Development of an Adhesion Test for Characterizing the Interface Fiber/Polymer Matrix

2012 ◽  
Vol 498 ◽  
pp. 210-218 ◽  
Author(s):  
Bouchra Hassoune-Rhabbour ◽  
Laurence Poussines ◽  
Valérie Nassiet

There are several models on the relationship structures and properties of the composite fiber / matrix interface [1]. Including literature proposes the development of micromechanical tests suitable for assessing the shear strength of the interface fiber / polymer matrix. The first test which allowed to characterize the fiber / matrix interface is the pull-out test developed by Broutman [2]. It consists in extracting the fiber from the matrix that can be in block form, gout or disk of resin. To reduce the variation in results due to the geometries used, it was agreed to use a drop of resin with small dimensions. The test is to characterize the fiber / matrix interface of natural thermosetting or thermoplastic by determining the shear stress.

1999 ◽  
Author(s):  
Robert C. Wetherhold ◽  
Joachim Bös

Abstract Ductile reinforcements can supply fracture toughness to a polymer matrix by pulling out and by plastically deforming. In the case of metal reinforcements that are not in a toughened condition, there may be more toughening to be gained when the fibers remain in the matrix and plastically deform rather than pulling out. These fibers can be said to have an unused plastic potential. When these fibers bridge a crack, their plastic deformation causes a rapid rise in the force which is trying to pull out the fiber. Because of this, the shape of the fiber must be adjusted along its length if it is to remain anchored and contribute its plastic work. The use of anchored, ductile fibers provides a new design axis that brings new possibilities not achievable by the current research focus on the fiber-matrix interface. This paper describes the experimental pullout of aligned ductile fibers from a polymer matrix, and indicates the effect of the shape and embedded length of the fiber on the toughness increase of the composite. Anchored, plastically deforming fibers are shown to provide a major improvement to the toughening. Even for unoptimized ductile fibers, the calculated toughening improvement equals or exceeds the toughening available from current short glass or graphite fibers.


Scanning ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Enze Jin ◽  
Denghao Ma ◽  
Zeshuai Yuan ◽  
Wenting Sun ◽  
Hao Wang ◽  
...  

Here, we show that when the oxidation treatment temperature exceeded 600°C, the tensile strength of SiC/SiC begins to decrease. Oxidation leads to the damages on the PyC fiber/matrix interface, which is replaced by SiO2 at higher temperature. The fracture mode converts from fiber pull-out to fiber-break as the fiber/matrix interface is filled with SiO2. Oxidation time also plays an important role in affecting the tensile strength of SiC/SiC. The tensile modulus decreases with temperature from RT to 800°C, then increases above 800°C due to the decomposition of remaining CSi x O y and crystallization of the SiC matrix. A special surface densification treatment performed in this study is confirmed to be an effective approach to reduce the oxidation damages and improve the tensile strength of SiC/SiC after oxidation.


1994 ◽  
Vol 365 ◽  
Author(s):  
Hassan Mahfuz ◽  
A.K.M. Ahsan Mian ◽  
Uday K. Vaidya ◽  
Timothy Brown ◽  
Shaik Jeelani

ABSTRACTA 3D-unit cell for 0/90 laminated composites has been developed to predict the composite behavior under longitudinal tensile loading condition. 3D contact element has been used to model the fiber matrix interface. Two interface conditions, namely, infinitely strong and weakly bonded, are considered in the analysis. Both large displacement and plastic strain behavior for the matrix are considered to account for the geometric and material non-linearities. Investigations were carried out at three temperatures to compare the composite response obtained from mechanical tests at those temperatures. Stress-strain behavior and the local stress distributions at the fiber as well as at the matrix are presented, and their effects on the failure of the interface are discussed in the paper. The material under investigation was SiCf/Si3N4.


2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Carlos Medina ◽  
Eduardo Fernandez ◽  
Alexis Salas ◽  
Fernando Naya ◽  
Jon Molina-Aldereguía ◽  
...  

