Fuzzy Fiber Reinforced Composite Research Articles

The effect of fuzzy fiber-reinforced composite skin on bending stiffness and debonding growth between skin and polymeric foam core of sandwich structures

Progressive innovations in the field of nanotechnology demonstrate that through the radial growth of aligned carbon nanotubes (CNTs) on the circumferential surfaces of fibers known as fuzzy fibers, the transverse elastic properties of fiber-reinforced composites are notably improved. The main objective of the present work is to numerically examine the effects of using fuzzy fiber-reinforced composite (FFRC) skins on the flexural behavior of sandwich structures. Based on the considered two-stage analysis, in the first instance, the mechanical properties of FFRC are determined by the simplified unit cell (SUC) micromechanical model. Afterward, by simulating the three-point bending test via the finite element method (FEM), major assessments are accomplished to reflect the effects of microstructure-level features, including fiber and CNT volume fractions, CNT/polymer interphase, and CNT diameter, on the bending stiffness and debonding growth between the FFRC skin and polyvinyl chloride (PVC) foam core. The results reveal the satisfactory influence of employing FFRC skins on improving the flexural behavior of sandwich structures.

Control of large amplitude vibrations of doubly curved sandwich shells composed of fuzzy fiber reinforced composite facings

This paper is concerned with the analysis of active constrained layer damping (ACLD) of geometrically nonlinear vibrations of doubly curved sandwich shells with facings composed of fuzzy fiber reinforced composite (FFRC). FFRC is a novel composite where the short carbon nanotubes (CNTs) which are either straight or wavy are radially grown on the periphery of the long continuous carbon fiber reinforcements. The plane of waviness of the CNTs is coplanar with the plane of carbon fiber. The constraining layer of the ACLD treatment is composed of the vertically/obliquely reinforced 1–3 piezoelectric composites (PZCs) while the constrained viscoelastic layer has been sandwiched between the substrate and the PZC layer. The Golla–Hughes–McTavish (GHM) method has been implemented to model the constrained viscoelastic layer of the ACLD treatment in time domain. A three dimensional finite element (FE) model of smart doubly curved FFRC sandwich shells integrated with ACLD patches has been developed to investigate the performance of these patches for controlling the geometrically nonlinear vibrations of these shells. This study reveals that the performance of the ACLD patches for controlling the geometrically nonlinear vibrations of the doubly curved sandwich shells is better in the case of the facings composed of laminated FFRC than that in the case of the facings made of conventional orthotropic laminated composite. The research carried out in this paper brings to light that even the wavy CNTs can be properly utilized for attaining structural benefits from the exceptional elastic properties of CNTs.

Active damping of geometrically nonlinear vibrations of sandwich plates with fuzzy fiber reinforced composite facings

This paper is concerned with the analysis of active constrained layer damping (ACLD) of geometrically nonlinear vibrations of sandwich plates with facings composed of fuzzy fiber reinforced composite (FFRC). FFRC is a novel composite where the short carbon nanotubes (CNTs) which are either straight or wavy are radially grown on the periphery of the long continuous carbon fiber reinforcements. The plane of waviness of the CNTs is coplanar with the plane of carbon fiber. The constraining layer of the ACLD treatment is composed of the vertically/obliquely reinforced 1–3 piezoelectric composites (PZCs) while the constrained viscoelastic layer has been sandwiched between the substrate and the PZC layer. The Golla–Hughes–McTavish method has been implemented to model the constrained viscoelastic layer of the ACLD treatment in time domain. A three dimensional nonlinear finite element model of smart FFRC sandwich plates integrated with ACLD patches has been developed to investigate the performance of these patches for controlling the geometrically nonlinear vibrations of these plates. This study reveals that the performance of the ACLD patches for controlling the geometrically nonlinear vibrations of the sandwich plates is better in the case of the facings composed of laminated FFRC than that in the case of the facings made of conventional orthotropic laminated composite. Particular emphasis has been placed on investigating the effect of the variation of piezoelectric fiber orientation angle on the performance of the ACLD treatment. The research carried out in this paper brings to light that even the wavy CNTs can be properly utilized for attaining structural benefits from the exceptional elastic properties of CNTs.

