Glass Fiber Reinforced Plastic Composites Research Articles

Drillability study of pultruded and sheet moulding compound thick polymeric composites

This article discusses the effects of process parameters (feed and spindle speed) on quality characteristics (thrust force, torque, surface roughness and ovality) for standard and special geometric design of a drill body in dry drilling of pultruded and sheet moulding compound thick composites. Pultruded (non-laminated) and sheet moulding compound (laminated) thick glass fibre–reinforced plastic composites with a higher percentage of fibre weight fraction are extensively used in construction of bridges, prefabricated platforms, ballistic applications, structural applications, instrument bases and automotive load floors, and therefore, prediction of better performance drill helps the fabrication industry in making good quality holes. The drilling experiments using coated tungsten carbide drills, twist drill (standard geometry) and ratio drill (special geometry) of diameter of 10 mm were conducted using response surface methodology. Analysis of variance of the experimental results reveals that for both twist drill and ratio drill, feed is more significant in influencing the quality characteristics. The experimental values obtained for quality characteristics are empirically related to process parameters by developing response surface models using Design-Expert software. Analysis of the experimental results reveals that ratio drill performs better in pultruded composites and twist drill performs better in sheet moulding compound composites. The optimal process parameter levels within the selected range for minimizing all the quality characteristics together were determined.

Optimization of machining parameters in end milling of GFRP composites based on the Taguchi method with fuzzy logics

Glass Fiber Reinforced Plastics (GFRP) composite is considered to be an economic alternative to various heavy exotic materials. It is widely used in a variety of applications from aircraft to machine tools due to their light weight, high modulus, specific strength and high fracture toughness. The m achining of composite is different from the conventional machining of metal due to the composite's anisotropic and non-homogeneous nature. This paper discusses the application of the Taguchi method with fuzzy logic to optimize the machining parameters for machining of GFRP composites with multiple characteristics. A multi-response performance index (MRPI) was used for optimization. The machining parameters viz., Tool geometry (helix angle of the end mill cutter), spindle speed, feed rate, depth of cut and work piece (fiber orientation), were Optimized with consideration of multiple performance characteristics viz., machining force, delamination, surface roughness and material removal rate. The results from confirmation runs indicated that the determined optimal combination of machining parameters improved the performance of the machining process.

Effect of Drilling Parameters for the Assessment of Roughness of Drilled Holes in Glass Fiber Reinforced Plastic (GFRP)

Now a day, Glass Fibre-Reinforced Plastics (GFRP) are being widely used in diversity of engineering applications in many different areas such as aerospace, automotive and aircraft industries due to their light weight, high modulus, high specific strength and high fracture toughness. Drilling or Milling of GFRP composite material is a rather complex task owing to its heterogeneity and the number of problems, such as surface accuracy and delamination of drilled holes, which appear during the machining process, associated with the characteristics of the material and the cutting parameters. Current paper focuses the investigational details to find out roughness on drilled hole in GFRP composite laminates by using Taguchi's DOE L9 orthogonal array. The main objective of the present work is to optimize the process parameters in the drilling of GFRP composite using Taguchi DOE and to find the significance of each process parameter using ANOVA. As far as the effect of input factors are considered, the factor spindle speed is having significant and dominating effect on GFRP composite material.

Experimental Analysis and ANN Modelling of HAZ in Laser Cutting of Glass Fibre Reinforced Plastic Composites

Composite materials increasingly being used in aeronautics, aerospace, automotive and marine industries due to their high strength to weight ratio. Machining of composite material is difficult by conventional machining methods but laser cutting can offers an alternative machining method in which quality cut can be obtain by controlling different process parameters. The aim of the present research is to investigate the effect of laser cutting parameters viz. Laser Power, Cutting Speed and Gas Pressure on the response parameter HAZ. Optimization of the process parameters, their levels and combinations are decided on the basis of Taguchi L27 Orthogonal array and subsequently predictive models have been developed using Second Order Regression and Artificial Neural Network (ANN) modelling techniques. Analysis of Variance (ANOVA) is then carried out to find the relative influence of process parameters on HAZ. After comparing the simulated data with experimental data, the ANN model shows better agreement for predicting HAZ with more than 97% of accuracy for the given range of input parameters.

