Micromechanical Modeling of Composites Fracture

1995 ◽  
Author(s):  
V. Kobelev
Keyword(s):  
Generating Functions ◽  
Infinite System ◽  
Mixed Boundary ◽  
Fiber Reinforced Composites ◽  
Micromechanical Modeling ◽  
Reinforced Composites ◽  
System Of Difference Equations ◽  
Design Problems ◽  
Main Emphasis

Abstract The paper considers the new micromechanical models of fracture of fiber-reinforced composites. The main emphasis is made on the determination of the exact analytical solutions of appearing fracture problems, which allow derivation of the closed functional formulas for limit fracture stresses. These expressions are suited for subsequent use in the formulations of optimal design problems. The model presented here describes the deformation and tearing of cloth. The material under study is made up of two families of orthogonal fibers. The object of investigation is the distribution of stresses in the neighborhood of the end of a semi-infinite tear. The description of the stress-strain state in the neighborhood of the end of the tear reduces to the solution of a mixed boundary-value problem for an infinite system of difference equations. When cast in terms of generating functions for an infinite vector of unknowns, the problem reduces to a RIEMANN-HELBERT problem. The analytical solution to the problem shows that the character of tearing of the material depends critically on the stresses in the fibers parallel to the direction of the tear: if the fibers parallel to the tear are stretched, then a finite rip in the material has an elliptical shape and the asymptotic behavior of the stresses around the end of the tear is similar to behavior of a solid elastic body with a crack. Conversely, if there is no stretching of the fibers parallel to the tear, then the sides of the tear intersect at a right angle, and the first unbroken fiber bears a considerably larger load than when stresses in parallel fibers are absent.

scholarly journals Void and Moisture Content of Fiber Reinforced Composites

2021 ◽  
Vol 87 (3) ◽  
pp. 78-93
Author(s):  
Nurul Zuhairah Mahmud Zuhudi ◽  
Afiq Faizul Zulkifli ◽  
Muzafar Zulkifli ◽  
Ahmad Naim Ahmad Yahaya ◽  
Nurhayati Mohd Nur ◽  
...  
Keyword(s):  
Moisture Content ◽  
Short Review ◽  
Fiber Reinforced Composites ◽  
Moisture Determination ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Mechanical Performances ◽  
Future Work ◽  
Selection Of

In this paper, a short review on the void and moisture content studies of fiber reinforced composites for both, synthetic and natural based fibers are presented. The review summarized the research papers in which include experimental and theoretical works that related to the void and moisture content studies. In addition to that, this review paper highlighting a few research studies conducted in literature on the effects of the void and moisture on the mechanical performances of the composite. Few common measurement methods used for the void and moisture determination are discussed here. The aims of this short review, mainly to capture the trend ranging from the recent five years back and summarize the various studies and also to compare and conclude the most common method for the determination of the void and moisture content. This paper is mainly providing a baseline in the selection of the methods for the future work of the author’s work with regard to the reduction of the presence of voids and moisture occur during the impregnation process of fiber reinforced composites, especially when using natural-based fiber.

Micromechanical modeling of fiber reinforced composites based on elastoplasticity and its application for 3D braided glass/Kevlar composites

2007 ◽  
Vol 28 (6) ◽  
pp. 722-732 ◽  
Author(s):  
Ji Hoon Kim ◽  
Hansun Ryou ◽  
Myoung-Gyu Lee ◽  
Kwansoo Chung ◽  
Jae Ryoun Youn ◽  
...  
Keyword(s):  
Fiber Reinforced Composites ◽  
Micromechanical Modeling ◽  
Reinforced Composites ◽  
Fiber Reinforced

A Critical Evaluation of the Use of the Microbond Method for Determination of Composite Interfacial Properties

1989 ◽  
Vol 170 ◽  
Author(s):  
Rebecca A. Haaksma ◽  
Marilyn J. Cehelnik
Keyword(s):  
Interfacial Adhesion ◽  
Test Procedure ◽  
Critical Evaluation ◽  
Adhesive Bond ◽  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Microbond Test ◽  
Application Techniques ◽  
Matrix Heterogeneity

AbstractThe microbond method has been applied with increased frequency to characterize interfacial adhesion in fiber reinforced composites. Nevertheless, a number of serious questions remain regarding the interpretation of experimental data. This paper addresses material and experimental variables in the microbond test procedure including the cure behavior of thermoset test specimens, matrix heterogeneity, locus of failure in test specimens and load application techniques. The theoretical basis for the method is examined by viewing experimental results in terms of existing theoretical interpretations of interfacial failure. Conclusions are presented regarding the limitations and the potential of the microbond method for determining fiber/matrix adhesive bond strength.

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.

“Y Contrast” of Single Shell Carbon Nanotubes: Determination Of Young’s Modulus by Observing Thermal Vibrations

1999 ◽  
Vol 5 (S2) ◽  
pp. 676-677
Author(s):  
M.M.J. Treacy ◽  
A. Krishnan ◽  
E. Dujardin ◽  
P.N. Yianilos ◽  
T.W. Ebbesen
Keyword(s):  
Carbon Nanotubes ◽  
Elastic Modulus ◽  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Multiwalled Nanotubes ◽  
Carbon Molecules ◽  
Thermal Vibrations ◽  
Graphite Sheets ◽  
Single Shell

Single shell carbon nanotubes are members of the Fullerene family of carbon molecules. Typically, single shell carbon nanotubes measure about 0.7 — 3 nm in diameter and are usually several microns in length. Structurally, they can be thought of as narrow graphite sheets that have been bent around the long axis and joined at opposite edges to form long seamless hollow shells of carbon. Typically, a hemispheroidal cap that contains exactly six 5-rings terminates each end, as shown in Figure 1.Graphite is known to have an in-plane elastic modulus of ∼1 TPa, one of the highest values known. Consequently, it is expected that single shell nanotubes should be very stiff — a fact that makes them potentially useful in fiber reinforced composites. However, because of their small size, it is impractical to measure their stiffness directly by conventional mechanical means. Recently, we demonstrated that thermal vibrations in freestanding multiwalled nanotubes could be used to estimate their stiffness [1].

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