Fiber Reinforced Plastic Composites Research Articles

Surface grinding of carbon fiber–reinforced plastic composites using rotary ultrasonic machining: Effects of tool variables

Carbon fiber–reinforced plastic composites have many superior properties, including low density, high strength-to-weight ratio, and good durability, which make them attractive in many industries. However, due to anisotropic properties, high stiffness, and high abrasiveness of carbon fibers in carbon fiber–reinforced plastic, high cutting force, high tool wear, and high surface roughness are always caused in conventional machining processes. This article reports an investigation using rotary ultrasonic machining in surface grinding of carbon fiber–reinforced plastic composites in order to develop an effective and high-quality surface grinding process. In rotary ultrasonic machining surface grinding of carbon fiber–reinforced plastic composites, tool selection is of great importance since tool variables will significantly affect output variables. In this work, the effects of tool variables, including abrasive size, abrasive concentration, number of slots, and tool end geometry, on machining performances, including the cutting force, torque, and surface roughness, are experimentally studied. The results show that lower cutting forces and torque are generated by the tool with higher abrasive size, lower abrasive concentration, and two slots. Lower surface roughness is generated by the tool with smaller abrasive size, smaller abrasive concentration, two slots, and convex end geometry. This investigation will provide guides for tool selections during rotary ultrasonic machining surface grinding of carbon fiber–reinforced plastic composites.

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.

Flow-compacted deformations coupled with thermo-chemically induced distortions in manufacturing of thick unidirectional carbon fiber reinforced plastics composites

A novel technique to predict the manufacturing process-induced distortions and deformations in thick unidirectional carbon fiber reinforced plastics laminates is detailed in this article. An integrated numerical model is developed to account for non-isothermal resin flow, related compaction, transient resin cure, and resin shrinkage effects to predict the final shape of the autoclave cured thick prepreg laminate. The associated physics are mathematically coupled to solve for the process variables interactively. The results illustrate reduction in the thickness of the laminate prior to the start of curing when initial fiber volume fractions are pre-set. This confirms that the initial transverse deformation of B-stage prepreg is due to the applied vacuum and/or pressure. Once curing initiates, deformation of the laminate due to compaction increases, proportionally, with the increase in fiber volume fraction. Furthermore, the thermo-chemical residual strains contribute to additional compaction. The final distorted shape observed in simulation of the originally flat laminate matches with the shape of the fabricated laminate with 6.6 mm thickness. A solution to minimize the distortion is discussed in detail. This procedure is extended to simulate a curved laminate’s processing; where, the shear moduli were observed to influence the final shape of the laminate. The findings are presented and deliberated in this article.

Additive manufacturing of carbon fiber-reinforced plastic composites using fused deposition modeling: Effects of process parameters on tensile properties

Carbon fiber-reinforced plastic composites have been intensively used for many applications due to their attractive properties. The increasing demand of carbon fiber-reinforced plastic composites is driving novel manufacturing processes to be in short manufacturing cycle time and low production cost, which is difficult to realize during carbon fiber-reinforced plastic composites fabrication in common molding processes. Fused deposition modeling, as one of the additive manufacturing techniques, has been reported for fabricating carbon fiber-reinforced plastic composites. The process parameters used in fused deposition modeling of carbon fiber-reinforced plastic composites follow those in fused deposition modeling of pure plastic materials. After adding fiber reinforcements, it is crucial to investigate proper fused deposition modeling process parameters to ensure the quality of the carbon fiber-reinforced plastic parts fabricated by fused deposition modeling. However, there are no reported investigations on the effects of fused deposition modeling process parameters on the mechanical properties of carbon fiber-reinforced plastic composites. In the experimental investigations of this paper, carbon fiber-reinforced plastic composite parts are fabricated using a fused deposition modeling machine. Tensile tests are conducted to obtain the tensile properties. The effects of fused deposition modeling process parameters on the tensile properties of fused deposition modeling-fabricated carbon fiber-reinforced plastic composite parts are investigated. The fracture interfaces of the parts after tensile testing are observed by a scanning electron microscope to explain material failure modes and reasons.

