Combination of Active Nano Filler of Modified Pumice and Commercial Active Fillers

Glass fiber reinforced plastic (GFRP) composites have great potential to replace metal components in vehicles by maintaining their mechanical properties and improving fire resistance. Ease of form, anti-corrosion, lightweight, fast production cycle, durability and high strength-to-weight ratio are the advantages of GFRP compared to conventional materials. The transition to the use of plastic materials can be performed by increasing their mechanical, thermal and fire resistance properties. This research aims to improve the fire resistance of GFRP composite and maintain its strength by a combination of pumice-based active nano filler and commercial active filler. The nano active filler of pumice particle (nAFPP) was obtained by the sol-gel method. Aluminum trihydroxide (ATH), sodium silicate (SS) and boric acid (BA) were commercial active fillers that were used in this study. The GFRP composite was prepared by a combination of woven roving (WR) and chopped strand mat (CSM) glass fibers with an unsaturated polyester matrix. The composite specimens were produced using a press mold method for controlling the thickness of specimens. Composites were tested with a burning test apparatus, flexural bending machine and Izod impact tester. Composites were also analyzed by SEM, TGA, DSC, FT-IR spectroscopy and macro photographs. The addition of nAFPP and reducing the amount of ATH increased ignition time significantly and decreased the burning rate of specimens. The higher content of nAFPP significantly increased the flexural and impact strength. TGA analysis shows that higher ATH content had a good contribution to reducing specimen weight loss. It is also strengthened by the lower exothermic of the specimen with higher ATH content. The use of SS and BA inhibited combustion by forming charcoal or protective film; however, excessive use of them produced porosity and lowered mechanical properties.

Experimental study for the effect of hole notched in fracture mechanics of GLARE and GFRP composites subjected to quasi-static loading

The requirements for the use of lightweight structures, damage-resistant materials, and optimal fuel consumption in various industries such as aerospace, marine, and automotive structures have increased the need for designing new structural systems to meet these demands. According to research, Fiber Metal Laminates (FMLs) are excellent candidates to meet the above needs. In this study, the tensile test specimens were fabricated according to ASTM D 3039 standard from plain textured glass fibers, aluminum sheet Al 6061-T6 with a thickness of 0.5 mm, and epoxy resin with lay-up of [AL/(GFRP [0,90]4)/Al/(GFRP [0,90]4)/Al]. Glass Fiber Reinforced Plastic (GFRP) specimens were also constructed using E-GLASS fibers with [0,90]20 lay-up. GLARE and GFRP specimens were subjected to tensile testing in two types of simple and open-hole at ambient temperature at the loading rate of 2 mm/min. Failure modes of the simple specimens were studied with open-hole specimens. The failure mechanism in simple glass laminate aluminum reinforced epoxy (GLARE) was delamination, however, in open-hole GLARE, no delamination occurred except for some areas around the hole, and the specimen was broken in the hole area. Open-hole GFRP‌ specimens were all broken in the hole area and simple specimens mainly in several regions in the gauge length range. Scanning Electron Microscopy (SEM) images recorded from the hole area of ​​GLARE‌ specimens clearly show that local debonding in the area around the hole caused the breakage of the specimen. In addition, the ratio of the ultimate stress of the simple GFRP‌ specimen to the open-hole specimen is 1.18 and the same ratio is 1.07 for GLARE‌ specimens. This indicates less hole effect on the ultimate stress in GLARE specimens than in GFRP. Furthermore, curved fibers around the hole can be used to reduce damage due to fracture and delay in its occurrence.

High-velocity impact behaviour of curved GFRP composites for rail vehicles: Experimental and numerical study

