Fiber-matrix Interface Damage Research Articles

Effect of Temperatures and Moisture Content on the Fracture Properties of Engineered Cementitious Composites (ECC).

This research will help to improve our understanding of the fracture properties of ECC at low temperatures (long-term low temperatures, freeze–thaw) and evaluate the safety properties of ECC under low-temperature conditions. Three levels of saturation (saturated, semi-saturated, and dry), four target temperatures (20, 0, −20, and −60 °C), and the effect of the coupled of the two on the mode I fracture properties of ECC were investigated. Then, we compared and analyzed the fracture properties of ECC loaded at 20 and −20 °C, after different freeze–thaw cycles (25, 50, 100 cycles), which were compared with saturated specimens without freeze–thaw at the four target temperatures to analyze the differences in low-temperature and freeze–thaw failure mechanisms. Temperatures and saturation have a significant effect on the fracture properties. Low temperatures and freeze–thaw treatments both decreased the nominal fracture energy of ECC. Distinct differences in matrix and fiber-matrix interface damage mechanisms have been discovered. Low temperatures treatment transforms ECC from a ductile to a brittle fracture mode. However, even after 100 freeze–thaw cycles, it remains ductile fractured. This study complements the deficiencies of ECC in low-temperature theoretical and experimental applications, and it sets the stage for a broad range of ECC applications.

A Numerical Study for Determining the Effect of Raffia, Alfa and Sisal Fibers on the Fiber-matrix Interface Damage of Biocomposite Materials

Background: Nowadays, natural fibers are used in all industrial fields, particularly in automotive technology and civil engineering. This great emergence is due to their biodegradability, recyclability and have no environmental effect. Objective: In this article, the effect of raffia, alfa and sisal fibers on the damage of biocomposite materials (raffia/PLA (polylactic acid), alfa/PLA and sisal/PLA), subjected to the same mechanical shear stress, has been investigated. Method: To calculate the damage to the interface, the genetic operator crossing is employed based on the fiber and matrix damage. Result: The results have shown that the raffia / PLA and alfa/PLA biocomposite materials are better mechanical properties compared to sisal / PLA, this observation has been confirmed by different values of interface damage of the biocomposite studied. Conclusion: The numerical results are similar and coincide perfectly with the results of Cox where he demonstrated that the Young's modulus of fibers improves the resistance of the interface. These conclusions are in very good agreement with our numerical data presented by the red cloud, and in good agreement with the work presented by Antoine Le Duigou et al. and Bodros et al. in which they have shown that natural fibers greatly improve the physical characteristics of composite materials.

Effect of Fiber-matrix Interface Decohesion on the Behavior of Thermoset and Thermoplastic Composites Reinforced with Natural Fibers: A Comparative Study

In this article, a comparative study was carried out on two types of thermosetting and thermoplastic matrices to study the effect of the fiber-matrix interface damage on the behavior of thermosetting and thermoplastic composites reinforced by the same natural alfa and wood fibers. The genetic modeling was based on the probabilistic formalism of Weibull. The results have been compared with those obtained by the nonlinear acoustic technique, the two results found to coincide perfectly. The numerical simulation also shows a good concordance with the real behavior of the materials studied, and shows that thermosetting composites are the most resistant to applied thermal stress by 21% compared to thermoplastic composites. Statistical analysis demonstrates that the correlation coefficient values found are very close to 1 (0.964 and 0.973), these values are very satisfactory, and confirm that the results obtained by the genetic model and the nonlinear acoustic technique are in very good agreement with the statistical analysis data. The experimental work presented by Antoine Le Duigou et al. and the work of Bodros et al. have shown that the use of natural fibers greatly improves the mechanical properties of composite materials.

Numerical characterization of the humidity effect on the fiber-matrix interface damage of hybrid composite material based on vinyl ester polymer matrix for engineering applications

Numerical characterization of the humidity effect on the fiber-matrix interface damage of hybrid composite material based on vinyl ester polymer matrix for engineering applications

The effects of plasticity mechanisms on micromechanics of composites with fiber waviness defects under compression

Micromechanics simulations of fiber-reinforced polymer-matrix composites with waviness defects are conducted to investigate the effect of constitutive model selection on the nucleation, evolution, and interaction of damage modes under in-plane compression. A 2D finite element model with fibers, matrix and fiber-matrix interfaces is used, considering damage modes at the constituent level (i.e., fiber-matrix interface damage, matrix plasticity, void nucleation and growth). Results show that the pressure-dependency of the polymer matrix is key for accurate predictions of strain localization in the fiber kinking mode and fiber-matrix interface crack behavior and extent at regions of waviness imperfections.