An optical method for measuring surface roughness of machined carbon fibre-reinforced plastic composites

Characterization of the damage induced by machining of fibre-reinforced composites is usually performed by measuring surface roughness. Contact-based surface profilometers are the most used equipment in industry; however, it has been found that there are performance limitations which may result when used to measure machined heterogeneous composite surfaces. In this research, surface roughness is characterised using a commercial non-contact optical method, and compared with a conventional stylus profilometer. Unidirectional and multidirectional carbon fibre laminates were edge trimmed and slot milled. The variation in surface roughness was compared using different tool types, fibre orientations and cutting parameters. Surface damage and cutting mechanisms were assessed by using scanning electron microscope images, and the suitability of roughness parameters were also analysed including: Sa, Skewness and Kurtosis. Using the optical system allowed accurate roughness calculation of individual plies on a multidirectional laminate with different fibre orientations. The research has also shown that the optical system, including the use of areal roughness parameters, can increase the accuracy of roughness measurement for machined fibrous composite surfaces and is less sensitive to measurement position than the stylus.

A fatigue damage meso-model for fiber-reinforced composites with stress ratio effect

This work presents a fatigue damage meso-model for fiber-reinforced plastic composites, in which the effect of stress ratios on the off-axis fatigue behavior is taken into account. The non-dimensional effective stress concept is introduced in the continuum damage mechanics method. Damage growths and fatigue failure are studied along axial, transverse and shear directions at meso-scale level. The proposed model is validated through numerical simulations that describe the meso fatigue damage accumulation and the fatigue life for off-axis unidirectional fiber-reinforced plastic composite laminates of arbitrary fiber orientation under different stress ratios. It is shown that the fatigue damage behavior and fatigue life for off-axis unidirectional glass/epoxy and carbon/epoxy composite laminates are adequately described by the proposed fatigue model over the range of different stress ratios.

Effects of fiber orientation angles of fiber-reinforced plastic on sand solid particle erosion behaviors

Solid particle erosion in industrial applications has been a serious problem in many engineering fields. Earlier studies on fiber-reinforced plastic (FRP) composites were mainly focusing on the erosive wear behavior at several different impact angles. However, the effect of fiber orientation on FRP composites has not been thoroughly investigated. Since fiber orientation is one of the important factors in which causing erosive wear damages to FRP composites, in order to understand the virtue of this problem, it is important to investigate the effect of fiber orientation at different impact angles. In this research, the effect of fiber orientation of unidirectional fiber-reinforced plastic composites on erosive wear behavior was studied. Sandblasting-type erosion tests were conducted on the FRP composites with fiber orientation ranging at three impact angles to clarify the relation between fiber orientation and erosive wear behavior. The Dyneema fiber (ductile material) and the carbon fiber (brittle material) were used for the reinforcement fiber in FRP. From the result, it is confirmed that CFRP composites with higher fiber orientation angle erode faster than the composites with lower fiber orientation angle. But the erosion characteristic of DFRP was almost the same regardless of the fiber orientation angle. The damaged surfaces of the FRP composites were then analyzed using scanning electron microscopy and the possible erosion wear mechanisms were investigated.

Inter-laminar delamination analyses of Spar Wingskin Joints made with flat FRP composite laminates

3D Finite Element Analyses have been carried out for Spar Wingskin Joints made with laminated Graphite Fibre Reinforced Plastic composites subjected to uniformly distributed transverse load. The delamination has been pre-embedded at the most likely location, i.e. in resin layer between the top and next ply of the fibre reinforced plastic laminated wingskin and near the spar overlap end. Multi-Point Constraint finite elements have been made use of at the vicinity of the delamination fronts. This helps in simulating the growth of the embedded delamination at both ends. The inter-laminar peel and shear stresses responsible for causing delamination damage have been evaluated. Strain energy release rate components corresponding to the Mode I (opening), Mode II (sliding) and Mode III (tearing) of delamination are determined using the principle of Virtual Crack Closure Technique. These are seen to be different and non-self-similar at the two fronts of the embedded delamination. Mode I Strain energy release rate (GI) primarily governs the process of delamination propagation.

Compression-induced graphite nanoplatelets orientation in fibre-reinforced plastic composites

We demonstrate a facile and general technique for the orientation of nanoplatelet fillers dispersed in adhesives for tensile strength enhancement of compressed fibre-reinforced plastic (FRP) composites. Polyurethane adhesives filled with a selected exfoliated graphite nanoplatelet (MexGnP-8) powder at concentration range of 0–0.75 wt% were prepared. The same adhesives were used to fabricate compressed FRP composites in which the mechanical properties were assessed and found to be inconsistent with the findings from the tests conducted on uncompressed FRP composites and the filled adhesives. Only the polyurethane adhesive filled with 0.25 wt% MexGnP-8 had tensile strength higher than that of the neat adhesive, and the uncompressed FRP composites have similar results. However, all the compressed FRP composites fabricated with the polyurethane adhesive filled with MexGnP-8 between the concentration range of 0–0.75 wt% had greater tensile strengths than the compressed FRP fabricated with the neat adhesive. Compression has been found to induce orientation of MexGnP-8 and resulted in tensile strength enhancement in the FRP.