Effect of carbon nanotube waviness on active damping of laminated hybrid composite shells

In this article, we investigate the effect of carbon nanotube (CNT) waviness on the active constrained layer damping (ACLD) of the laminated hybrid composite shells. In particular, the effect of CNT waviness has been studied for the case of a novel nano-tailored composite—continuous fuzzy fiber-reinforced composite (FFRC). The distinctive feature of the construction of the FFRC is that the uniformly spaced straight or wavy CNTs are radially grown on the circumferential surfaces of carbon fibers. The constraining layer of the ACLD treatment is considered to be made of vertically or obliquely reinforced 1–3 piezoelectric composite material. A three-dimensional finite element model has been developed to study the damping characteristics of the laminated FFRC shells integrated with the patches of ACLD treatment. Our results reveal that (i) the planar orientation of CNT waviness has a significant influence on the damping characteristics of the laminated FFRC shells, (ii) damping characteristics of the symmetric cross-ply, and antisymmetric angle-ply laminated FFRC shells are improved if CNT waviness is coplanar with the longitudinal plane of the carbon fiber, and (iii) for the antisymmetric cross-ply laminated FFRC shells, the performance of the ACLD patches becomes maximum for attenuating the fundamental mode when CNT waviness is coplanar with the transverse plane of the carbon fiber.

Effective Thermal Conductivities of a Novel Fuzzy Fiber-Reinforced Composite Containing Wavy Carbon Nanotubes

This article deals with the investigation of the effect of carbon nanotube (CNT) waviness on the effective thermal conductivities of a novel fuzzy fiber-reinforced composite (FFRC). The distinctive feature of the construction of this novel FFRC is that wavy CNTs are radially grown on the circumferential surfaces of the carbon fibers. Effective thermal conductivities of the FFRC are determined by developing the method of cells (MOCs) approach in conjunction with the effective medium (EM) approach. The effect of CNT waviness is studied when wavy CNTs are coplanar with either of the two mutually orthogonal planes of the carbon fiber. The present study reveals that (i) if CNT waviness is parallel to the carbon fiber axis then the axial (K1) and the transverse (K2) thermal conductivities of the FFRC are improved by 86% and 640%, respectively, over those of the base composite when the CNT volume faction present in the FFRC is 16.5% and the temperature is 400 K, (ii) the effective value of K1 of the FFRC containing wavy CNTs being coplanar with the carbon fiber axis is enhanced by 75% over that of containing straight CNTs for the fixed CNT volume faction when the temperature is 400 K, and (iii) the CNT/polymer matrix interfacial thermal resistance does not affect the effective thermal conductivities of the FFRC. The present work also reveals that for a particular value of the CNT volume fraction, optimum values of the CNT waviness parameters, such as the amplitude and the wave frequency of the CNT for improving the effective thermal conductivities of the FFRC can be estimated.

Smart damping of fuzzy fiber reinforced composite plates using 1--3 piezoelectric composites

This article is concerned with the investigation of active constrained layer damping (ACLD) of smart laminated fuzzy fiber reinforced composite (FFRC) plates. The distinctive feature of the construction of this novel FFRC is that the uniformly spaced short carbon nanotubes (CNTs) are radially grown on the circumferential surfaces of carbon fibers. The effect of CNT waviness on the damping characteristics of the laminated FFRC plates is investigated when wavy CNTs are coplanar with either of the two mutually orthogonal planes. The constraining layer of the ACLD treatment is made of vertically/obliquely reinforced 1–3 piezoelectric composite material. A finite element model is developed for the laminated FFRC plates integrated with the patches of ACLD treatment. The effects of different boundary conditions of the FFRC plates and orientation angle of piezoelectric fibers on the damping characteristics of the laminated FFRC plates have also been investigated. Results reveal that if the plane of radially grown wavy CNTs on the circumferential surface of carbon fiber is coplanar with the plane of carbon fiber axis then the attenuation of amplitude of vibrations and the natural frequencies of the laminated FFRC plates are significantly improved over those of the FFRC containing straight CNTs or wavy CNTs being coplanar with the transverse plane of carbon fiber.

