scholarly journals Axial shear modulus of a fiber-reinforced composite with random fiber cross-sections

1982 ◽  
Vol 5 (2) ◽  
pp. 393-401
Author(s):  
S. K. Bose ◽  
L. Debnath
Keyword(s):  
Shear Modulus ◽  
Cross Sections ◽  
Graphical Representation ◽  
Coarse Graining ◽  
Fiber Reinforced ◽  
Fiber Reinforced Composite ◽  
Reinforced Composite ◽  
Axial Shear ◽  
The Matrix ◽  
Fiber Reinforced Material

A study is made of the effective axial shear modulus of a fiber reinforced material with random fiber cross-sections so that the micromechanics is governed by stochastic differential equations. A coarse-graining procedure is adopted to investigate the macroscopic behavior of the material. This analysis leads to the formula for the effective axial shear modulusμ∗=μ1/{1−2c(μ2−μ1)/(μ2+μ1)},whereμ1andμ2are the shear modulus of the matrix and fibers respectively andcis the concentration of the fibers less that0.5. Forc>0.5, the fiber and matrix moduli are to be interchanged andcis to be replaced by1−c. The results of this study are compared with those of the theory of fibre reinforced materials. Finally, a numerical example is presented with graphical representation.

A Study of the Fiber-Matrix Interface in Composite Materials

1992 ◽  
Vol 59 (2S) ◽  
pp. S163-S165 ◽  
Author(s):  
Jin O. Kim ◽  
Haim H. Bau
Keyword(s):  
Composite Materials ◽  
Experimental Technique ◽  
Stress Waves ◽  
Matrix Interface ◽  
Fiber Reinforced ◽  
Fiber Reinforced Composite ◽  
Reinforced Composite ◽  
The Matrix ◽  
Fiber Matrix Interface ◽  
Dispersion And Attenuation

A novel experimental technique for studying the characteristics of the interface between the fibers and the matrix in both undamaged and damaged fiber-reinforced composite materials is described. The experimental technique involves the transmission of stress waves in one or more fibers of the composite. The characteristics of the stress waves, such as speed, dispersion, and attenuation, are measured. These measured variables can be correlated with the characteristics of the bonding between the fiber and the matrix.

scholarly journals Carbon Fiber Polymer Composites

2019 ◽  
Vol 1 (1) ◽  
pp. 276-280
Author(s):  
Lenka Markovičová ◽  
Viera Zatkalíková ◽  
Patrícia Hanusová
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Carbon Fiber ◽  
Polymer Composite ◽  
Fiber Orientation ◽  
Environmental Damage ◽  
Fiber Reinforced ◽  
Fiber Reinforced Composite ◽  
Reinforced Composite ◽  
The Matrix

Abstract Carbon fiber reinforced composite materials offer greater rigidity and strength than any other composites, but are much more expensive than e.g. glass fiber reinforced composite materials. Continuous fibers in polyester give the best properties. The fibers carry mechanical loads, the matrix transfers the loads to the fibers, is ductile and tough, protect the fibers from handling and environmental damage. The working temperature and the processing conditions of the composite depend on the matrix material. Polyesters are the most commonly used matrices because they offer good properties at relatively low cost. The strength of the composite increases along with the fiber-matrix ratio and the fiber orientation parallel to the load direction. The longer the fibers, the more effective the load transfer is. Increasing the thickness of the laminate leads to a reduction in the strength of the composite and the modulus of strength, since the likelihood of the presence of defects increases. The aim of this research is to analyze the change in the mechanical properties of the polymer composite. The polymer composite consists of carbon fibers and epoxy resin. The change in compressive strength in the longitudinal and transverse directions of the fiber orientation was evaluated. At the same time, the influence of the wet environment on the change of mechanical properties of the composite was evaluated.

The Effects of Ultrasonic Treatment on Fiber-Reinforced Composite Materials

2009 ◽  
Author(s):  
Chad Braver ◽  
Matthew Tumey ◽  
Adam Harlow ◽  
Qingyou Han
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Ultrasonic Treatment ◽  
Void Content ◽  
Fiber Reinforced ◽  
Fiber Reinforced Composite ◽  
Three Point Bending ◽  
Reinforced Composite ◽  
The Matrix ◽  
Reinforcement Fiber

The mechanical properties of fiber-reinforced composite materials are highly dependent on proper saturation of the resin within the reinforcement fibers. The research evaluates the effect of ultrasonic treatment during composite curing, in an effort to increase interlaminar bonding strength, lower void content, and improve the matrices ability to transfer stresses to the reinforcement fiber. The testing methods that were performed evaluated the effects or the ultrasonic treatment on the specimen in three point bending, and shear between layers of the matrix. The mechanical properties and the microstructure of the test specimen are discussed.

