The Fiber Composite With Nonlinear Interface—Part I: Axial Tension

2000 ◽  
Vol 67 (4) ◽  
pp. 727-732 ◽  
Author(s):  
A. J. Levy
Keyword(s):  
Fiber Composite ◽  
Total Potential ◽  
Tension Response ◽  
Axial Tension ◽  
The Matrix ◽  
Nonlinear Interface ◽  
Tension Loading ◽  
Related Paper ◽  
Composite Cylinders ◽  
Poisson Contraction

This paper treats the effective axial tension response of a composite consisting of fibers that debond from the matrix according to nonlinear Needleman-type cohesive zones. A second, related paper (Part II) treats effective antiplane shear response. The composite cylinders representation of a representative volume element (RVE) is employed throughout. For axial tension loading a simple rotationally symmetric boundary value problem for a single composite cylinder is solved. Bounds on the total potential energy and the total complementary energy are shown to coincide and an exact solution for axial extension and Poisson contraction of an RVE of the composite is obtained. Nonlinear interfacial debonding, however, is shown to have a negligible effect on extensional response and only a small, though potentially destabilizing, effect on Poisson contraction response. [S0021-8936(00)02004-3]

The Fiber Composite With Nonlinear Interface—Part II: Antiplane Shear

2000 ◽  
Vol 67 (4) ◽  
pp. 733-739 ◽  
Author(s):  
A. J. Levy
Keyword(s):  
Volume Concentration ◽  
Fiber Composite ◽  
Elastic Field ◽  
Shear Loading ◽  
Antiplane Shear ◽  
Fiber Volume ◽  
Total Potential ◽  
Tension Response ◽  
The Matrix ◽  
Nonlinear Interface

This paper treats the effective antiplane shear response of a composite consisting of fibers that interact with the matrix through nonlinear Needleman-type cohesive zones. The first paper (Part I) examines effective axial tension response. The composite cylinders representation of a representative volume element (RVE) is employed throughout. For antiplane shear loading the elastic field solution for a single composite cylinder is found in the form of a series expansion whose coefficients are governed by an infinite set of nonlinear equations. Bounds on the total potential energy and the total complementary energy of an RVE do not coincide although they are shown to differ by a term of order Oc4 where c is the fiber volume concentration. Interaction effects due to finite volume concentration, coupled with nonlinear interface characterization, are shown to precipitate instability in composite response. [S0021-8936(00)02104-8]

The Viscoelastic Fiber Composite with Nonlinear Interface

2005 ◽  
Vol 73 (2) ◽  
pp. 268-280 ◽  
Author(s):  
Mayue Xie ◽  
Alan J. Levy
Keyword(s):  
Differential Equations ◽  
Fiber Composite ◽  
Elastic Fiber ◽  
Maxwell Model ◽  
Time Dependent ◽  
Shear Mode ◽  
Interface Failure ◽  
Shear Creep ◽  
The Matrix ◽  
Composite Cylinders

Effective viscoelastic response of a unidirectional fiber composite with interfaces that may separate or slip according to uniform Needleman-type cohesive zones is analyzed. Previous work on the solitary elastic composite cylinder problem leads to a formulation for the mean response consisting of a stress-strain relation depending on the interface separation∕slip discontinuity together with an algebraic equation governing its evolution. Results for the fiber composite follow from the composite cylinders representation of a representative volume element (RVE) together with variational bounding. Here, the theory is extended to account for viscoelastic matrix response. For a solitary elastic fiber embedded in a cylindrical matrix which is an nth-order generalized Maxwell model in shear relaxation, a pair of nonlinear nth-order differential equations is obtained which governs the relaxation response through the time dependent stress and interface separation∕slip magnitude. When the matrix is an nth-order generalized Kelvin model in shear creep, a pair of nonlinear nth-order differential equations is obtained governing the creep response through the time dependent strain and interface separation∕slip magnitude. We appeal to the uniqueness of the Laplace transform and its inverse to show that these equations also apply to an RVE with the composite cylinders microstructure. For a matrix, which is a standard linear solid (n=2), the governing equations are analyzed in detail paying particular attention to issues of bifurcation of response. Results are obtained for transverse bulk response and antiplane shear response, while axial tension with related lateral Poisson contraction and transverse shear are discussed briefly. The paper concludes with an application of the theory to the analysis of stress relaxation in the pure torsion of a circular cylinder containing unidirectional fibers aligned parallel to the cylinder axis. For this problem, the redistribution of shear stress and interface slip throughout the cross section, and the movement of singular surfaces, are investigated for an interface model that allows for interface failure in shear mode.

