The effect carbon nanotube on three-point bending behavior of fiber reinforced composite

71-79The aim of this research article has been to show the effect of Carbon Nanotube (CNT) additive on the performance of composite plate materials with fiber reinforced polymer matrix produced by vacuum infusion method under bending test. In this study, multiple layered composite plates have produced by glass, carbon, and aramid fiber reinforcements with 0.5% CNT addition by mass. In addition, a hybrid composite plate containing glass, carbon and aramid (Kevlar) fiber has produced with CNT addition by using the same production parameters. Three point bending test has performed on the composite plates under 1 mm/min bending with ASTM D7264 standard. As a result, CNT addition has increased the flexural performance but has decreased the elongation of glass and carbon fiber reinforced systems. In aramid reinforced system, both flexural strength and elongation has increased. However, in the hybrid fiber reinforced system, different fiber types have damaged at different elongation distances within the structure under different loads, and gradually more than one failure have observed. When the CNT has added to the hybrid system, the elongation increased but the flexural strength has decreased

Ballistic impact behaviour of glass fibre reinforced polymer composite with 1D/2D nanomodified epoxy matrices

In this paper, experimental studies on the ballistic impact behaviour of nanomodified glass fibre-reinforced polymer (GFRP) are reported. The epoxy matrix of the GFRP was modified by the addition of graphene platelets (GNPs), carbon nanotubes (CNTs), combined hybrid hexagonal boron nitride nanosheets (BNNS)/CNT, and combined boron nitride nanotubes (BNNTs)/GNPs nanoparticles. Ballistic impact tests were carried out on GFRP laminates at two projectile velocities of 76 ± 1 m s−1 for full-field deformation measurements and 134.3 ± 1.7 m s−1 for perforation tests. The behaviour of the plates during impact was recorded using digital image correlation (DIC), in order to monitor strain and out-of-plane deformation in panels with nanoreinforced matrices. Following penetrative impact tests, pulse thermography was used to characterise the delamination of impacted plates. The results of full-field deformation, exit velocity and energy absorption measurements from the ballistic tests show significant improvements in impact resistance for the panels made from nanomodified epoxies relative to laminates with the unmodified epoxy matrix. The highest absolute absorbed energy was observed for the GFRP panels fabricated using the epoxy matrix loaded with BNNT/GNP at 255.7 J, 16.8% higher than the unmodified epoxy matrix

On the extent of fracture toughness transfer from 1D/2D nanomodified epoxy matrices to glass fibre composites

Abstract: In this study, the effects of adding nanofillers to an epoxy resin (EP) used as a matrix in glass fibre-reinforced plastic (GFRP) composites have been investigated. Both 1D and 2D nanofillers were used, specifically (1) carbon nanotubes (CNTs), (2) few-layer graphene nanoplatelets (GNPs), as well as hybrid combinations of (3) CNTs and boron nitride nanosheets, and (4) GNPs and boron nitride nanotubes (BNNTs). Tensile tests have shown improvements in the transverse stiffness normal to the fibre direction of up to about 25% for the GFRPs using the ‘EP + CNT’ and the ‘EP + BNNT + GNP’ matrices, compared to the composites with the unmodified epoxy (‘EP’). Mode I and mode II fracture toughness tests were conducted using double cantilever beam (DCB) and end-notched flexure (ENF) tests, respectively. In the quasi-static mode I tests, the values of the initiation interlaminar fracture toughness, GICC, of the GFRP composites showed that the transfer of matrix toughness to the corresponding GFRP composite is greatest for the GFRP composite with the GNPs in the matrix. Here, a coefficient of toughness transfer (CTT), defined as the ratio of mode I initiation interlaminar toughness for the composite to the bulk polymer matrix toughness, of 0.68 was recorded. The highest absolute values of the mode I interlaminar fracture toughness at crack initiation were achieved for the GFRP composites with the epoxy matrix modified with the hybrid combinations of nanofillers. The highest value of the CTT during steady-state crack propagation was ~ 2 for all the different types of GFRPs. Fractographic analysis of the composite surfaces from the DCB and ENF specimens showed that failure was by a combination of cohesive (through the matrix) and interfacial (along the fibre/matrix interface) modes, depending on the type of nanofillers used

Composite materials for wind energy applications

Weight and strength of materials are important in design for wind energy and aerospace industries. It is a major advance to design new materials for these kinds of applications to achieve high efficiency reducing weight. Sandwich composites and Fibre Metal Laminates (FMLs) are outstanding materials owing to superior mechanical properties. However, they need to be evaluated under static and dynamic loading to which these kinds of applications are subjected. The purpose of the thesis is the investigation of sandwich composite and FMLs for wind turbine blade and aerospace structure evaluating Digital Image Correlation (DIC) and modelling of sandwich composites and FMLs to provide an insight into the failure processes in these materials. In this thesis, sandwich composites with four different core materials and five different surface finishing options were studied. There are advantages in having a softer core near the outer surface to improve impact and mechanical performance and grooves in the core are used to improve resin infusion and draping for curved structures. For the sandwich composites investigated, PVC and PET foam cored sandwich composites can be a substitute foam core material especially for wind turbine blades instead of using balsa cored sandwich composite. In addition, saw-cut (foam is partially cut) and flexi-cut (with grooves on both sides) are surface finishing options often employed to improve the energy absorption and increase the flexural behaviour in a beneficial way. The behaviour of curved sandwich composites was also assessed. In addition, FMLs with three different metal and three different design configurations have been evaluated. The most important parameter for the FMLs are the thickness when considering flexural and impact response of the FMLs. Both of these studies can be guidelines for designing materials for wind turbine blade and aerospace applications to decrease structure weight and increase the mechanical strength of the structure.Open Acces