Mechanical properties of nano titanium oxide particles - hybrid jute-glass FRP composites

Fiber reinforced plastics (FRP) are composite materials made of plastics reinforced with fibers. Fiber reinforced plastics find increased applications in automotive, marine, aerospace and construction industries. The objective of the present work is to study the effect of nano titanium oxide fillers on the properties of hybrid jute-glass FRP composites. In the present work, nano titanium oxide particles - hybrid jute-glass FRP composites were manufactured with glass fiber chopped strand mat, woven jute mat, polyester resin and nano titanium oxide fillers by the hand layup method. The nano titanium oxide fillers were incorporated in different weight ratios in the fiber reinforced plastics and the mechanical properties were evaluated.

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.

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.

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.

Fabrication and characterization of bamboo fiber- reinforced polyethylene-polystyrene composites using glycerol as plasticizer

<p>Fiber-reinforced polymer composites are composed of a polymer matrix (PE-PS) combined with a fiber (bamboo fibers) to provide conspicuous reinforcement. In light of recycling plastic and natural fibers, the research aim to fabricate and characterize bamboo fiber-reinforced polyethylene-polystyrene composites using glycerol as plasticizer. Specifically, the study investigated the effect on the physical and mechanical properties and water absorption of the composites by varying the following parameters: substitution of glycerol instead of the usual cooking oil in fabrication of DRM, and bamboo fiber loading. Using 1:3 PE-PS ratio, glycerol incorporation was done in DRM by melting together plastic and styrofoam wastes using a densifying machine at 150˚C. DRM samples with 70% (w/w) glycerol incorporation were then compared to the original DRM samples with 70% (w/w) cooking oil. The modified DRM were then loaded with 1, 2 and 3% bamboo fiber-reinforcement using a two-roll mill at 200˚C and compression molding machine at 200˚C and 50 kg/cm2 for 5 mins in the aluminium mold. The composites were characterized by Universal Testing Machine (tensile strength) following the ASTM standard D638. In addition, water absorption of the fabricated composites was tested using the standard method specified by ASTM D570.The bamboo fiber-reinforced polyethylene-polystyrene composites at 1:3 PE: PS ratio rendered better tensile strength and less water absorbed using 70% (w/w) glycerol as plasticizer and at 1% bamboo fiber loading. For future studies, it is recommended to study the impact of different parameters (glycerol percentage, time, temperature, pressure, fiber type and dimensions, fiber extraction, etc.) in the fabrication of the fiber-reinforced recycled plastic composites. Other characterizations of the fabricated plastic composite including thermal properties, leaching and biodegradation experiments and compressive and flexural strengths can also be done.</p><p>Keywords: Fiber-reinforced polymer, plasticizer, composites.</p>

Driving scaleable solutions for fiber-reinforced plastic surface preparation

The lightweight and high strength of glass and carbon fiber-reinforced plastic composites (FRPs) have been exploited in a wide range of engineering applications from aircraft wings and wind turbine blades to monocoques in racing cars. In recent years the automotive sector has focussed heavily on the integration of lightweight materials into vehicle design in light of the legislation for low carbon emissions and improved fuel economy. Issues surrounding how the manufacture and processing of these materials can be adapted for a volume production environment are currently hurdles that must be overcome if mass adoption is to become a reality.

Impact of stacking sequence on tribological wear performance of woven jute-glass hybrid epoxy composites

Natural fibre-reinforced plastic (FRP) composites have gained much interest because of their environment friendliness and cost-effectiveness compared to synthetic fibre-reinforced composites. The availability of natural fibre and ease of manufacturing have tempted researchers worldwide to develop a locally available low-cost fibre and study their feasibility for reinforcement purposes and to what extent they can satisfy the required specifications of well-reinforced polymer composite for tribological application. FRP composites have various applications in the automobile, aerospace and marine fields. They are applied to inlet cone, fan exit guide vanes and other parts of structures in a turbofan engine for lightening an engine. The erosion characteristics of the FRP composites are of vital importance due to the operational requirements in dusty environments. In this present work, the impact of stacking sequence on erosion wear behaviour of untreated woven jute and glass fabric-reinforced epoxy hybrid composites has been investigated experimentally. The orientation of glass and jute fabric was kept at (0°–90°) and (45°–45°) for all stacking sequences. All the laminates were prepared using four plies, and, the number and position of glass layers were varied so as to obtain four different stacking sequences. The erosion rate of these composites were evaluated at different impingement angles (30°–90°) at three different impact velocities (V = 48, 70, 82 m/s). Silica sand was used as the erodent. Our results showed that the impingement angle had a significant influence on the erosion rate. The composite materials showed semi-ductile behaviour with the maximum erosion at an impingement angle of 60°. The morphologies of the eroded surface were observed by a scanning electron microscope, and the possible erosion mechanisms were discussed.