The mechanical properties of the matrix and the fiber/matrix interface have a relevant influence over the mechanical properties of a composite. In this work, a glass fiber-reinforced composite is manufactured using a carbon nanotubes (CNTs) doped epoxy matrix. The influence of the CNTs on the material mechanical behavior is evaluated on the resin, on the fiber/matrix interface, and on the composite. On resin, the incorporation of CNTs increased the hardness by 6% and decreased the fracture toughness by 17%. On the fiber/matrix interface, the interfacial shear strength (IFSS) increased by 22% for the nanoengineered composite (nFRC). The influence of the CNTs on the composite behavior was evaluated by through-thickness compression, short beam flexural, and intraply fracture tests. The compressive strength increased by 6% for the nFRC, attributed to the rise of the matrix hardness and the fiber/matrix IFSS. In contrast, the interlaminar shear strength (ILSS) obtained from the short beam tests was reduced by 8% for the nFRC; this is attributed to the detriment of the matrix fracture toughness. The intraply fracture test showed no significant influence of the CNTs on the fracture energy; however, the failure mode changed from brittle to ductile in the presence of the CNTs.


Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4603
Author(s):  
Marfa Camargo ◽  
Eyerusalem Adefrs Taye ◽  
Judith Roether ◽  
Daniel Tilahun Redda ◽  
Aldo Boccaccini

The use of ecological materials for building and industrial applications contributes to minimizing the environmental impact of new technologies. In this context, the cement and geopolymer sectors are considering natural fibers as sustainable reinforcement for developing composites. Natural fibers are renewable, biodegradable, and non-toxic, and they exhibit attractive mechanical properties in comparison with their synthetic fiber counterparts. However, their hydrophilic character makes them vulnerable to high volumes of moisture absorption, thus conferring poor wetting with the matrix and weakening the fiber–matrix interface. Therefore, modification and functionalization strategies for natural fibers to tailor interface properties and to improve the durability and mechanical behavior of cement and geopolymer-based composites become highly important. This paper presents a review of the physical, chemical and biological pre-treatments that have been performed on natural fibers, their results and effects on the fiber–matrix interface of cement and geopolymer composites. In addition, the degradation mechanisms of natural fibers used in such composites are discussed. This review finalizes with concluding remarks and recommendations to be addressed through further in-depth studies in the field.


Author(s):  
I. Corvin ◽  
H. Morrow ◽  
O. Johari ◽  
N. Parikh

A significant amount of research has been done in the past few years in the development of suitable composite materials in general and on boron fiber-aluminum matrix composites in particular. The mechanical properties of the composite depend on the structures and strengths of the matrix and fibers; on the amount, distribution, and surface characteristics of the fibers; and on the quality of the bond at the fiber-matrix interface. The results presented here illustrate the application of the SEM in studying the structure of the fiber-matrix interface and the fracture features of boron and aluminum.


2000 ◽  
Vol 629 ◽  
Author(s):  
G. A. Holmes ◽  
R. C. Peterson

ABSTRACTFiber-matrix interface strength is known to be a critical factor in controlling the long-term performance of structural composites. This parameter is often obtained by using the average fragment length data generated from the single-fiber fragmentation test (SFFT). The interfacial shear strength is then determined by using this data in a micro-mechanics model that describes the shear-stress transfer process between the matrix and the fiber. Recently, a non-linear viscoelastic micro-mechanics model was developed to more accurately account for the matrix material properties. This new model indicates that the interface strength is dependent on the testing rate. Experimentally, it has been shown that the final fragment length distribution in some systems is dependent on the testing rate. However, data analysis using the new model indicates that the distribution change with testing rate is promoted by the presence of high stress concentrations at the end of the fiber fragments. From the model, these stress concentrations were found to exist at very low strain values. Experimentally, the fragment distributions obtained from specimens tested by different testing rates were found to be significantly different at strain values well below the strain values required to complete the test. These results are consistent with the research of Jahankhani and Galiotis and finite element calculations performed by Carrara and McGarry. These authors concluded that stress concentrations can promote failure of the fiber-matrix interface on the molecular level. Our results support this conclusion. In addition, our research results suggest that altering the SFFT testing rate can lower the magnitude of these stress concentrations and minimize failure of the fiber-matrix interface.


2014 ◽  
Vol 565 ◽  
pp. 14-19
Author(s):  
Gergis W. William ◽  
Samir N. Shoukry ◽  
Jacky C. Prucz

This paper presents two new 3D finite element Multi Fiber Models (MFM) that account for the effects of neighboring fibers on the stress distribution over fiber-matrix interface. One model assumes a hexagonal packing pattern of the neighboring fibers whereas the other assumes that the neighboring fibers are packed in a square pattern. Two scenarios regarding the contact surface between the fiber and the matrix are considered: the first one assumes no bond over the interface while in the other one the interface is perfectly bonded. The cooling process of the composite was simulated and then a transverse loading is applied to the composite. The results indicate that packing system and the characteristics of the fiber-matrix interface greatly influence the magnitude of the residual stresses developed in the matrix.


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