The Behavior of Translucent Composite Laminates under Highly Energetic Laser Irradiations

With the emergence of composite materials in the last decades, the interaction between light and diffusive materials has become a challenging topic in many key manufacturing areas (laser welding, laser surface treatment, engraving, etc.). In this paper, the behavior of laminated glass fiber-reinforced plastic composites (GFRP) under 1.07μm-wavelength irradiations is investigated. Optical parameters are first assessed to build up a basic analytical interaction model involving internal refraction and reflection. The scattering effect due to the presence of oriented glass fibers is also a topic of interest. A thermodynamic analysis is then carried out from the induced volume heat source until the degradation temperature of the material is reached out. The study finally results in a one-dimensional model describing the optical and thermo-dynamical behavior of GFRP under high-power laser irradiations up to ignition of the chemical degradation phenomena.

Composite Materials and their Recycling

This paper presents an assessment of the growing use of Glass Fibre Reinforced Plastic and Carbon Fibre Reinforced Plastic composites in the automotive and marine industry through the decades to current use. This report investigates how legislation such as the End of Life of Vehicles (ELV) will force the automotive industry to prepare for end of life recycling and gauge their progress with the aid of reports from the Knowledge Transfer Network (KTN) and Stella Job, who is a Supply Chain and Environment Officer for the UK trade association Composites UK, outlining the process of pyrolysis and solvolysis, with the aid of informal industry interviews and a case study at a small British sports car manufacturer to consider the practical work required.

Study on Compression Molding of an Intercrossed Prepreg Glass Fiber-Reinforced Plastic

In this paper, a specimen of 80 × 80 × 3.8 mm dimensions is cut out from the prepreg intercrossed glass fiber-reinforced plastic (GFRP) and subjected to hot compression molding. The experimental flow front of the specimen is compared to the one predicted by the finite element method (FEM) based on the Galerkin method. Since the prepreg intercrossed GFRP composite is made of stacking plain weaved prepregs, the fibers’ entanglement prevents the specimen slip across the mold surface. It is shown that the flow results are strongly affected by the mold-specimen friction: the slip parameter α =100 used in the FEM flow analysis provides a close correlation of the calculated and experimental results.

Modelling of machining force in end milling of GFRP composites using MRA and ANN

Glass Fibre Reinforced Plastic (GFRP) composites show a tremendous increase in applications due to their superior properties. Some damages on the surface occur due to their complex cutting mechanics in cutting process. Minimization of the machining force is fairly important in terms of product quality. In this study, a GFRP composite material with 15°, 60° and 105° were milled to experimentally minimize the cutting forces on the machined surfaces, using solid carbide end mills with 25°, 35° and 45° helix angles at different combinations of cutting parameters. Experimental results showed that the machining force increased with increasing fibre orientation and feed rate; on the other hand, it was found that the machining force decreased with increasing cutting speed and helix angle of the end mill cutter. In addition, analysis of variance (ANOVA) results clearly revealed that the helix angle of the end mill cutter was the most influential parameter affecting the machining force in end milling of GFRP composites. A model based on an artificial neural network (ANN) is introduced to predict the machining force of GFRP with three different fibre orientations. This model is a feed forward back propagation neural network with a set of machining parameters as its inputs and the machining force as its output. Levenberg–Marquardt learning algorithm was used in predicting the machining force to reduce the number of expensive and time-consuming experiments. The highest performance was obtained by 4-18-18-1 network structure. ANN was notably successful in predicting the damage factor due to higher R2 and lower RMSE and MEP.

Nondestructive evaluation of hidden multi-delamination in a glass-fiber-reinforced plastic composite using terahertz spectroscopy

In this study, a terahertz time-domain spectroscopy (THz-TDS) imaging system was devised to detect hidden multi-delamination in a glass-fiber-reinforced plastic (GFRP) composite laminates. Shapes, thicknesses and locations in the z-direction of each delamination among the overlapped multi-delamination were analyzed considering the interaction between the pulsed THz wave and the GFRP composite. THz wave power and phase were discussed by the analytical calculations and the experimental results with the evaluation of hidden multi-delamination. Then, the THz image results were compared with those of the ultrasound wave inspection method. Finally, hidden multi-delamination in the GFRP composite laminate was successfully detected and imaged using the THz-TDS imaging system, showing that this system can be widely utilized to evaluate the reliability of composite structures as a nondestructive evaluation method.

