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 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]

Effect of Interphases on Micro and Macromechanical Behavior of Hexagonal-Array Fiber Composites

1990 ◽  
Vol 57 (4) ◽  
pp. 956-963 ◽  
Author(s):  
J. D. Achenbach ◽  
H. Zhu
Keyword(s):  
Fiber Composite ◽  
Volume Ratio ◽  
Fiber Composites ◽  
Effective Moduli ◽  
Hexagonal Array ◽  
Fiber Volume ◽  
Unidirectional Fiber Composite ◽  
Circumferential Tensile Stress ◽  
The Matrix ◽  
Stress And Deformation

The effect of interphase stiffness on microstresses and macromechanical behavior has been investigated for transverse loading of an hexagonal-array unidirectional fiber composite. The interphase is modeled by a layer which resists radial extension and circumferential shear deformation. Taking advantage of the periodicity of the medium, the states of stress, and deformation in a basic cell have been analyzed numerically by the use of the boundary element method. The circumferential tensile stress along the matrix side of the interphase and the radial stress in the interphase have been analyzed for various values of the interphase parameters and the fiber volume ratio. The micromechanical results have also been used to determine the effect of interphase stiffness on the effective moduli. The calculated values have been compared with analytical results that were adjusted for interphase stiffness.

Determination of fiber volume fraction in a cured laminate

2021 ◽  
pp. 002199832110112
Author(s):  
Qing Yang Steve Wu ◽  
Nan Zhang ◽  
Weng Heng Liew ◽  
Vincent Lim ◽  
Xiping Ni ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Fiber Volume Fraction ◽  
Evaluation Method ◽  
Volume Fraction ◽  
Matrix Material ◽  
Volume Ratio ◽  
Gravimetric Analysis ◽  
Fiber Volume ◽  
Laser Ultrasonic ◽  
The Matrix

Propagation of ultrasonic wave in Carbon Fiber Reinforced Polymer (CFRP) is greatly influenced by the material’s matrix, resins and fiber volume ratio. Laser ultrasonic broadband spectral technique has been demonstrated for porosity and fiber volume ratio extraction on unidirection aligned CFRP laminates. Porosity in the matrix materials can be calculated by longitudinal wave attenuation and accurate fiber volume ratio can be derived by combined velocity through the high strength carbon fiber and the matrix material with further consideration of porosity effects. The results have been benchmarked by pulse-echo ultrasonic tests, gas pycnometer and thermal gravimetric analysis (TGA). The potentials and advantages of the laser ultrasonic technique as a non-destructive evaluation method for CFRP carbon fiber volume fraction evaluation were demonstrated.

Design and Optimization of Biopolyester Bagasse Fiber Composites

2007 ◽  
Vol 1 (1) ◽  
pp. 46-55 ◽  
Author(s):  
Alma Hodzic ◽  
Richard Coakley ◽  
Ray Curro ◽  
Christopher C. Berndt ◽  
Robert A. Shanks
Keyword(s):  
Stress Transfer ◽  
Soxhlet Extraction ◽  
Interfacial Stress ◽  
Fiber Volume ◽  
Mechanical Reinforcement ◽  
Xylem Structure ◽  
Design And Optimization ◽  
The Matrix ◽  
Packaging Industry ◽  
Bagasse Fiber

Bagasse fiber, a by-product of the sugar making process, maintains a coherent xylem structure and can offer mechanical reinforcement to composite materials. Biopolyester bagasse composites were prepared with biodegradable matrices polyhydroxylbutyrate (PHB) and its copolymer containing polyhydroxyvalerate (PHBV). Both biopolymers were reinforced with treated and untreated bagasse fibers, as well as fiber volume fractions involving two fiber lengths. Optimized properties were achieved with PHB-bagasse composite surpassing the PHB flexural strength by 50% and achieving higher strength and modulus than the standard thermoplastics. The bagasse fibers were cleaned with boiling water and acetone soxhlet extraction to avoid using adhesive chemicals and, therefore, comply with biosafety standards in the packaging industry. A significant improvement in the interfacial stress transfer between the fiber and the matrix was achieved with the fibers subjected to both washing and acetone treatment. While the crystallization of PHBV was shown to be controllable by processing conditions, it was concluded that no transcrystalline region was formed with this particular resin in any of the composites. Bagasse was shown to be an effective filler for PHBV; although the results varied somewhat due to the surface treatment of the bagasse fibers. On average, long fiber bagasse composites displayed flexural moduli 33% higher than those of PHBV. Overall, the results demonstrated the positive potential of bagasse to reinforce both biopolyester matrices.