This study aims to explore the projectile impact behaviour of curved glass fibre reinforced plastics (GFRP) composites for rail vehicles through experimental and numerical methods. Quasi-static material tests were firstly carried out to obtain the tensile, compression, shear and bending properties. Then, high-velocity impact tests under different velocities were conducted for curved GFRP plates, which were cut from hood covers of a rail vehicle. The residual velocity of the projectile, the failure modes and the energy absorption of the composite targets were analysed. The classical Lambert-Jonas equation was used to predict the critical perforation velocity, which was also verified by the following finite element (FE) simulation in LS-DYNA. Based on the validated FE model, the effects of the impact velocity (65.14–152.22 m/s), target thickness (2 mm–8 mm) and impactor shape (flat, blunt, hemisphere and sphere) on the high-velocity impact performance of the target were studied. The results showed that the predicted critical perforation velocity of the curved GFRP plate with thickness of 6 mm was about 101.98 m/s in this study, and only local damages were observed near the trajectory. Increasing the thickness of the GFRP plate can improve its anti-penetration capability, however, the 4-mm plate possesses the highest specific energy absorption among the thickness of 2 mm–8 mm. Compared to the sharp impactors, the flat impactor resulted in the highest peak force of 260.39 kN and the maximum specific energy absorption of 502.65 J in the curved GFRP plates with thickness of 6 mm, due to the shear failure mechanism and the formation of embolism.

The Use of Acoustic Emission to Determine the Safe Load Range of GFRP Composites Used in Ship and Aviation Structures

Abstract The article presents the methodology and results of strength tests with simultaneous registration of acoustic emission. The subject of the research were glass fibre-reinforced plastics (GFRP) made by hand lamination. The obtained results allows to identify the stresses characteristic of the individual stages of the material failure process. These results can be the basis for determining the safe scope of application of the mentioned materials, especially helpful at the stage of designing ship and aircraft structures. The analysis of the test results allows to determine the safe level of stresses not exceeding about 70 MPa.

Generation of microholes on GFRP composite using ES-µ-ECDM system

Microfeatures fabrication on FRPs is very essential nowadays because of its growing demand in various industries like aerospace, automobile, space, marine, etc. Glass fiber reinforced plastic (GFRP) composite is one among the FRPs that has many potential applications with extraordinary physical, chemical and mechanical properties. Generation of microholes on GFRP composite has gained its pace in recent years because of its applications in circuit boards and filters in biomedical applications. This study focuses on the generation of microholes in GFRP composite using an in-house developed electrolyte-sonicated micro-electrochemical discharge machining (ES-µ-ECDM) system. The process parameters voltage (V), concentration (wt%), and feed rate (µm/s) are selected at three levels for performing experiments using FCC-RSM modeling. The machining responses material removal rate (MRR) and overcut (OC) are analyzed. A RSM-based regression model is developed, and a multi-objective optimization using the MOJAYA algorithm is employed to obtain a set of non-dominated Pareto optimal solutions. The Pareto optimal solution set showed a feed rate of 5 µm/s should be employed for better MRR and OC. The SEM micrographs have shown a feed rate of 5 µm/s produced smooth surfaces at voltages and concentrations less than 55 V and 17.5 wt%, respectively.

Micro-channel fabrication on GFRP composite through electrochemical spark machining method and optimization of process parameters

In the present study, fabrication of micro-channel on glass fiber reinforced plastic (GFRP) sheet has been performed through micro-electrochemical spark machining process. Box-Behnken design has been followed to conduct experiments and the influence of machining parameters and their ranges that is, applied voltage (50 V–60 V), duty factor (35%–45%), electrolyte concentration (20–30 wt%), and pulse frequency (6–10 kHz) on the micro-channel quality has been investigated. The width of micro-channel (WMC), delamination extent (DE), and heat-affected zone (HAZ) are considered as the responses. Response surface method (RSM) with desirability analysis and multi-objective optimization are utilized to optimize the process. The minimum observed WMC, DE, and HAZ are 532.81, 1.09, and 50.52 μm respectively which are obtained at machining voltage: 50 V, duty factor: 35%, concentration: 20 wt% of NaOH, and pulse frequency: 10 kHz. The fiber breakage and re-deposition/adhesion of broken fiber and matrix materials are observed at the edges of the micro-channel.