Modelling and Analysis of Wear Prediction in Machining of Nano Based GFRP Composites Using RSM

Glass fiber reinforced composite material was fabricated using E-glass fiber with unsaturated polyester resin. In Glass Fiber Reinforced Plastic (GFRP) composites, the matrix of polymer is reinforced with glass fibers. The surface quality and dimensional precision significantly affect the parts during their suitable life, particularly in cases where the components come in contact with other elements or materials. In the current study, GFRP is machined with two cases i.e. with and without Nano combinations in lathe. These machining studies were carried out on lathe using three different cutting tools: namely Carbide (K-20), Cubic Boron Nitrate (CBN) and Polycrystalline Diamond (PCD). The cutting parameters considered were cutting speed, feed, and depth of cut. Surface Finish is the most important parameter measured by main spindle and compares the value with another. A second order mathematical model in terms of cutting parameters was developed using RSM. The results specify the developed model is suitable for prediction of surface roughness in machining of GFRP composites.

Effect of hybrid (micro- and nano-) fillers on impact response of GFRP composite

The impact behavior of hybrid nano-/micro-modified composite was investigated in Glass Fiber Reinforced Plastics (GFRP). The hybrid nano-/micro fillers chosen were Cloisite® 30B nanoclay and 3M™ Glass Bubbles iM16K. Impact testing at varying energy levels was performed using drop weight impact tests (DWIT). The impact response was evaluated in terms of damage progression by visual observations, evolution of the peak force and stiffness with corresponding absorbed energy. At high impact energy levels, pristine and Glass Bubble modified laminates showed the highest peak force and low absorbed energy with penetration of the impactor through their thickness, while nanoclay-modified laminate showed the highest absorbed energy and minimum peak reaction force without penetration. The hybrid laminate exhibited intermediate absorbed energy and peak reaction force sustained for longer time. Overall, the work demonstrated the ability to tailor composite properties for enhancement of impact performance by using various types, concentrations and configuration of nano/micro particles.

Improvement of impact-resistant property of glass fiber-reinforced composites by carbon nanotube-modified epoxy and pre-stretched fiber fabrics

Glass fiber-reinforced plastic composites (GFRPs) are often suffered to impact loadings; it is essential to improve its damage-resistant properties and understand the energy absorption mechanisms. In this work, the low-velocity impact behaviors of GFRPs were investigated in consideration of epoxy resins modified with 0, 0.4, and 0.75 % multi-walled carbon nanotubes (MWCNTs) by weight content and pre-stretched fabric at 0, 1.27, and 2.47 kg weight. In comparison with pure GFRPs sample, MWCNT-modified specimens are effective in improving the impact resistance under impact energies at 9, 16, and 22 J in terms of reduced damage factor and enhanced perforation threshold. Microscopic fractographic analysis indicated that the incorporation of MWCNTs in epoxy matrix offered additional mechanisms through breakage, bridging, and pull-out of carbon nanotubes to favor load transfer effect, prevent crack propagation, and thus dissipate more energy. The dynamic thermo-mechanical analysis proved that MWCNTs improved the storage modulus and glass transition temperature of the composites. In addition, the pre-stretched GFRP composites showed more impact resistant than the non-stretched ones through instant load transfer effect.

Analysis and optimisation of machinability behavior of GFRP composites using fuzzy logic

Purpose– Glass fibre reinforced plastics (GFRP) contain two phases of materials with drastically distinguished mechanical and thermal properties, which brings in complicated interactions between the matrix and the reinforcement during machining. Surface quality and dimensional precision will greatly affect parts during their useful life especially in cases where the components will be in contact with other elements or materials during their useful life. The purpose of this paper is to discuss the application of the Taguchi method with fuzzy logic to optimise the machining parameters for machining of GFRP composites with multiple characteristics.Design/methodology/approach– The machining tests were performed on a CNC milling machine using solid carbide (K10) End mill cutting tool with three different helix angles. Experiments were planned using Taguchi’s orthogonal array with the cutting conditions prefixed.Findings– The machining parameters, namely, helix angle of the end mill cutter, spindle speed, feed rate, depth of cut, and work piece fibre orientation (specially applied to the GFRP composites) were optimised with considerations of multiple response characteristics, including machining force, material removal rate, and delamination. The results from confirmation runs indicated that the determined optimal combination of machining parameters improved the performance of the machining process.Originality/value– Multi-response optimisation of machinability behaviour of GFRP composites using fuzzy logic has not been attempted previously.

