Interface Properties for Ceramic Composites from a Single-Fiber Pull-Out Test

1989 ◽  
Vol 170 ◽  
Author(s):  
Elizabeth P. Butler ◽  
Edwin R. Fuller ◽  
Helen M. Chan
Keyword(s):  
Friction Coefficient ◽  
Shear Resistance ◽  
Ceramic Composites ◽  
Single Fiber ◽  
Displacement Curve ◽  
Interface Properties ◽  
Model Composite ◽  
Pull Out ◽  
Fiber Matrix ◽  
Clamping Pressure

AbstractAn experimental approach has been developed using a single-fiber pullout test to measure intrinsic interface properties for ceramic composites. The properties are determined from a pull-out, force-displacement curve, which is directly related to reinforcement toughening via fiber/matrix debonding and frictional pull-out. They were evaluated for a model composite system of continuous SiC fibers with various surface treatments in a borosilicate glass matrix. For the processing conditions used, the interface fracture toughness and the interface frictional shear resistance were found to be 1.0 ± 0.5 J/m2 and 3.3 ± 0.6 MPa, respectively, for as-received fibers. Experiments conducted with long embedded fiber lengths allowed the shear resistance to be deconvolved into an interface friction coefficient of 0.05 ± 0.01 and an initial fiber-clamping pressure of 65 ± 6 MPa. Nitric acidwashed fibers gave an increased interface toughness of 3.6 ± 0.1 J/m2 and friction coefficient of 0.08 ± 0.02, but nearly the same initial clamping pressure, 72 ± 12 MPa. Calculations of the clamping pressure from the fiber/matrix thermal expansion mismatch and from stress birefringence measurements in the glass were in general agreement with this value.

scholarly journals Numerical simulation of fiber-matrix debonding in single fiber pull-out tests

2020 ◽  
Vol 2 (1) ◽  
pp. 21-35
Author(s):  
Lukas Hoppe
Keyword(s):  
Crack Initiation ◽  
Cohesive Zone ◽  
Single Fiber ◽  
Displacement Curve ◽  
Fe Model ◽  
Pull Out ◽  
Peridynamic Model ◽  
Reference Experiment ◽  
Fiber Matrix ◽  
Force Displacement

The present work deals with the numerical crack simulation of fiber-matrix debonding in single fiber pull-out tests. For this purpose, two models are used: a finite element model (FE model) with the cohesive zone approach and a peridynamic model. For calibration a reference experiment is applied. In addition analytical equations are used for reference values. The influence of the model parameters and the material parameters of the cohesive zone model on the force-displacement curve is investigated. Besides the free fiber length, the critical interface strength, the critical energy release rate as well as the initial interface stiffness have a great influence on the force-displacement curve of the pull-out test. From the crack simulation it can be seen that Mode I has an influence on the crack initiation, but further crack growth after initiation is dominated by Mode II. The FE model can be calibrated in a way that the crack initiation point and the maximum force correspond to the reference experiment. The peridynamic model depicts a comparable crack formation process.

scholarly journals Dynamic Single-Fiber Pull-Out of Polypropylene Fibers Produced with Different Mechanical and Surface Properties for Concrete Reinforcement

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 722
Author(s):  
Enrico Wölfel ◽  
Harald Brünig ◽  
Iurie Curosu ◽  
Viktor Mechtcherine ◽  
Christina Scheffler
Keyword(s):  
Tensile Strength ◽  
Dynamic Loading ◽  
Melt Spinning ◽  
Structural Changes ◽  
High Surface ◽  
Single Fiber ◽  
Scanning Calorimetry ◽  
Matrix Interaction ◽  
Pull Out ◽  
Fiber Matrix

In strain-hardening cement-based composites (SHCC), polypropylene (PP) fibers are often used to provide ductility through micro crack-bridging, in particular when subjected to high loading rates. For the purposeful material design of SHCC, fundamental research is required to understand the failure mechanisms depending on the mechanical properties of the fibers and the fiber–matrix interaction. Hence, PP fibers with diameters between 10 and 30 µm, differing tensile strength levels and Young’s moduli, but also circular and trilobal cross-sections were produced using melt-spinning equipment. The structural changes induced by the drawing parameters during the spinning process and surface modification by sizing were assessed in single-fiber tensile experiments and differential scanning calorimetry (DSC) of the fiber material. Scanning electron microscopy (SEM), atomic force microscopy (AFM) and contact angle measurements were applied to determine the topographical and wetting properties of the fiber surface. The fiber–matrix interaction under quasi-static and dynamic loading was studied in single-fiber pull-out experiments (SFPO). The main findings of microscale characterization showed that increased fiber tensile strength in combination with enhanced mechanical interlocking caused by high surface roughness led to improved energy absorption under dynamic loading. Further enhancement could be observed in the change from a circular to a trilobal fiber cross-section.

Electromechanical study of carbon fiber composites

1998 ◽  
Vol 13 (11) ◽  
pp. 3081-3092 ◽  
Author(s):  
Xiaojun Wang ◽  
Xuli Fu ◽  
D. D. L. Chung
Keyword(s):  
Carbon Fiber ◽  
Electrical Resistance ◽  
Fiber Composites ◽  
Single Fiber ◽  
Fiber Direction ◽  
Carbon Fiber Composites ◽  
Fiber Waviness ◽  
Pull Out ◽  
The Matrix ◽  
Fiber Matrix

Electromechanical testing involving simultaneous electrical and mechanical measurements under load was used to study the fiber-matrix interface, the fiber residual compressive stress, and the degree of marcelling (fiber waviness) in carbon fiber composites. The interface study involved single fiber pull-out testing while the fiber-matrix contact electrical resistivity was measured. The residual stress study involved measuring the electrical resistance of a single fiber embedded in the matrix while the fiber was subjected to tension through its exposed ends. The marcelling study involved measuring the electrical resistance of a composite in the through-thickness direction while tension within the elastic regime was applied in the fiber direction.