Tribological behaviour of SiC and AL2O3 filled glass-epoxy composite

Metal glass fibre reinforced composites which are considered as advanced composite materials play a significant role in aerospace, marine and automotive industries. In the current study, an attempt has been made to examine the tribological characteristics of glass fibre reinforced plastic (GFRP) composite filled with aluminium oxide (Al2O3) and silicon carbide (SiC) powder particles. Experiments were performed on pin-on-disc tribometer to evaluate the friction and wear rate as a function of normal load and sliding velocity under different conditions. For each composition of glass-epoxy composite filled with and without fillers, sliding tests were performed with normal load (20 N, 40 N, 60 N, 80 N 100 N) and sliding velocity (2.62 m/s, 4.18 m/s, 5.23 m/s, 6.85 m/s, 7.85 m/s) respectively. The metal GFRP composites were fabricated using hand-lay-up technique. The filler content (SiC & Al2O3) in epoxy-glass composite were varied. SiC was varied from 0 to 10% while Al2O3 was kept constant at 5%. To study the worn surface of glass-epoxy composite material scanning electronic microscopy is used. Before and after the experiment, weights of the composites (pin specimens) were studied on digital balance for wear loss. The present studies reported that the fabricated metal epoxy-fibre composite has performed excellent wear resistance when compared with epoxy-fibre composite without metal powders. The present work findings offer new insights into reinforcement in epoxy-glass composites with metal powders.

Optimization of hole quality parameters using TOPSIS method in drilling of GFRP composite

The attractive mechanical properties and light weight to strength ratio Glass Fiber Reinforced Plastic (GFRP) composites are preferred in automobile and aerospace industries. Drilling process is one of the basic and important manufacturing processes. Drilling of GFRP and its issues with hole quality are fiber crack, roughness of surface, dimensional error and delamination. In this work, the influence of three different types of drills (Slot type, twist type and brad type) and process parameters (feed rate and machining speed) on hole quality error is analyzed. Hole quality parameters, chosen are roundness error, roughness of the machined area, delamination factor and diameter deviation. Simultaneous optimization of multiple objectives is difficult task. Order Preference Technique by Similarity to Ideal Solution named as TOPSIS is used for optimizing the performance criteria and minimize the hole quality error during drilling of GFRP composite. The result revealed that spur type drill with higher range of spindle speed was provided less error in the drilled holes. Also, TOPSIS procedure has minimum computational time because of its less computational steps and highly preferrable for various decision-making problems in manufacturing industry. Hole quality error is directly influencing the assembly accuracy and its minimization is important one.

A Comparative Study on the Electrical and Piezoresistive Sensing Characteristics of GFRP and CFRP Composites with Hybridized Incorporation of Carbon Nanotubes, Graphenes, Carbon Nanofibers, and Graphite Nanoplatelets.

In this study, hybridized carbon nanomaterials (CNMs), such as carbon nanotubes (CNTs)–graphene, CNT–carbon nanofibers (CNFs), or CNT–graphite nanoplatelet (GNP) materials were embedded in glass-fiber-reinforced plastic (GFRP) or carbon-fiber-reinforced plastic (CFRP) composites to obtain electrical/piezoresistive sensing characteristics that surpass those of composites with only one type of CNM. In addition, to quantitatively assess their sensing characteristics, the materials were evaluated in terms of gauge factor, peak shift, and R-squared values. The electrical property results showed that the GFRP samples containing only CNTs or both CNTs and graphene exhibited higher electrical conductivity values than those of other composite samples. By evaluating piezoresistive sensing characteristics, the CNT–CNF GFRP composites showed the highest gauge factor values, followed by the CNT–graphene GFRP and CNT-only GFRP composites. These results are explained by the excluded volume theory. The peak shift and R-squared value results signified that the CNT–graphene GFRP composites exhibited the best sensing characteristics. Thus, the CNT–graphene GFRP composites would be the most feasible for use as FRP composite sensors.

THz-TDS Techniques of Thickness Measurements in Thin Shim Stock Films and Composite Materials

Terahertz wave (T-ray) scanning applications are one of the most promising tools for nondestructive evaluation. T-ray scanning applications use a T-ray technique to measure the thickness of both thin Shim stock films and GFRP (glass fiber-reinforced plastics) composites, of which the samples were selected because the T-ray method could penetrate the non-conducting samples. Notably, this method is nondestructive, making it useful for analyzing the characteristics of the materials. Thus, the T-ray thickness measurement can be found for both non-conducting Shim stock films and GFRP composites. In this work, a characterization procedure was conducted to analyze electromagnetic properties, such as the refractive index. The obtained estimates of the properties are in good agreement with the known data for poly methyl methacrylate (PMMA) for acquiring the refractive index. The T-ray technique was developed to measure the thickness of the thin Shim stock films and the GFRP composites. Our tests obtained good results on the thickness of the standard film samples, with the different thicknesses ranging from around 120 μm to 500 μm. In this study, the T-ray method was based on the reflection mode measurement, and the time-of-flight (TOF) and resonance frequencies were utilized to acquire the thickness measurements of the films and GFRP composites. The results showed that the thickness of the samples of frequency matched those obtained directly by time-of-flight (TOF) methods.

