Environmental Effects on Interface Behavior in Graphite / Epoxy Single Fiber Composites

1995 ◽  
Vol 385 ◽  
Author(s):  
Linda S. Schadler ◽  
Michael J. Koczak ◽  
Maher S. Amer
Keyword(s):  
Degradation Mechanism ◽  
Interfacial Shear Stress ◽  
Fiber Composites ◽  
Interfacial Shear ◽  
Single Fiber ◽  
Graphite Fiber ◽  
Matrix Interface ◽  
Micro Raman Spectroscopy ◽  
Stress Profiles ◽  
Fiber Matrix Interface

ABSTRACTToray M40 graphite fiber / Epon 828 epoxy resin single fiber composites with both sized and unsized fibers were exposed to distilled water at 50°C and 100°C, 10% NaOH and HCl aqueous solutions at 50°C, and air at 100°C. Micro Raman spectroscopy was used to measure the strain and interfacial shear stress profiles as a function of environmental exposure. It was found that the degradation mechanism is primarily a mechanical failure of the fiber/matrix interface.

scholarly journals Multiscale Modeling of Fiber Fragmentation Process in Aligned ZnO Nanowires Enhanced Single Fiber Composites

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Parisa Marashizadeh ◽  
Mohammad Abshirini ◽  
Jingyu Wang ◽  
Mrinal C. Saha ◽  
Yingtao Liu
Keyword(s):  
Shear Strength ◽  
Multiscale Modeling ◽  
Interfacial Shear Strength ◽  
Fiber Composites ◽  
Interfacial Shear ◽  
Zno Nanowires ◽  
Single Fiber ◽  
Computational Domain ◽  
The Matrix ◽  
Fiber Fragmentation

AbstractA three-dimensional multiscale modeling framework is developed to analyze the failure procedure of radially aligned zinc oxide (ZnO) enhanced single fiber composites (SFC) under tensile loading to understand the interfacial improvement between the fiber and the matrix. The model introduces four levels in the computational domain. The nanoscale analysis calculates the size-dependent material properties of ZnO nanowires. The interaction between ZnO nanowires and the matrix is simulated using a properly designed representative volume element at the microscale. At the mesoscale, the interface between the carbon fiber and the surrounding area is modeled using the cohesive zone approach. A combination of ABAQUS Finite element software and the failure criteria modeled in UMAT user subroutine is implemented to simulate the single fiber fragmentation test (SFFT) at the macroscale. The numerical results indicate that the interfacial shear strength of SFC can be improved up to 99% after growing ZnO nanowires on the fiber. The effect of ZnO nanowires geometries on the interfacial shear strength of the enhanced SFC is also investigated. Experimental ZnO nanowires enhanced SFFTs are performed on the fabricated samples to validate the results of the developed multiscale model. A good agreement between the numerical and the experimental results was observed.

Fiber/matrix interface stress analysis of flax-fiber composites under transverse loading considering material nonlinearity

2020 ◽  
Vol 39 (9-10) ◽  
pp. 345-360
Author(s):  
Baris Sabuncuoglu ◽  
Onur Cakmakci ◽  
Fevzi S Kadioglu
Keyword(s):  
Fiber Composites ◽  
Flax Fiber ◽  
Material Nonlinearity ◽  
Transverse Strain ◽  
Matrix Interface ◽  
Transverse Loading ◽  
Stress Concentrations ◽  
Transverse Cracks ◽  
Fiber Matrix Interface ◽  
Fiber Matrix

Distribution of stresses in fiber/matrix interface in UD flax fiber reinforced composites is investigated under transverse loading and compared with conventional synthetic fibers. Micro-scale finite element models with representative volume elements are generated with various fiber packing types and fiber volume ratios. The study is performed for various strain values, which take into account the material nonlinearity of matrix. The results show that significantly lower stress concentrations exist in the case of flax fibers compared to glass fiber composites, explaining the absence of transverse cracks until failure in previously conducted transverse tension tests. Increase in the applied transverse strain causes a further decrease in the stress concentrations due to the nonlinear behavior of the matrix.

Mechanical Property Study of the Fiber-Matrix Interface in SiC/SiC Composites

2006 ◽  
Author(s):  
Eric L. Jones ◽  
Sergey Yarmolenko ◽  
Devdas Pai ◽  
Jag Sankar
Keyword(s):  
Shear Strength ◽  
Interfacial Shear Strength ◽  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Interfacial Shear ◽  
Fatigue Properties ◽  
Matrix Interface ◽  
Fiber Matrix Interface ◽  
Fiber Matrix ◽  
Sic Composites

The fiber-matrix interface between ceramic fibers and ceramic matrix plays a major role in the fatigue properties and toughness of continuous fiber reinforced ceramic matrix composites (CMCs). Boron Nitride (BN) is a widely used fiber coating material that provides a weak bond between the fiber and matrix. A weak fiber-matrix interface increases the strength and toughness of the overall CMC. Single fiber push-out tests were performed to study interfacial shear strength as a main parameter defining fatigue properties and toughness of SiC/SiC composites. The fiber-matrix interfacial shear strength was studied in melt infiltrated Hi-Nicalon/BN(CVI)/SiC composites exposed to various temperature and loading conditions, similar to those that are used in actual applications. Hi-Nicalon fibers with diameters of 13-14.5 μm were pushed out from samples with thicknesses ranging from 125-280 μm using a spherical tip with a 1 μm radius and 90° conical shape. Interfacial shear strength was calculated from sliding load, fiber diameter and sample thickness. Due to significant scattering, 30 individual push tests in every sample were used to obtain the average interfacial shear strength. The virgin sample has a shear strength of 20 MPa which is higher than tensile tested samples (12 MPa). Annealing of a virgin specimen for 100 hours at 1000°C slightly increased shear strength up to 21.5 MPa while annealing at 1100°C and 1200°C led to significant increase of shear strength up to 29 and 39 MPa correspondingly. This effect is associated with BN degradation at temperatures >1000°C.