Theoretical study of the effect of the plant and synthetic fibers on the fiber-matrix interface damage of biocomposite materials based on PHAs (polyhydroxyalkanoates) biodegradable matrix

Theoretical study of the effect of the plant and synthetic fibers on the fiber-matrix interface damage of biocomposite materials based on PHAs (polyhydroxyalkanoates) biodegradable matrix

Modeling of Short Fiber Reinforced Polymer Composites Subjected to Multi‐block Loading

Short Fiber Reinforced Composite (SFRC) structures exhibit multiple microstructures (due to material flow during the process). They are generally subjected to variable amplitude loadings. In this context, a robust model is needed to predict fatigue life as a function of microstructure. In this paper, we propose a predictive micromechanical damage-based model allowing fatigue life prediction in the case of SFRC submitted to variable amplitude cyclic loading. An experimental study was firstly performed on Sheet Molding Compound (SMC) composite involving different microstructure configurations. Specimens were subjected to stress-controlled block loading. The influence of the order of the sequences was evaluated through Low-High amplitude (L-H) and High-Low amplitude (H-L) schemes. Damage accumulation is computed at the local scale to describe the evolution of the fiber-matrix interface damage until failure. A local failure criterion based on a critical damage state allowed predicting variable amplitude fatigue life as a function of microstructure. A good correlation was found between experimental and numerical results. Once the approach was validated, it has been used to model different useful variable amplitude loading schemes to emphasize the role of the loading sequence parameters and order.

A Nonlinear Analysis Interpretation of Off-Axis Test Results in Metal Matrix Composites

A unit-cell based micromechanics approach is used to perform nonlinear finite element analyses of off-axis tensile tests on an SCS-6/Ti-6Al-4V composite. The results are used in predicting the global deformation response of the composite that includes the effect of fiber-matrix interface damage. The predictions are compared with laboratory test data of uniaxial off-axis specimens. Based on the comparison, it is found that the procedure effectively predicts global composite response with reasonable accuracy under a general multiaxial stress state.

On the prediction of the bi-axial failure envelope of a UD CFRP composite lamina using computational micromechanics: Effect of microscale parameters on macroscale stress–strain behavior

A computational micromechanics based Finite Element (FE) analysis methodology is presented to predict the bi-axial failure envelope of a unidirectional (UD) carbon-epoxy composite ply. In order to estimate the effect of various microscale parameters that are influencing the macroscopic stress–strain behavior, under individual load cases, detailed numerical studies are conducted using a 3D RVE (Representative Volume Element) model. The constituent epoxy matrix plastic deformation in the RVE is captured using the linear Drucker-Prager plasticity model.The effect of the fiber–matrix interface damage, followed by frictional sliding of the constituent materials on the computed interface tractions is captured using the cohesive zone damage model combined with the Coulomb friction law, which is implemented into Abaqus using VUMAT. From the detailed FE analysis of the RVE under individual load cases, it is observed that the predicted macroscopic stress–strain behavior is sensitive to the fiber–matrix interface properties as well as the in-situ epoxy stress–strain behavior. Hence, using a coupled experimental-computational micromechanics approach the interface and the in-situ epoxy material properties are calibrated and validated. Using the calibrated interface and in-situ epoxy material properties, the bi-axial (transverse tension/transverse compression – in-plane shear) failure envelope of a UD composite ply is estimated. Comparing the predicted damage profiles and the failure envelope with the experimental results leads to good agreement and validates the proposed numerical methodology.

Study and modeling of thermomechanical properties of jute and Alfa fiber-reinforced polymer matrix hybrid biocomposite materials

In this paper, we have investigated and studied the effect of thermal stress on the fiber–matrix interface damage of three new hybrid biocomposite and biocomposite materials. Our genetic simulation based on Weibull probabilistic models showed that the jute–Alfa/PEEK (PEEK: thermoplastic matrix—polyetheretherketone) hybrid biocomposite material is more resistant to the mechanical and thermal stress applied comparing with the other biocomposites such as jute/PEEK and Alfa/PEEK with the same volume fraction used in our genetic model. Our results also show that natural fibers improve the physical properties of biocomposite materials, especially hybrid biocomposite materials. This finding is similar to that found by Antoine Le Duigou et al. where they have shown experimentally that the natural reinforcements greatly improve the properties of composite materials and also they have a very low environmental impact.