A hybrid approach for prediction of machining performances of glass fiber reinforced plastic (Epoxy) composites

In recent years, Glass Fiber Reinforced Plastic (GFRP) composites are more potential materials for usage in various structural applications in aerospace and automobile industries, owing to its favorable properties, such as light weight, specific strength, high elastic modulus and excellent corrosion resistance. This paper presents a new hybrid approach for multi-objective optimization of machining parameters on GFRP composite using Taguchi coupled grey relational (GR) and desirability function (DF) approach. The end milling of GFRP composite was performed as per Taguchi’s L16 orthogonal array by considering three input parameters: viz cutting speed (V), feed rate (F) and depth of cut (D), each at four levels. The material removal rate (MRR), surface roughness (SR) and tool wear (TW) were chosen as output responses. The main effect plot was used to determine the optimum level of machining parameters on the multiple responses. An experimental result revealed that, the optimum level of parameters obtained by GR analysis is V2F3D4. Similarly, the optimum level of parameters obtained by DF approach is V2F4D4. Moreover, analysis of variance (ANOVA) was applied to examine the significance of the parameters. Based on the ANOVA results, it has been proved that the depth of cut was the most significant parameter, trailed by feed rate and cutting speed, respectively. It was also confirmed that the P-values of depth of cut for both analyses are 0.017 and 0.039, which is less than 0.05. Finally, the confirmation tests exhibited that the DA approach was employed better in terms of determining the optimum level of machining parameters as compared to GR analysis.

Experimental Study on Fabrication and Comparison of Mechanical Properties of Plain Weave Copper Mesh Embedded Hybrid Composite with E-Glass Fiber Reinforced Epoxy GFRP Composite

This paper presents the experimental study on on GFRP (Glass-Fiber Reinforced Plastic) composite which is fiberglass reinforced with epoxy matrix and find its mechanical properties that can be compared with other hybrid composite which include plain weave copper strips mesh in between the layers of fiberglass in GFRP composite. Both type of composites are made using hand layup technique i.e., placing of chopped fiberglass sheet and then epoxy resin layer by layer, after filling of epoxy and fiberglass at 20% fiber loading which is measured by digital scale, then a pressure is also applied on this sandwich. After 24 hours it is ready to be demolded and after 48 hrs. samples was cuts as per ASTM standards then testing was done on both GFRP and Hybrid composites to find their Mechanical & Physical Properties. Results shows improvement as we introduce plain weave copper strips mesh in between the GFRP laminate to make it hybrid.

Rupture of an Industrial GFRP Composite Mitered Elbow Pipe.

This paper examines the immature rupture of glass fiber reinforced plastic composite (GFRP) mitered elbow pipes. The GFRP composite mitered elbow pipe’s lifespan was twenty-five years; however, the pipes in question experienced immature failures, resulting in the reduction of their lifetimes to seven, nine, and ten years, respectively. The GFRP cooling water mitered elbow pipe’s service conditions operate at a pressure of up to 7 bar and temperatures between 15–36 °C. The root cause of failure was determined using visual inspection, analytical, microstructural, mechanical characterizations, and chemical analysis. The initial visualization inspection revealed an improper joint between the composite overwrapped and the straight pipe sections. Mechanical properties along the axial, hoop and 45° from the axial direction were obtained. The results from the analytical analysis indicated that the elbow might withstand the operating pressure depending on the quality factor, which was confirmed to be low due to the elbow joint’s improper fabrication process. As evidence of this, the numerical analyses’ results indicated that the safety factor in withstanding the operating pressure of 5 bar is dropped down in the radial region where the thickness is reduced to simulate the failure zone. This study’s findings recommend that thickness of less than 15 mm be reinforced using overwrapped composites. It is recommended for future installations that the fabrication process be appropriately monitored and controlled and avoids using 45°/−45° fiber orientation and multiple layers of chopped strand mat glass fiber.