Optimizing the Performance of Natural Fiber Reinforced Plastics Composites: Influence of Combined Optimization Paths on Microstructure and Mechanical Properties

This study investigated the combination of two different optimization paths (phase compatibilization and manufacturing process optimization) on the microstructure (fiber dimensions, matrix crystallinity and matrix molecular properties) and mechanical properties (flexural and tensile moduli, impact strength, and tensile stress at yield) of flax fiber/postconsumer recycled plastic composites. A two-step optimization methodology was adopted. First, the material composition was optimized by phase compatibilization using maleic anhydride grafted polypropylene (MAPP) and maleic anhydride grafted ethylene octene metallocene copolymer (EO-g-MAH) as additives. Then, the manufacturing process (extrusion followed by injection) was optimized in terms of temperature profile and screw speed for extrusion, as well as barrel temperature profile, mold temperature, injection speed, injection pressure, injection time and back pressure for injection. The results showed that, besides good fiber-matrix interfacial adhesion, the combination of both optimization paths promoted an optimum balance between components degradation and composite homogeneity (good fiber and additives dispersion in the matrix), leading to better mechanical properties. It is shown that this optimization procedure was able to improve all the mechanical properties of the composites, as well as being effective in terms of performance and costs.

Evaluation of porosity effects on the mechanical properties of carbon fiber-reinforced plastic unidirectional laminates by X-ray computed tomography and mechanical testing

The effects of porosity on the matrix-dominated mechanical properties of unidirectional carbon fiber-reinforced plastic composites were evaluated using X-ray computed tomography and mechanical testing. Carbon fiber-reinforced plastic plates of four porosity levels were manufactured by implementing different curing cycles. Porosity was detected by X-ray computed tomography tests, conducted on samples taken from the plates, and quantified by analyzing the computed tomography scans using the VGStudio Max software. Four different types of mechanical tests were conducted; namely, transverse tension, V-notched rail shear, three-point bending, and short-beam shear tests. The porosity analysis showed that with increasing the porosity volume fraction, the number of pores decreases, their volume increases while their shape changes from spherical or ellipsoidal to a needle-shape. The results from mechanical tests reveal that the presence of pores reduces all matrix-dominated material properties of the UniDirectional (UD) carbon fiber-reinforced plastic material. The reduction in strength is greater than the reduction in the elastic properties. Moreover, the reduction in the in-plane shear and interlaminar properties is greater than the tensile properties of the UD carbon fiber-reinforced plastic material. Between porosity contents of similar volume fraction, the one with the few large pores proved more severe than the one with the many small pores. The large standard deviation observed for some of the tests is attributed to the non-uniform dispersion of pores.

Characterization of Glass Fibre/Carbon Fibre Hybrid Thermoplastics Composite Laminates Fabricated by Film Stacking Method

The Fibre Reinforced Plastic (FRP) composites are extensively used for a wide variety of applications in automobile, aerospace, chemical, biomedical and civil engineering fields due to their excellent properties. Composite materials offer significant advantages in strength-to-weight ratio and corrosion resistance over metallic materials. Initially FRP composites were based mainly on thermoset polymers because of the ease of manufacturing. But, recently FRP composites using thermoplastics matrices are gaining importance because of their advantages over thermoset composites. In the present work, FRP laminates were fabricated using glass fabric and carbon fabric as reinforcements and thermoplastic polymer (polypropylene) as matrix. Fiber Reinforced Thermoplastics (FRTP) laminates of glass fibre /polypropylene (GF/PP), carbon fibre/ polypropylene (CF/PP) and glass-carbon fibre /polypropylene (GF/CF/PP) hybrid composite laminates were fabricated by film stacking method using hot compression molding press under optimum process parameters (pressure, temperature and dwell time). The fabricated FRTP laminates were tested for various mechanical and physical properties viz., tensile strength/modulus, flexural strength/modulus, izod impact strength, moisture absorption, barcol hardness and density as per relevant ASTM standards. The results of the tests carried out on three materials were compared. It was observed that hybrid laminate (GF/CF/PP) is superior in flexural strength/modulus as compared to GF/PP but the little lower mechanical properties compared to CF/PP laminates. But use of hybrid laminates has great cost advantage compared to CF/PP.