The Influence of a Ductile Interphase on the Overall Elastoplastic Behavior of a Fiber-Reinforced Composite

1999 ◽  
Vol 66 (1) ◽  
pp. 21-31 ◽  
Author(s):  
K. Ding ◽  
G. J. Weng
Keyword(s):  
Biaxial Loading ◽  
Homogenization Theory ◽  
Fiber Reinforced ◽  
Elastoplastic Behavior ◽  
Fiber Reinforced Composite ◽  
Axial Tension ◽  
Reinforced Composite ◽  
Axial Tensile ◽  
The Matrix ◽  
Ductile Interphase

While there exist various homogenization theories for the plasticity of a fiber-reinforced composite, no such theories have been explicitly developed to account for the influence of a ductile interphase. In this paper a simple scheme is developed for such a purpose. The theory evolved out of the work of Qiu and Weng (1992) and Hu (1996), and bears an identical structure to Ponte Castan˜eda’s (1991) variational procedure and Suquet’s (1995, 1996) modified secant moduli approach. An exact solution under the plane-strain biaxial loading is also developed to assess the accuracy of the theory. It is found that, with either a soft or a hard interphase and with or without work-hardening, the homogenization theory can produce sufficiently accurate results under this condition. The theory is then used to examine the influence of the interphase volume concentration on the anisotropic behavior of the composite under axial tension, transverse tension, axial shear, and transverse shear, with both a soft and a hard interphase. The results indicate that, while the axial tensile behavior is not sensitive to the interphase concentration, the behaviors under other types of loading are greatly affected by its presence, especially when the interphase is softer than the matrix.

Computational Multi-Scale Modelling of Fiber-Reinforced Composite Materials

2019 ◽  
Vol 827 ◽  
pp. 263-268
Author(s):  
Tsivolas Eleftherios ◽  
Leonidas N. Gergidis ◽  
Alkiviadis S. Paipetis
Keyword(s):  
Inclusion Problem ◽  
Numerical Homogenization ◽  
Fiber Reinforced ◽  
Fiber Reinforced Composite ◽  
Micro Scale ◽  
Multi Scale ◽  
Reinforced Composite ◽  
The Matrix ◽  
Scale Modelling ◽  
Meso Scale

A cross-ply fiber-reinforced composite in uniaxial tension is modelled using a mesoscale and a micro-scale approach comparing the results from both the analyses. The use of multi-scale modelling gives directly the macroscopic constitutive behaviour of the structures based on its microscopically heterogeneous representative volume element (RVE). In the meso-scale approach the material of each layer is modelled as a homogeneous transversely isotropic material whose properties resulted from a numerical homogenization analysis. One of the main advantages of micro-scale modelling is the ability to simulate damage mechanisms such as matrix cracking, delaminations of the matrix-fiber interface and fibre-damage. In the first part of this study, analytical and numerical homogenization schemes are compared. RVEs of continuous fibre and short-fibre reinforced composites are created, homogenized numerically and compared with the widespread analytical scheme of Mori-Tanaka based on Eshelby’s solution of the single inclusion problem. In the second part, results’ comparison between the simulations of both scales is performed. In the meso-scale model stochasticity has been introduced, assigning interfacial strength following a normal distribution, in order to predict cracking initiation, propagation and saturation at the matrix material. The stresses at the crack tips are compared with the stress fields around the cracks from the micro-scale analysis and the results are in good agreement.

Model and Experimental Analysis of the Fiber-Reinforced Pultrusion Composite Under Tension and Shear

2019 ◽  
Author(s):  
Qian Zhang ◽  
Yanting Zhang ◽  
Wenchun Jiang
Keyword(s):  
Glass Fiber ◽  
Failure Mode ◽  
Strength Increase ◽  
Fiber Reinforced ◽  
Horizontal Shear ◽  
Fiber Reinforced Composite ◽  
Reinforced Composite ◽  
Glass Fiber Reinforced ◽  
The Matrix ◽  
Homogenization Model

Abstract This paper proposed a homogenization model, and compiled a VUMAT subroutine to simulate the tension and shear of fiber-reinforced pultrusion composite (FRPC). Experiments were also performed to verify the accuracy of the homogenization model. The results show that, the simulation results agree well with the experiment data. The stiffness and strength increase with the increase of the diameter of the carbon composite part. The limit shear load and the horizontal shear strength decrease with the increase of the span. When FRPC is under shear with smaller span, the matrix tensile damage initiates first and it is the dominate failure mode, then the matrix and fiber compression damage occur at where the indenters contact. However, with the increase of the span, the delamination damage between the wound glass-fiber reinforced composite and pultrusion glass-fiber reinforced composite occurs and becomes the dominate failure mode for FRPC shear.

Plastic Failure of Fiber-Reinforced Materials

1969 ◽  
Vol 36 (3) ◽  
pp. 542-544 ◽  
Author(s):  
W. Prager
Keyword(s):  
Median Plane ◽  
Fiber Reinforced ◽  
Composite Sheet ◽  
Arbitrary Angle ◽  
Fiber Reinforced Composite ◽  
Reinforced Composite ◽  
Fiber Reinforced Materials ◽  
Simple Tension ◽  
Reinforcing Fibers ◽  
The Matrix

The paper is concerned with failure by plastic flow of the matrix of a fiber-reinforced composite sheet. For unidirectional reinforcement, a completely general state of plane stress in the median plane of the sheet is discussed, but for a two-ply laminate with an arbitrary angle between the two systems of reinforcing fibers only simple tension in any direction to the fibers is investigated.

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