Effect of Cutting Parameters on Delamination of Glass Fiber Reinforced Plastic (GFRP) in CNC Milling

Now-a-days glass fiber-reinforced plastics (GFRP) are always applicable in variety of engineering applications. It is used in aerospace, automotive and aircraft industries due to their well known properties. Milling of GFRP composite materials is very difficult due to its heterogeneity and the number of troubles like as surface delamination during machining affects uniqueness of the material and the machining parameters. Present paper focuses the experimental details to find out delamination factor on GFRP composite laminates by using Taguchi’s DOE L9 orthogonal array. The main objective of the present work is to optimize the process parameters in the drilling of GFRP composite using Taguchi DOE and to find the significance of each process parameter using ANOVA. As far as the effect of input factors are considered, the factors drilled material and spindle speed both have nearly predominant influence on the delamination factor of drilled holes on GFRP composite by using CNC milling process.

Mechanical Properties of a Hybrid Nanocomposite Under Room Temperature and Hot-Wet Environments

A thermosetting epoxy resin was hybrid modified by addition of 9 wt% of rubber micro-particles and 10 wt% of silica nanoparticles. Glass fiber reinforced plastic (GFRP) composite laminates employing the unmodified (GFRP-neat) and the hybrid modified (GFRP-hybrid) epoxy matrix was fabricated. Mechanical properties viz., tension, compression, Interlaminar shear strength, and flexure, were determined for these GFRP composites in both room temperature (RT) and in hot-wet (HW) conditions. All the mechanical tests were conducted following their respective ASTM test standard specifications. Prior to testing, HW specimens were hygrothermally aged until moisture absorption saturation was attained. The GFRP-hybrid composite absorbs moisture at a higher rate and saturates with higher moisture content than that by GFRP-neat composite. The hybrid modification of epoxy matrix of GFRP composite alters the mechanical properties in RT by about +6 to −12 % and in HW conditions by about +3 to −9 %, depending on the specific property. The degradation of mechanical properties due to moisture varies from about 0 to 23 % in both GFRP composites. Dramatic improvement of over 160 % in fracture toughness and over 400 % in fatigue life of GFRP-hybrid composite reported earlier, appear to more than compensate for minor alterations in other mechanical properties of this material.

Study on the impact of fiber length on the correlation of separation and orientation in flow molded glass fiber-reinforced plastic composites.

During the compression molding of fiber-reinforced plastic composites, there are two issues: one is separation of fiber and matrix because of the different flow state and fiber orientation. Due to separation and orientation, moldings become nonhomogeneous, and show anisotropy. Therefore, separation and orientation should be closely corresponded to molding condition and fiber structure. If fiber shows strong agglomeration, it increases the separation, but fiber orientation will be limited. That is, separation and orientation of fiber is closely related, and the relationship should be clearly defined. In this study, fiber content and length is varied for stacked laminates, and primary sheet is fabricated with thermal compression press. Primary sheet is heated and molded with 30-ton hydraulic press. Nonhomogeneity, one of indicators for separation, is measured from one-dimensional rectangular plate after compression. Orientation function is calculated using X-ray image on moldings and image scanner for processing imagery data. From the correlation between the separation and the orientation of fiber and matrix, the correlation coefficient is defined, and the impact of fiber length on the coefficient is evaluated.