scholarly journals Tensile Characterizations of Oil Palm Empty Fruit Bunch (OPEFB) Fibres Reinforced Composites in Various Epoxy/Fibre Fractions

2021 ◽  
Vol 12 (5) ◽  
pp. 6148-6163
Keyword(s):  
Sodium Hydroxide ◽  
Oil Palm ◽  
Fiber Composite ◽  
Tensile Tests ◽  
Empty Fruit Bunch ◽  
Reinforced Composites ◽  
Soaking Time ◽  
Single Fibers ◽  
The Matrix ◽  
Treated Fiber

Oil palm empty fruit bunch (OPEFB) single fibers and reinforced composites were comprehensively characterized through tensile tests to assess their performance as potential reinforcing materials in polymer composites. The performances of OPEFB single fibers and reinforced composites with untreated and treated fibers conditions were compared. The fibers were variously treated with 3% sodium hydroxide, 2% silane, 3% sodium hydroxide mixed with 2% silane, and 3% sodium hydroxide prior to 2% silane for 2 hours soaking time. The highest toughness of the single fibers test was then selected to proceed with composites fabrication. The OPEFB composites were fabricated in 90:10, 80:20, 70:30, and 60:40 epoxy-fibre fractions. The result shows that the selected treated fiber composite exhibits better performance. The selected treated fiber composite increased the highest ultimate tensile strength by 145.3% for the 90:10 fraction. The highest Young’s Modulus was increased by about 166.7% for 70:30 fraction. Next, the highest toughness was increased by 389.5% for the 30:70 fraction. The treated fibers provided a better interlocking mechanism between the matrix and fibers in reinforced composites, thus improving their interfacial bonding.

Study on Enhancement of Mechanical Strength by Knotted Shape Memory Alloy Fiber in TiNi Fiber Composites

2008 ◽  
Vol 385-387 ◽  
pp. 421-424
Author(s):  
Yong Li Zhao ◽  
Jie Li ◽  
Ming Jin
Keyword(s):  
Shape Memory Alloy ◽  
Mechanical Strength ◽  
Shape Memory ◽  
Fiber Composite ◽  
Stress Transfer ◽  
Fiber Composites ◽  
Tension Test ◽  
Fiber Tension ◽  
The Matrix ◽  
Straight Fiber

In this paper, the experimental investigation into the enhancement of mechanical strength in shape memory alloy (SMA) fiber composites is made by using knotted fiber at the two ends instead of straight fiber. TiNi SMA fiber with both ends knotted is used for purpose of better ensuring stress transfer from the matrix to the fiber than straight fiber. Tension test is carried out above the austenitic finish temperature in air. Specimens are heated by means of electrical resistive lamplight heating. The results indicate that the mechanical strength is larger in the knotted fiber composite than in the straight fiber composite. Knotted fiber exerts the superiority of TiNi SMA fiber composite.

Fatigue Failures of Differences Behaviour on CSM/Woven Roving Composite Materials

2013 ◽  
Vol 471 ◽  
pp. 335-340 ◽  
Author(s):  
A.M.T. Arifin ◽  
S. Abdullah ◽  
Rozli Zulkifli ◽  
D.A. Wahab
Keyword(s):  
Composite Materials ◽  
Epoxy Resin ◽  
Composite Structure ◽  
Loading Condition ◽  
Fatigue Loading ◽  
The Matrix ◽  
Chopped Strand Mat ◽  
Materials Used ◽  
Tension Loading ◽  
Fatigue Failures