Shear lag analysis of a novel short fuzzy fiber-reinforced composite

A novel short fuzzy fiber-reinforced composite (SFFRC) in which the aligned short carbon fiber reinforcements are coated with radially aligned carbon nanotubes (CNTs) is considered in this study. A three-phase shear lag model considering radial and axial deformations of the different constituent phases of the SFFRC has been developed to analyze the stress transfer mechanisms of the SFFRC. Traditionally, the shear lag models have been developed with an application of the axial load only on the representative volume element (RVE) of the composite in an attempt for analyzing the stress transfer between the fiber and the matrix. The three-phase shear lag model derived in this study analyzes the stress transfer to the short carbon fiber considering the application of the axial as well as the radial loads on the RVE of the SFFRC. It is found that if the carbon fiber is coated with radially aligned CNTs, then the axial load transferred to the fiber is significantly reduced due to the radial stiffening of the polymer matrix by CNTs. When compared with the results without CNTs, it is found that almost ~20 and ~29 % reductions in the maximum axial stress in the carbon fiber and the interfacial shear stress along its length occur, respectively, if the value of the applied radial load is twice of the applied axial load and the value of the CNT volume fraction is 0.0236 in the SFFRC. Effects of the variation of the carbon fiber aspect ratio, the carbon fiber volume fraction, and the application of the radial load on the load transfer characteristics of the SFFRC are also investigated.

Effect of carbon nanotube waviness on the effective thermoelastic properties of a novel continuous fuzzy fiber reinforced composite

This paper deals with the investigation of the effect of carbon nanotube (CNT) waviness on the effective coefficient of thermal expansion (CTE) of a novel continuous fuzzy fiber reinforced composite (FFRC). This novel FFRC is composed of carbon fibers, sinusoidally wavy CNTs and epoxy matrix. The sinusoidally wavy CNTs are radially grown on the circumferential surfaces of the carbon fibers. Analytical micromechanics model based on the method of cells (MOC) approach is derived to investigate the influence of the waviness of CNTs on the effective CTEs of the FFRC. The present study reveals that if the amplitudes of the radially grown sinusoidally wavy CNTs are parallel to the axis of the carbon fiber then the thermoelastic properties of the FFRC are significantly improved over those of the FFRC being composed of straight CNTs.

Estimation of thermal conductivities of a novel fuzzy fiber reinforced composite

The effective thermal conductivities of a novel fuzzy fiber reinforced composite (FFRC) have been determined by employing the effective medium approach in conjunction with the composite cylinder assemblage approach. The novel constructional feature of this FFRC is that the uniformly spaced carbon nanotubes (CNTs) are radially grown on the circumferential surfaces of the unidirectional carbon fiber reinforcements. The present study reveals that the transverse thermal conductivities of the FFRC are improved up to ∼1040% and ∼400% over those of the composite without CNTs when the values of CNT volume factions present in the FFRC are 6.88% and 4.27%, respectively. It is also found that the CNT/polymer matrix interfacial thermal resistance does affect the effective thermal conductivities of the FFRC, and the effective values of thermal conductivities of the FFRC are improved with the increase in the values of carbon fiber volume fraction and temperature.

Smart damping of laminated fuzzy fiber reinforced composite shells using 1–3 piezoelectric composites

This paper deals with the investigation of active constrained layer damping (ACLD) of smart laminated continuous fuzzy fiber reinforced composite (FFRC) shells. The distinct constructional feature of a novel FFRC is that the uniformly spaced short carbon nanotubes (CNTs) are radially grown on the circumferential surfaces of the continuous carbon fiber reinforcements. The constraining layer of the ACLD treatment is considered to be made of vertically/obliquely reinforced 1–3 piezoelectric composite materials. A finite element (FE) model is developed for the laminated FFRC shells integrated with the two patches of the ACLD treatment to investigate the damping characteristics of the laminated FFRC shells. The effect of variation of the orientation angle of the piezoelectric fibers on the damping characteristics of the laminated FFRC shells has been studied when the piezoelectric fibers are coplanar with either of the two mutually orthogonal vertical planes of the piezoelectric composite layer. It is revealed that radial growth of CNTs on the circumferential surfaces of the carbon fibers enhances the attenuation of the amplitude of vibrations and the natural frequencies of the laminated FFRC shells over those of laminated base composite shells without CNTs.

Thermoelastic Properties of a Novel Fuzzy Fiber-Reinforced Composite

The effective thermoelastic properties of a fuzzy fiber-reinforced composite (FFRC) have been estimated by employing the generalized method of cells approach and the Mori–Tanaka method. The novel constructional feature of this fuzzy fiber-reinforced composite is that the uniformly aligned carbon nanotubes (CNTs) are radially grown on the circumferential surface of the horizontal carbon fibers. Effective thermoelastic properties of the fuzzy fiber-reinforced composite estimated by the generalized method of cells approach have been compared with those predicted by the Mori–Tanaka method. The present work concludes that the axial thermal expansion coefficient of the fuzzy fiber-reinforced composite slightly increases for the lower values of the carbon fiber volume fraction, whereas the transverse thermal expansion coefficient of the fuzzy fiber-reinforced composite significantly decreases over those of the composite without CNTs. Also, the results demonstrate that the effect of temperature variation on the effective thermal expansion coefficients of the fuzzy fiber-reinforced composite is negligible.