The Use of a Single-Fiber Fragmentation Test to Study Environmental Durability of Interfaces/Interphases Between Epoxy and a Glass Fiber

1993 ◽  
Vol 304 ◽  
Author(s):  
Carol L. Schuute ◽  
Walter McDonough ◽  
Masatoshi Shioya ◽  
Donald L. Hunston
Keyword(s):  
Glass Fiber ◽  
Fiber Surface ◽  
Critical Length ◽  
Single Fiber ◽  
Resin Matrix ◽  
Matrix Interface ◽  
Model Composite ◽  
Fragmentation Test ◽  
Fiber Matrix ◽  
Fiber Fragmentation

AbstractThis work examines the usefulness of the single-fiber fragmentation test in studying the durability of fiber/matrix interfaces/interphases. This test measures the critical length/diameter ratio (L/D) of the fiber fragments formed in the test and relates this length to the interface's strength, or ability to transfer load. In the work reported here, we immersed samples of epoxy containing a single-glass fiber - that was previously sized with an epoxy-compatible coating - in either 65 or 75 °C water and tested after different times of exposure. In general, this ratio increased as a function of time of exposure to water. During exposure at 75 °C, the fibers' L/D in the samples did not increase significantly until after the sample reached its “apparent” equilibrium content of water ∼ (3.0 wt%). Because there was no significant measurable change in the tensile modulus between wet and dry samples, we cannot attribute these differences in L/D to changes in the resin's properties due to plasticizing by water. A small percentage of samples exposed at 65 °C did not show a significant increase in L/D, and in these cases the moisture produced a marked roughening of the fiber surface along the fiber/matrix interface. One possible explanation is that the attack by moisture degrades the interface, thus reducing its strength with a corresponding increase in the L/D. To varying degrees, however, the attack by moisture also degrades the E-glass fiber. This attack by moisture roughened the surfaces of the fibers and increased the distribution and/or size of the critical flaws, thus reducing both the strength of the fiber and the L/D. Based on our preliminary results, it appears that the singlefiber test has the potential to be useful for studying the durability of the resin/matrix interface providing that the influence of the environmental agent on all of the components of the model composite: resin, fiber, and interface/phase, is considered.

Electromechanical Study of Carbon Fiber Composites

1997 ◽  
Vol 500 ◽  
Author(s):  
Xiaojun Wang ◽  
Xuli Fu ◽  
D.D.L. Chung
Keyword(s):  
Residual Stress ◽  
Carbon Fiber ◽  
Fiber Composites ◽  
Single Fiber ◽  
Fiber Direction ◽  
Carbon Fiber Composites ◽  
Fiber Waviness ◽  
Pull Out ◽  
The Matrix ◽  
Fiber Matrix

ABSTRACTElectromechanical testing involving simultaneous electrical and mechanical measurements under load was used to study the fiber-matrix interface, fiber residual stress and marcelling (fiber waviness) in carbon fiber composites. The interface study involved single fiber pull-out while the fiber-matrix contact resistivity was measured. The residual stress study involved measuring the resistance of a single fiber embedded in the matrix while the fiber was tensioned at its exposed ends. The marcelling study involved measuring the resistance of a composite in the through-thickness direction while tension was applied in the fiber direction.

Strength and Interfacial Properties of Ceramic Composites

1986 ◽  
Vol 78 ◽  
Author(s):  
D. B. Narshall
Keyword(s):  
Interfacial Properties ◽  
Ceramic Composites ◽  
Interface Properties ◽  
Matrix Interface ◽  
Direct Measurements ◽  
Fiber Matrix Interface ◽  
Fiber Matrix

ABSTRACTResults of recent micromechanics analyses of the reinforcing influence of frictionally bonded fibers in ceramic composites are summnarized. Direct measurements of the fiber/matrix interface properties are also discussed.

Determination of Fiber/Matrix Interface Mechanical Properties in Brittle-Matrix Composites

1990 ◽  
Vol 194 ◽  
Author(s):  
Ronald J. Kerans ◽  
Paul D. Jero ◽  
Triplicane A. Parthasarathy ◽  
Amit Chatterjee
Keyword(s):  
Mechanical Properties ◽  
Ceramic Composites ◽  
Interface Properties ◽  
Matrix Composites ◽  
Matrix Interface ◽  
Intermetallic Matrix ◽  
Fiber Matrix Interface ◽  
Fiber Matrix ◽  
Intermetallic Matrix Composites

AbstractIt has been evident for some time that the mechanical properties of the fiber/matrix interface play an important role in determining the mechanical behavior of ceramic composites (for reviews, see [1], [2], and [3[). Recently there has been a growing interest in the role of the fiber/matrix interface in intermetallic matrix composites. While ceramic and intermetallic composites are certainly very different materials, understanding the behavior of one will provide insight into the other. Furthermore, the basic issues regarding the determination of interface properties are the same. The accuracy of micromechanics models of any composite system is dependent upon the accuracy of all the constituent and interface properties. It is far preferable to measure actual materials constants rather than test-specific quantities. The tests described here are intended to measure the interfacial shear strength (or mode II toughness) and the interfacial tensile strength. The objective of this work is to briefly outline a few of the approaches which are being evaluated for and applied to ceramic composites, and which may be of interest to investigators working in intermetallic composites.

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