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.

The Elastic Field of an Elliptic Inclusion With a Slipping Interface

1986 ◽  
Vol 53 (1) ◽  
pp. 103-107 ◽  
Author(s):  
E. Tsuchida ◽  
T. Mura ◽  
J. Dundurs
Keyword(s):  
Closed Form ◽  
Infinite Series ◽  
Elastic Field ◽  
Elliptic Inclusion ◽  
Numerical Examples ◽  
Elastic Fields ◽  
Bonded Interface ◽  
The Matrix ◽  
Displacement Potentials ◽  
Uniform Expansion

The paper analyzes the elastic fields caused by an elliptic inclusion which undergoes a uniform expansion. The interface between the inclusion and the matrix cannot sustain shear tractions and is free to slip. Papkovich–Neuber displacement potentials are used to solve the problem. In contrast to the perfectly bonded interface, the solution cannot be expressed in closed form and involves infinite series. The results are illustrated by numerical examples.

Toughness of ECC Evaluated by Nominal Fracture Energy

2012 ◽  
Vol 238 ◽  
pp. 57-60 ◽  
Author(s):  
Shu Ling Gao ◽  
Wei Shao ◽  
Jin Li Qiao ◽  
Ling Wang
Keyword(s):  
Glass Fiber ◽  
Fracture Energy ◽  
Steel Fiber ◽  
Volume Ratio ◽  
Fiber Glass ◽  
Fiber Volume ◽  
High Durability ◽  
The Matrix ◽  
Pva Fiber ◽  
Very High

ECC (Engineered Cementitious Composites) has ultra-high toughness and can be used in the zone needing the ultra-high tensile strain and very high durability. In order to investigate the toughness of ECC, the normal fracture energy GFis calculated and compared with ordinary concrete. The influence of the matrix (fly ash, silicon fume), the fiber (glass fiber, steel fiber and PVA fiber) and the fiber volume ratio on the GFof ECC are analyzed. The research indicates that silicon fume and glass fiber, steel fiber are all not able to be used in ECC. But flash ash and PVA fiber are very suit for using in ECC, the toughness of ECC increases with the increase of their content.

Development of Generalized Plane-Strain Tensors for the Concentric Cylinder

1995 ◽  
Vol 62 (3) ◽  
pp. 590-594
Author(s):  
N. Chandra ◽  
Zhiyum Xie
Keyword(s):  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Transformation Strain ◽  
Inclusion Problem ◽  
Infinite Domain ◽  
Concentric Cylinder ◽  
Finite Radius ◽  
Fiber Volume ◽  
Thermal Residual Stresses ◽  
The Matrix

A pair of two new tensors called GPS tensors S and D is proposed for the concentric cylindrical inclusion problem. GPS tensor S relates the strain in the inclusion constrained by the matrix of finite radius to the uniform transformation strain (eigenstrain), whereas tensor D relates the strain in the matrix to the same eigenstrain. When the cylindrical matrix is of infinite radius, tensor S reduces to the appropriate Eshelby’s tensor. Explicit expressions to evaluate thermal residual stresses σr, σθ and σz in the matrix and the fiber using tensor D and tensor S, respectively, are developed. Since the geometry of the present problem is of finite radius, the effect of fiber volume fraction on the stress distribution can be easily studied. Results for the thermal residual stress distributions are compared with Eshelby’s infinite domain solution and finite element results for a specified fiber volume fraction.

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