Experimental and numerical multi-scale approach for Sheet-Molding-Compound composites fatigue prediction based on fiber-matrix interface cyclic damage

In this paper, a multi-scale approach is proposed to predict the stiffness reduction of a Sheet-Molding-Compound (SMC) composite submitted to low cycle fatigue (until 2.105 cycles). Strain-controlled tensile fatigue tests (R = 0.1) are carried out at various strain ranges. Damage is investigated at both macroscopic and microscopic scales through the evolutions of Young’s modulus and SEM observations, after interrupted fatigue tests at different lifetime periods. The results show that the fatigue degradation of the composite is mainly controlled by fiber-matrix interface debonding. A quantitative analysis allows determining the threshold and kinetics of the fiber-matrix interface damage during cyclic loading as a function of the orientation of fibers. Moreover, a fiber-matrix interface damage criterion, taking into account the local cyclic normal and shear stresses at the interface, is introduced in the Mori and Tanaka approach in order to predict the loss of stiffness. The parameters of this local criterion are identified by reverse engineering on the basis of the experimental results described above. Finally, the predicted loss of stiffness is very consistent with the experimental results.

Computational micromechanics model for the analysis of fiber kinking in unidirectional fiber-reinforced polymers

A computational micromechanics (CMM) model is developed to analyze fiber kinking, which is a failure mechanism that takes place in fiber-reinforced composites when they are loaded under longitudinal compression. The CMM model consists of a single AS4 carbon fiber with an initial misalignment embedded in an 8552 polymer matrix. The deformation of the model is governed by periodic boundary conditions (PBC). The relatively simple CMM model enables the evaluation of the role played by initial misalignment of the fiber, shear yielding of the matrix and fiber-matrix debonding. A novel microscale experimental technique devoted to the characterization of the longitudinal compressive strength of the fibers, Xcf, is developed. By exercising the model and comparing it with several models in the literature, the nonlinear shear response of the composite lamina is shown to play a fundamental role not only in the prediction of the compressive strength Xc, but also during the post-peak regime in terms of residual stress σr and fiber rotation φ. Finally, the influence of the fiber-matrix interface damage (not considered in most other fiber kinking models) on the fiber kinking phenomenon is assessed through a parametric study.

Using Genetic Algorithms to study the Effect of Cellulose Fibers Ratio on the Fiber-Matrix Interface Damage of Biocomposite Materials

Background:In this article, we have studied the effect of cellulose fibers ratio on the fiber matrix interface damage of biocomposite materials based on a Polypropylene (PP) matrix.Methods:Few patents on the effect of cellulose fibers ratio on the fiber-matrix interface damage of biocomposite materials were published. We have investigated this damage, using a metaheuristic simulation based on the two Weibull probabilistic models which successively described the damage of the fiber and the matrix, our objective function is presented by the Cox model.Results:The results of our genetic modeling confirm that the level of damage is related to the mechanical stresses applied to the five studied materials Cotton-Polypropylene, Jute-Polypropylene, Flax- Polypropylene, Ramie-Polypropylene and Aramid-Polypropylene. Our genetic modeling indicates that the rate of cellulose in each fiber has a significant influence on the progressive degradation of the interface. The numerical simulation compared to the result obtained by genetic algorithm for the Aramid- Polypropylene composite shows that the level of degradation of the interface is greater compared to other biocomposite materials and that Cotton-Polypropylene has a very low interface damage compared to other biocomposites (82.5% cellulose).Conclusion:It can thus be said that the model correctly took into account the degradation phenomenon of a unidirectional composite and biocomposite and our calculations coincide perfectly with the conclusions of Antoine et al. who determined that the rate of cellulose in each fiber participates in the improvement of the mechanical properties of biocomposite materials.

Effects of hygrothermal and thermal aging on the low-velocity impact properties of carbon fiber composites

The effects of hygrothermal and thermal aging on the low-velocity impact properties of carbon fiber composites were systematically investigated by comparing the mass loss, morphologies, dynamic mechanical properties, and chemical structures of aged and non-aged specimens. The relationships between dent depth, damage area, residual compression strength, and impact energy were also discussed in detail. The obtained results showed that the non-aged composite featured good fiber-resin bonding, whereas hygrothermal and thermal aging led to fiber-matrix interface damage. For thermally aged samples, dent depth rapidly increased with impact energy above the inflection point, and the corresponding amplitude was greater than those observed for non-aged and hygrothermally aged specimens. Notably, hygrothermal and thermal aging did not affect the impact-induced damage morphology and the after-impact compression failure mode. At a constant impact energy, the damage area of thermally aged samples exceeded those of non-aged and hygrothermally aged ones; moreover, thermal aging exhibited greater influence on residual compressive strength than hygrothermal aging. Finally, whereas hygrothermal aging reduced the glass transition temperature (Tg) and did not induce the formation of new materials or the occurrence of chemical reactions, thermal aging resulted in increased Tg and was accompanied by the concomitant occurrence of oxidation reactions.