Effect of Carbon Nanotube Waviness on the Elastic Properties of the Fuzzy Fiber Reinforced Composites

A fuzzy fiber reinforced composite (FFRC) reinforced with wavy zig-zag single-walled carbon nanotubes (CNTs) and carbon fibers is analyzed in this study. The distinct constructional feature of this composite is that the wavy CNTs are radially grown on the surface of carbon fibers. To study the effect of the waviness of CNTs on the elastic properties of the FFRC, analytical models based on the mechanics of materials (MOM) approach is derived. Effective elastic properties of the FFRC incorporating the wavy CNTs estimated by the MOM approach have been compared with those predicted by the Mori–Tanaka (MT) method. The values of the effective elastic properties of this composite are estimated in the presence of an interphase between the CNT and the polymer matrix which models the nonbonded van dar Waals interaction between the CNT and the polymer matrix. The effect of waviness of CNTs on the effective properties of the FFRC is investigated when the wavy CNTs are coplanar with two mutually orthogonal planes. The results demonstrate that the axial effective elastic properties of the FFRC containing wavy CNTs can be improved over those of the FFRC with straight CNTs.

Effective properties of a novel composite reinforced with short carbon fibers and radially aligned carbon nanotubes

A novel short fuzzy fiber-reinforced composite reinforced with aligned short carbon fibers and carbon nanotubes (CNTs) has been analyzed in this study. The constructional feature of this composite is that the uniformly aligned CNTs are radially grown on the circumferential surfaces of short carbon fibers. Micromechanical model based on the Mori–Tanaka method is derived to estimate the effective elastic properties of the short fuzzy fiber-reinforced composite. Effective elastic properties of the short fuzzy fiber-reinforced composite estimated by the Mori–Tanaka method have been compared with those predicted by the finite element (FE) method. The effective properties of the short fuzzy fiber-reinforced composite are estimated in the presence and the absence of an interphase between a CNT and the polymer matrix formed due to non-bonded van der Waals interaction between them. It has been found that the transverse effective properties of this composite are significantly improved due to the radial growing of CNTs on the circumferential surface of the short carbon fibers and the CNT/ polymer matrix interphase has negligible effect on the effective properties of the short fuzzy fiber-reinforced composite. Effects of the different types of zig–zag CNTs and the variation of their volume fraction on the effective properties of the short fuzzy fiber-reinforced composite are also investigated.

Effective properties of a novel continuous fuzzy-fiber reinforced composite using the method of cells and the finite element method

Abstract The effective properties of a continuous fuzzy fiber-reinforced composite have been determined by employing the method of cells approach and the finite element (FE) method. The novel constructional feature of this fuzzy fiber-reinforced composite is that the uniformly aligned carbon nanotubes (CNTs) are radially grown on the surface of the horizontal carbon fibers. The effective properties of this fuzzy fiber-reinforced composite are estimated with and without the consideration of an interphase formed due to non-boned interaction between a CNT and the polymer matrix. Effective elastic properties of the fuzzy fiber-reinforced composite estimated by the method of cells approach have been compared with those predicted by the FE method. It has been found that the transverse effective properties of this composite are significantly improved due to the radial growing of CNTs on the surface of the carbon fiber. It is also found that the consideration of the CNT/matrix interphase has a negligible effect on the effective elastic properties of the fuzzy fiber-reinforced composite.

Micromechanical analysis of fuzzy fiber reinforced composites

A novel fuzzy fiber reinforced composite (FFRC) reinforced with zig-zag single-walled carbon nanotubes (CNTs) and carbon fibers is proposed. The distinct constructional feature of this composite is that the uniformly aligned CNTs are radially grown on the surface of carbon fibers. Analytical models based on the mechanics of materials approach and the Mori–Tanaka method are derived to estimate the effective elastic constants of this proposed FFRC. The values of the effective elastic properties of this composite are estimated with and without considering an interphase between the CNT and the polymer matrix. It has been found that the transverse effective properties of this composite are significantly improved due to the radial growing of CNTs on the surface of carbon fiber. The effective properties are also found to be sensitive to the CNT diameter.