Effects of Thermal Cycling on Properties of Carbon Fiber/Aluminum Composites

1988 ◽  
Vol 110 (2) ◽  
pp. 89-95 ◽  
Author(s):  
Tetsuyuki Kyono ◽  
Etsuro Kuroda ◽  
Atsushi Kitamura ◽  
Tsutomu Mori ◽  
Minoru Taya
Keyword(s):  
Mechanical Properties ◽  
Carbon Fiber ◽  
Thermal Cycling ◽  
Degradation Mechanism ◽  
Matrix Interface ◽  
Aluminum Composites ◽  
Longitudinal Tensile Strength ◽  
Casting Technique ◽  
Fiber Matrix Interface ◽  
Fiber Matrix

Effects of thermal cycling on mechanical properties such as longitudinal tensile strength, interlaminar shear strength and work of fracture of carbon fiber/aluminum composites have been investigated. The composite specimens fabricated by a squeeze casting technique were thermally cycled in fluidized baths between room temperature and various temperatures (250, 300, and 350° C) for up to 1000 cycles. The cross sections and fracture surfaces were examined to clarify the degradation mechanism. Significant degradation of the mechanical properties by thermal cycling was observed in untreated carbon fiber/aluminum composites whereas much less degradation in surface treated carbon fiber/aluminum composites. Microscopic observations and short beam shear tests have indicated that the degradation of mechanical properties is caused by debonding at the fiber/matrix interface. The fiber/matrix interface for surface treated fiber was more resistant to debonding. It is concluded that thermal cycling damage of carbon fiber/aluminum composites can be minimized by increasing their fiber/matrix bond strengths.

scholarly journals The fiber‐matrix interface in Ioncell cellulose fiber composites and its implications for the mechanical performance

2020 ◽  
pp. 50306
Author(s):  
Mindaugas Bulota ◽  
Simona Sriubaite ◽  
Anne Michud ◽  
Kaarlo Nieminen ◽  
Mark Hughes ◽  
...  
Keyword(s):  
Mechanical Performance ◽  
Cellulose Fiber ◽  
Fiber Composites ◽  
Matrix Interface ◽  
Fiber Matrix Interface ◽  
Fiber Matrix

Analysis of a Crack Bridged by a Single Fiber

1992 ◽  
Vol 59 (3) ◽  
pp. 524-529 ◽  
Author(s):  
G. Meda ◽  
P. S. Steif
Keyword(s):  
Approximate Method ◽  
Singular Integral Equations ◽  
Single Fiber ◽  
Solution Technique ◽  
Matrix Interface ◽  
Matrix Cracks ◽  
Fiber Matrix Interface ◽  
Edge Dislocations ◽  
Crack Faces ◽  
Frictional Slip

With the goal of assessing the accuracy of a widely used approximate method of analyzing bridged matrix cracks, an idealized problem representing a crack bridged by a single fiber is studied in detail. Our solution technique, which accounts for frictional slip at the fiber-matrix interface explicitly, involves the use of distributions of edge dislocations to represent the opening of the crack faces and the slip at the interface. Through this method, the solution is reduced to a set of three coupled singular integral equations which are solved numerically. The results are compared with those from the approximate method, and some sources of discrepancy between the two results are explored.

scholarly journals Surface roughness characterization of various ceramic fibers using AFM and low-voltage SEM

1994 ◽  
Vol 52 ◽  
pp. 1066-1067
Author(s):  
K. L. More ◽  
E. Lara-Curzio ◽  
R. A. Lowden
Keyword(s):  
Surface Roughness ◽  
Low Voltage ◽  
Interfacial Shear Stress ◽  
Fiber Surface ◽  
Interfacial Properties ◽  
Matrix Interface ◽  
Ceramic Fibers ◽  
Pull Out ◽  
Fiber Matrix Interface ◽  
Fiber Matrix

The effect of interfacial properties in fiber-reinforced ceramic matrix composites is critical to the overall mechanical behavior of the composite material. The creation of a relatively weak fiber/matrix interface allows for the beneficial actions of debonding and fiber pull-out to occur, thus improving the fracture toughness and, in many cases, the ultimate strength of the composite. To date, the best room temperature interfacial properties have been achieved by coating the fibers with either carbon or boron nitride. There are several factors which contribute to the interfacial properties of a composite, including the residual stress (clamping stress) present at the fiber/matrix interface, which is a result of differences in thermal expansion, and the fiber surface roughness. In this study, the surfaces of several ceramic fibers have been characterized qualitatively using a Hitachi S-4500 FEG SEM operated at low voltages and quantitatively using a Topometrix atomic force microscope (AFM). This study is part of an overall program relating fiber surface roughness to the interfacial shear stress.

E-Glass/DGEBA/m-PDA single fiber composites: The effect of strain rate on interfacial shear strength measurements

2000 ◽  
Vol 21 (3) ◽  
pp. 450-465 ◽  
Author(s):  
G. A. Holmes ◽  
R. C. Peterson ◽  
D. L. Hunston ◽  
W. G. McDonough
Keyword(s):  
Shear Strength ◽  
Strain Rate ◽  
Interfacial Shear Strength ◽  
Fiber Composites ◽  
Interfacial Shear ◽  
Single Fiber
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