A computational micromechanics approach to evaluate elastic properties of composites with fiber-matrix interface damage

Computational micro-mechanics is employed in this work to evaluate effects of fiber-matrix interface damage on the elastic properties of polymer matrix composites with continuous glass fibers. It is assumed that damage affects local zones along the fiber and a sector on the perimeter around the fiber. Elastic modulii are evaluated using Finite Element analysis, for a range of values in damage parameters considered. The occurrence of bi-modular behavior, with differences in Young’s modulus under tension and compression, has been represented by contact without friction. Based on extensive parametric results, a Least Squares Method is employed to derive analytical expressions for each material property as a function of damage parameters. In most cases the elastic modulus has a nonlinear relation with the damage parameter in the length of the fiber, with the exception of the transverse elastic modulus under tension. The analytical expressions are used to couple micro and macro scales in an off-line scheme, without the need to perform in-time micro-scale computations.

Investigation by a Genetic Algorithm of the Effect of Moisture Diffusion on the Fiber Matrix Interface Damage of Graphite/Epoxy Nanocomposite

The Nanocomposite graphite/epoxy material has a high mechanical tensile strength after improving, its Young's modulus substantially strengthening the matrix with nano-particles of graphite. Few patents on the absorption of water by a nanocomposite were published. In this study, we investigate the influence of the absorption of water by the matrix on the fiber matrix interface damage. Our contribution is related to the development of an analytical model based on a genetic approach, using a basic model formalism of Weibull, the model of Cox and the laws diffusion of water in a polymer, where the damage was located by a non-linear acoustic technical. The results show that the rate humidity at 60% does not affect the fiber matrix interface damage of graphite epoxy nanocomposite compared to the other composite materials carbon-epoxy (T300/914) and Polyétheréthercétone (PEEK/APC2) whose interface damage increase to 0.2. Therefore, our findings revealed that the model worked well with the phenomenon of damage to unidirectional composite and nanocomposite materials. Keywords: Damage, fiber, genetic algorithm, interface, matrix, nanocomposite, non-linear acoustic technical.

Prediction by a Genetic Algorithm of the Fiber–Matrix Interface Damage for Composite Material. Part 1. Study of Shear Damage in Two Composites T300/914 and PEEK/APC2

We have conducted research on the effect of fiber arrangement on the optimization of the damage to the interface, recently published. We develop in this paper the evolution of the damage in the shearing direction by genetic algorithm. The results obtained by varying the shear rate of the interface of the two materials studied T300 and PEEK, show a good agreement between our genetic approach and the mathematical models presented by Cox and Weibull.

Prediction by a Genetic Algorithm of the Fiber–Matrix Interface Damage for Composite Material. Part 2. Study of Shear Damage in Graphite/Epoxy Nanocomposites

The objective in this paper is to apply the same genetic model as applied in Part 1 to optimizing the shear damage to the fiber–matrix interface of nanocomposite material graphite epoxy. The results show good agreement between the numerical simulation and the actual behavior of the chosen composite and nanocomposite materials, and these results are similar to those obtained by processing techniques of expanded graphite reinforced polymer nanocomposites made by Asma Yasmine. These results were confirmed by calculating the rate of damage with a genetic simulation.

Erratum to: Study of the Effect of Water Intake by the Matrix on the Optimization of the Fiber Matrix Interface Damage for a Composite Material by Genetic Algorithms

Erratum to: Study of the Effect of Water Intake by the Matrix on the Optimization of the Fiber Matrix Interface Damage for a Composite Material by Genetic Algorithms

Study of the Effect of Water Intake by the Matrix on the Optimization of the Fiber Matrix Interface Damage for a Composite Material by Genetic Algorithms

The objective of this paper is study the influence of the matrix swelling due to water on the damage of the fiber matrix interface of a composite material. The results obtained by a genetic approach based on Weibull probabilistic model, show good agreement between the simulation and the actual behavior of the two materials T300/914 and PEEK/APC2. Also the absorption of water by the matrix increases significantly the interface damage.