Numerical optimization of hole making in GFRP composite using abrasive water jet machining process

Machining of composite materials for the production of bolt holes is essential in the assembly of the structural frames in many industrial applications of glass fiber-reinforced plastic (GFRP). Abrasive water jet cutting technology has been used in industry for such purposes. This technology has procured many overlapping applications and as the life of the joint in the assembled structure can be critically affected by the quality of the holes, so it is important for the industry to understand the application of the abrasive water jet cutting process on GFRP composite materials. The aim of the present work is to assess the influence of abrasive water jet machining parameters on the hole making process of woven-laminated GFRP material and to find the optimum values of the process parameters. Statistical approach was used to understand the effects of the predicted variables on the response variables. Analysis of variance was performed to isolate the effects of the parameters affecting the hole making in abrasive water jet cutting. The results show that the optimum values of cutting feed, fiber density, water jet pressure, standoff distance, and abrasive flow rate upon the response variables are 0.3 m/min, 0.82 g/cm3, 150 MPa, 2 mm, and 100 g/min, respectively.

Mechanical properties and production quality of hand-layup and vacuum infusion processed hybrid composite materials for GFRP marine structures

Glass Fiber Reinforced Plastic (GFRP) structures are primarily manufactured using hand lay-up or vacuum infusion techniques, which are cost-effective for the construction of marine vessels. This paper aims to investigate the mechanical properties and failure mechanisms of the hybrid GFRP composites, formed by applying the hand lay-up processed exterior and the vacuum infusion processed interior layups, providing benefits for structural performance and ease of manufacturing. The hybrid GFRP composites contain one, two, and three vacuum infusion processed layer sets with consistent sets of hand lay-up processed layers. Mechanical properties assessed in this study include tensile, compressive and in-plane shear properties. Hybrid composites with three sets of vacuum infusion layers showed the highest tensile mechanical properties while those with two sets had the highest mechanical properties in compression. The batch homogeneity, for the GFRP fabrication processes, is evaluated using the experimentally obtained mechanical properties.

Investigation of the Machinability Characteristics of GFRP / Epoxy Composites Using Taguchi Methodology

Many glass fiber reinforced plastic (GFRP) composite components made from primary melt processes require additional machining to meet the requirements of assembly and accurate dimensional tolerances. Importance of woven fabric based glass fibre reinforced composites is widely known in many industrial applications. However, very little is known about machinability of these composites. Cutting force is treated as one of the primary measures for determining the machinability of any material.This paper presents an investigation into the longitudinal turning of woven fabric and epoxy based GFRP composites, using polycrystalline diamond tool, so as to analyze the effect of cutting parameters and insert radius on the cutting force. The force was measured through longitudinal turning, according to the experimental plan, as developed on the basis of Taguchi methodology. The signal to noise ratio and analysis of variance were applied to the experimental data, in order to determine the effect of the process variables on tangential cutting force. Statistical results indicated that the cutting force is significantly influenced (at a 95% confidence level) by feed rate, followed by depth of cut, whereas, cutting speed and insert radius have a smaller influence. The cutting force also increases with the increase in feed rate and depth of cut.

Multi-objective optimisation of CNC milling process using Grey-Taguchi method in machining of GFRP composites

Purpose – In milling process the surface roughness and delamination are the most important performance characteristics, which are influenced by many factors like fibre orientation angle, helix angle, feed rate and spindle speed. The selection of these parameters at optimum level plays a vital role in getting minimum surface roughness and delamination factor. The purpose of this paper is to present multi-objective optimisation of Computer Numerical Control milling parameters using Grey-Taguchi method to get minimum surface roughness and delamination factor in machining of glass fibre reinforced plastics (GFRP) composites used in automotive, aircraft and manufacture of space ships. Design/methodology/approach – The experiments are designed and conducted based on Taguchi's L27 orthogonal array by taking fibre orientation angle, helix angle, feed rate and spindle speed at three levels and responses are surface roughness and delamination factor. Taguchi's signal-to-noise (S/N) ratio are determined based on their performance characteristics. A Grey relation grade is obtained by using S/N ratio. Based on Grey relational grade value, optimum levels of parameters have been identified by using response table and response graph. Findings – Optimum levels of parameters for GFRP composites have been identified by using response table and response graph and the significant contributions of controlling parameters are estimated using analysis of variance. Originality/value – The combined effect of fibre orientation angle and helix angle during milling of GFRP composites using Grey relational analysis has not been previously attempted for analysis.