This paper presents the investigation of composite materials lamination using different materials in the structure of lamination. The main purpose of the study is to evaluate the behaviour of characteristics in composite materials subjected to difference of fatigue loading, leading to understand the criteria that influence the behaviour of composite lamination structure. Therefore, in this research, the orientation of lamination structure used is 00/900and the material selected for the study were chopped strand mat (csm) and woven roving fabric (wr) as a reinforcement and the matrix used were polyester and epoxy resin. The composite lamination structure was produced using hand lay-up technique. The fatigue condition experiment of composite materials in this research was carried under tension-tension loading. With difference in fatigue loading condition, the lifetime of composite structure will be different and the cracking phenomenon in the structure will also be different. It is suggested that, different number of lamination and amount of reinforcement and matrix, produce a variety of materials characteristic with respect to elasticity of material. An implication of the study in this research showed various behaviour of composite materials with different materials used and it showed a difference phenomenon in comparison to metalic materials.

scholarly journals Temperature dependence of statistical fatigue strengths for unidirectional carbon fiber reinforced plastics under tension loading

2019 ◽  
Vol 54 (14) ◽  
pp. 1797-1806 ◽  
Author(s):  
Masayuki Nakada ◽  
Yasushi Miyano
Keyword(s):  
Fatigue Strength ◽  
Carbon Fiber ◽  
Longitudinal Direction ◽  
Fiber Reinforced ◽  
Carbon Fiber Reinforced Plastics ◽  
Reinforced Plastics ◽  
The Matrix ◽  
Fiber Reinforced Plastics ◽  
Carbon Fiber Reinforced ◽  
Tension Loading

The formulation for time- and temperature-dependent statistical static and fatigue strengths for carbon fiber reinforced plastics laminates is newly proposed based on the physically serious role of resin viscoelasticity as the matrix of carbon fiber reinforced plastics. In this study, this formulation is applied to the tensile strength along the longitudinal direction of unidirectional carbon fiber reinforced plastics constituting the most important data for the reliable design of carbon fiber reinforced plastics structures which are exposed to elevated temperatures for a significant period of their operative life. The statistical distribution of the static and fatigue strengths under tension loading along the longitudinal direction of unidirectional carbon fiber reinforced plastics were measured at various temperatures by using resin-impregnated carbon fiber reinforced plastics strands as specimens. The master curves for the fatigue strength as well as the static strength of carbon fiber reinforced plastics strand were constructed based on the time–temperature superposition principle for the matrix resin viscoelasticity. The long-term fatigue strength of carbon fiber reinforced plastics strand can be predicted by using the master curve of fatigue strength.

Fabrication and Testing of Abaca Fibre Reinforced Epoxy Composites for Automotive Applications

2013 ◽  
Vol 718-720 ◽  
pp. 63-68 ◽  
Author(s):  
Raja R. Niranjan ◽  
S. Junaid Kokan ◽  
R. Sathya Narayanan ◽  
S. Rajesh ◽  
V.M. Manickavasagam ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Natural Fiber ◽  
Fibre Composite ◽  
Fiber Composite ◽  
Salt Water ◽  
Natural Fibers ◽  
Natural Fibre ◽  
Industrial Applications ◽  
Vertical Orientation ◽  
The Matrix

The natural fibre composite materials are nowadays playing a vital role in replacing the conventional and synthetic materials for industrial applications. This paper proposes a natural fiber composite made of Abaca fibre as reinforcing agent with Epoxy resin as the matrix, manufactured using Hand Lay-up method. Glass Fiber Reinforced Plastics (woven rovings) are used to improve the surface finish and impart more strength and stiffness to natural fibers. In this work, the fibers are arranged in alternative layers of abaca in horizontal and vertical orientation. The mechanical properties of the composite are determined by testing the samples for tensile and flexural strength. It is observed that the tensile strength of the composite material is dependent on the strength of the natural fiber and also on the interfacial adhesion between the reinforcement and the matrix. The composite is developed for automobile dashboard/mudguard application. It may also be extended to biomedical, electronics and sports goods manufacturing. It can also be used in marine products due to excellent resistance of abaca to salt water damage since the tensile strength when it is wet.