The Effect Carbon Nanotube on Three-point Bending Behavior of Fiber Reinforced Composite

The aim of this research article is to show the effect of Carbon Nanotube (CNT) additive on the performance of composite plate materials with fiber reinforced polymer matrix produced by vacuum infusion method under bending test. In this study, composite plates with carbon fiber, glass fiber and Kevlar fiber reinforced polymer matrix with similar fabric weave structures were produced with the same production parameters. The same composite structures were reproduced as a hybrid composite structure with 0.5% CNT reinforcement by mass. Since CNT is thought to have different effects on different fiber types, in addition to the study, a hybrid composite plate containing glass, carbon and kevlar fiber was produced in two different ways, CNT reinforced and without reinforcement, using the same production parameters. Three point bending test was performed on glass, carbon, kevlar and hybrid structure fiber reinforced composites under 1 mm/min bending with ASTM D7264 standard. As a result, with CNT addition bending performance increased in glass and carbon fiber reinforced composite structures, but elongation performance decreased. In kevlar, both flexural strength and elongation increased. In the hybrid fiber reinforced structure, different fiber types were damaged at different elongation distances within the structure under different loads, and gradually more than one breaks was observed, and when CNT is added, it let flexural strength decreased but elongation increased

Impact Performance Improvement of Multiscale Hybrid Fiber Reinforced Polymer Composites with CNT

Improving the interface properties of carbon nanotubes increases the mechanical performance of fiber-reinforced polymer matrix composites. Studies on different fiber types and different polymer matrix materials present promising results in literature. The effect of carbon nanotube (CNT) additives on impact performance of fiber reinforced polymer matrix composites produced by vacuum infusion method and drop weight impact test applied. Glass and carbon 1 m2 fiber fabrics were divided into 9 equal square pieces and placed on top of each other to make them multi-layered structure. Fiber reinforcements were produced using vacuum infusion method with epoxy resin. 0.5% of the total composite weight was added to CNT with same production parameters and intraply hybrid composite containing glass, carbon and aramid fibers was also produced. Samples were produced from the composite plates and the drop weight impact test was performed with 50 J impact energy in accordance with ASTM D7136 standard. While this increase could be observed in glass fiber and carbon fiber reinforced composites, the impact energy absorption performance in carbon fiber reinforced composite increased more than 100%. CNT increased the impact performance of multi-layer fiber reinforced polymer matrix composites

Impact Performance Improvement of Multiscale Hybrid Fiber Reinforced Polymer Composites with CNT

Improving the interface properties of carbon nanotubes increases the mechanical performance of fiber-reinforced polymer matrix composites. Studies on different fiber types and different polymer matrix materials present promising results in literature. The effect of carbon nanotube (CNT) additives on impact performance of fiber reinforced polymer matrix composites produced by vacuum infusion method and drop weight impact test applied. Glass and carbon 1 m2 fiber fabrics were divided into 9 equal square pieces and placed on top of each other to make them multi-layered structure. Fiber reinforcements were produced using vacuum infusion method with epoxy resin. 0.5% of the total composite weight was added to CNT with same production parameters and intraply hybrid composite containing glass, carbon and aramid fibers was also produced. Samples were produced from the composite plates and the drop weight impact test was performed with 50 J impact energy in accordance with ASTM D7136 standard. While this increase could be observed in glass fiber and carbon fiber reinforced composites, the impact energy absorption performance in carbon fiber reinforced composite increased more than 100%. CNT increased the impact performance of multi-layer fiber reinforced polymer matrix composites

Effects of the core density on the quasi-static flexural and ballistic performance of fibre-composite skin/foam-core sandwich structures

Polymeric foams are extensively used as the core materials in sandwich structures and the core material is typically bonded between relatively thin fibre-composite skins. Such sandwich structures are widely used in the aerospace, marine and wind-energy industries. In the present work, various sandwich structures have been manufactured using glass-fibre-reinforced polymer (GFRP) skins with three layers of poly(vinyl chloride) foam to form the core, with the densities of the foam layers ranging from 60 to 100 kg/m3. This study has investigated the effects on the quasi-static flexural and high-velocity impact properties of the sandwich structures of: (a) the density of the polymeric-foam core used and (b) grading the density of the foam core through its thickness. The digital image correlation technique has been employed to quantitatively measure the values of the deformation, strain and onset of damage. Under quasi-static three-point and four-point bend flexural loading, the use of a low-density layer in a graded-density configuration reduced the likelihood of failure of the sandwich structure by a sudden force drop, when compared with the core configuration using a uniform (i.e. homogenous) density layer. The high-velocity impact tests were performed on the sandwich structures using a gas-gun facility with a compliant, high-density polyethylene projectile. From these impact experiments, the graded-density foam core with the relatively low-density layer located immediately behind the front (i.e. impacted) GFRP skin was found to absorb more impact energy and possess an increased penetration resistance than a homogeneous core structure