A Mechanistic Approach to Matrix Cracking Coupled with Fiber–Matrix Debonding in Short-Fiber Composites

2005 ◽  
Vol 127 (3) ◽  
pp. 337-350 ◽  
Author(s):  
Ba Nghiep Nguyen ◽  
Brian J. Tucker ◽  
Mohammad A. Khaleel
Keyword(s):  
Damage Mechanics ◽  
Fiber Composite ◽  
Fiber Composites ◽  
Short Fiber ◽  
Matrix Cracking ◽  
Element Analysis ◽  
Pull Out ◽  
Stiffness Reduction ◽  
Mechanistic Approach ◽  
Fiber Matrix

A micro–macro mechanistic approach to damage in short-fiber composites is developed in this paper. At the microscale, a reference aligned fiber composite is considered for the analysis of the damage mechanisms such as matrix cracking and fiber–matrix debonding using the modified Mori–Tanaka model. The associated damage variables are defined, and the stiffness reduction law dependent on these variables is established. The stiffness of a random fiber composite containing random matrix microcracks and imperfect interfaces is then obtained from that of the reference composite, which is averaged over all possible orientations and weighted by an orientation distribution function. The macroscopic response is determined using a continuum damage mechanics approach and finite element analysis. Final failure resulting from saturation of matrix microcracks, fiber pull-out and breakage is modeled by a vanishing element technique. The model is validated using the experimental results found in literature as well as the results obtained for a random chopped fiber glass–vinyl ester system. Acoustic emission techniques were used to quantify the amount and type of damage during quasi-static testing.

Damage in Short-Fiber Composites: From the Microscale to the Continuum Solid

2004 ◽  
Author(s):  
Ba Nghiep Nguyen ◽  
Brian J. Tucker ◽  
Mohammad A. Khaleel
Keyword(s):  
Damage Mechanics ◽  
Continuum Damage Mechanics ◽  
Short Fiber ◽  
Micromechanical Modeling ◽  
Element Analysis ◽  
Pull Out ◽  
Stiffness Reduction ◽  
Mechanistic Approach ◽  
Final Failure ◽  
Element Technique

This paper proposes a multiscale mechanistic approach to damage in short-fiber polymer composites (SFPC). At the microscale, the damage mechanisms are analyzed using micromechanical modeling, and the associated damage variables are defined. The stiffness reduction law dependent on these variables is then established. The macroscopic response is determined using thermodynamics of continuous media, continuum damage mechanics and finite element analysis. Final failure resulting from saturation of matrix microcracks, fiber/matrix debonding, fiber pull-out and breakage is modeled by a vanishing element technique. The model was validated using the experimental data and results from literature, as well as those obtained from a random glass/vinyl ester system.

Predictions of the Mechanical Performance of Leaf Fiber Thermoplastic Composites by FEA

2021 ◽  
Author(s):  
Faris M. AL-Oqla
Keyword(s):  
Composite Materials ◽  
Cantilever Beam ◽  
Mechanical Performance ◽  
Natural Fiber ◽  
Fiber Composite ◽  
Fiber Composites ◽  
Fiber Types ◽  
Natural Fiber Composites ◽  
Pull Out ◽  
Structural Applications

The available potential plant waste could be worthy material to strengthen polymers to make sustainable products and structural components. Therefore, modeling the natural fiber polymeric-based composites is currently required to reveal the mechanical performance of such polymeric green composites for various green products. This work numerically investigates the effect of various fiber types, fiber loading, and reinforcement conditions with different polymer matrices towards predicting the mechanical performance of such natural fiber composites. Cantilever beam and compression schemes were considered as two different mechanical loading conditions for structural applications of such composite materials. Finite element analysis was conducted to modeling the natural fiber composite materials. The interaction between the fibers and the matrices was considered as an interfacial friction force and was determined from experimental work by the pull out technique for each polymer and fiber type. Both polypropylene and polyethylene were considered as composite matrices. Olive and lemon leaf fibers were considered as reinforcements. Results have revealed that the deflection resistance of the natural fiber composites in cantilever beam was enhanced for several reinforcement conditions. The fiber reinforcement was capable of enhancing the mechanical performance of the polymers and was the best in case of 20 wt.% polypropylene/lemon composites due to better stress transfer within the composite. However, the 40 wt.% case was the worst in enhancing the mechanical performance in both cantilever beam and compression cases. The 30 wt.% of polyethylene/olive fiber was the best in reducing the deflection of the cantilever beam case. The prediction of mechanical performance of natural fiber composites via proper numerical analysis would enhance the process of selecting the appropriate polymer and fiber types. It can contribute finding the proper reinforcement conditions to enhance the mechanical performance of the natural fiber composites to expand their reliable implementations in more industrial applications.

scholarly journals Study on the flexure performance of fine concrete sheets reinforced with textile and short fiber composites

2019 ◽  
Vol 275 ◽  
pp. 02006
Author(s):  
Qiao-chu Yang ◽  
Qin Zhang ◽  
Su-su Gong ◽  
San-ya Li
Keyword(s):  
Glass Fiber ◽  
Fiber Composite ◽  
Basalt Fiber ◽  
Fiber Composites ◽  
Short Fiber ◽  
Calcium Carbonate Whisker ◽  
Flexural Tests ◽  
Short Fiber Composite ◽  
Fiber Mesh ◽  
Concrete Matrix

In order to study the influences of the contents of short fiber on the mechanical properties of concrete matrix, the properties of compressive, flexure and splitting of concrete matrix reinforced by alkali resistant glass fiber and calcium carbonate whisker were tested. To study the reinforced effect of different scale fibers on the flexure behavior of fine concrete sheets, the flexural tests of concrete sheet of fine concrete reinforced with basalt fiber mesh and short fiber composites were carried out. The results show that the properties of the compressive, flexure and splitting of fine concrete reinforced with appropriate amount of alkali resistant glass fiber and carbonate whisker are improved compared with that of concrete reinforced by one type of fiber. The flexure properties of the concrete sheets are improved obviously when continuous fiber textile and short fiber composite are adopted to reinforce.

A New Theory for the Debonding of Discontinuous Fibers in an Elastic Matrix

1989 ◽  
Vol 170 ◽  
Author(s):  
Christopher K. Y. Leung ◽  
Victor C. Li
Keyword(s):  
Fiber Length ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Interfacial Strength ◽  
Fiber Composites ◽  
Short Fiber ◽  
Fiber Volume ◽  
Physical Reason ◽  
Pull Out

AbstractThe mechanical properties of fiber composites are strongly influenced by the debonding of fibers. When an embedded fiber is loaded from one end, debonding can occur at both the loaded end and the embedded end. Existing theories neglect the possibility of debonding from the embedded end and are thus limited in applications to cases with low fiber volume fraction, low fiber modulus, high interfacial strength/interfacial friction ratio or short fiber length. A new twoway fiber debonding theory, which can extend the validity of one-way debonding theories to all general cases, has recently been developed. In this paper, the physical reason for the occurrence of two-way debonding is discussed. The limit of validity for one-way debonding theories is considered. One-way and two-way debonding theories are then compared with respect to the prediction of composite behaviour. The determination of interfacial parameters from the fiber pull-out test will also be described.

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