Determination of Flexible Interlayer Thickness for Fiber Reinforced Composites

1989 ◽  
Vol 170 ◽  
Author(s):  
King H. Lo ◽  
Robert W. Schmitz ◽  
William G. Gottenberg
Keyword(s):  
Fiber Composites ◽  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Stress Distributions ◽  
Interlayer Thickness ◽  
Fiber Reinforced ◽  
The Matrix ◽  
Composite Cylinders ◽  
Selection Of

AbstractThe influence of flexible interlayers/interphases on the performance of unidirectional fiber reinforced composites is studied. Micromechanical analysis based on the embedded composite cylinders model is used to study the stiffness as well as the internal stress distributions within the matrix phase of composites. Based on the results of the analysis, a criterion is proposed for the selection of optimal interlayer thickness for fiber composites. The proposed criterion gives results which seem to correlate well with the experimental data published in the literature.

The M-Integral Analysis for a Nano-Inclusion in Plane Elastic Materials Under Uni-Axial or Bi-Axial Loadings

2009 ◽  
Vol 77 (2) ◽  
Author(s):  
Tong Hui ◽  
Yi-Heng Chen
Keyword(s):  
Surface Effect ◽  
Continuum Theory ◽  
Elastic Materials ◽  
Hard Inclusion ◽  
Surface Parameters ◽  
Integral Analysis ◽  
Axial Tension ◽  
Soft Inclusion ◽  
Tension Loading ◽  
M Integral

This paper deals with the M-integral analysis for a nano-inclusion in plane elastic materials under uni-axial or bi-axial loadings. Based on previous works (Gurtin and Murdoch, 1975, “A Continuum Theory of Elastic Material Surfaces,” Arch. Ration. Mech. Anal., 57, pp. 291–323; Mogilevskaya, et al., 2008, “Multiple Interacting Circular Nano-Inhomogeneities With Surface/Interface Effects,” J. Mech. Phys. Solids, 56, pp. 2298–2327), the surface effect induced from the surface tension and the surface Lamé constants is taken into account, and an analytical solution is obtained. Four kinds of inclusions including soft inclusion, hard inclusion, void, and rigid inclusions are considered. The variable tendencies of the M-integral for each of four nano-inclusions against the loading or against the inclusion radius are plotted and discussed in detail. It is found that in nanoscale the surface parameters for the hard inclusion or rigid inclusion have a little or little influence on the M-integral, and the values of the M-integral are always negative as they would be in macroscale, whereas the surface parameters for the soft inclusion or void yield significant influence on the M-integral and the values of the M-integral could be either positive or negative depending on the loading levels and the surface parameters. Of great interest is that there is a neutral loading point for the soft inclusion or void, at which the M-integral transforms from a negative value to a positive value, and that the bi-axial loading yields similar variable tendencies of the M-integral as those under the uni-axial tension loading. Moreover, the bi-axial tension loading increases the neutral loading point, whereas the bi-axial tension-compression loading decreases it. Particularly, the magnitude of the negative M-integral representing the energy absorbing of the soft inclusion or void increases very sharply as the radius of the soft inclusion or void decreases from 5 nm to 1 nm.

An Improved Shear-Lag Model for a Single Fiber Composite with a Ductile Matrix

2007 ◽  
Vol 334-335 ◽  
pp. 333-336
Author(s):  
Souta Kimura ◽  
Jun Koyanagi ◽  
Takayuki Hama ◽  
Hiroyuki Kawada
Keyword(s):  
Fiber Composite ◽  
Matrix Material ◽  
Single Fiber ◽  
Uniaxial Tensile ◽  
Fiber Direction ◽  
Stress Distributions ◽  
Shear Lag ◽  
Shear Lag Model ◽  
The Matrix ◽  
Lag Model

A shear-lag model is developed to predict the stress distributions in and around an isolated fiber in a single-fiber polymer matrix composite (PMC) subjected to uniaxial tensile loading and unloading along the fiber direction. The matrix is assumed to be an elasto-plastic material that deforms according to J2 flow theory. The stress distributions are obtained numerically and compared with a different shear-lag model that employs total strain theory as a constitutive equation of the matrix material. An effect of the difference between the models on the derived stress state is discussed.

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