Journal articles: 'Micromechanics. Composite materials'

1

Garnich, M. R., and A. C. Hansen. "A Multicontinuum Approach to Structural Analysis of Linear Viscoelastic Composite Materials." Journal of Applied Mechanics 64, no. 4 (1997): 795–803. http://dx.doi.org/10.1115/1.2788984.

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A “multicontinuum” approach to structural analyses of composites is described. A continuum field is defined to represent each constituent material along with the traditional continuum field associated with the composite. Finite element micromechanics is used to establish relationships between composite and constituent field variables. These relationships uncouple the micromechanics from structural solutions and render an efficient means of extracting constituent information during the course of a finite element structural analysis. Equations are developed for the case of a linear elastic reinforcing material embedded in a linear viscoelastic matrix and verified by comparison with results of finite element micromechanics.

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Sertse, Hamsasew M., Johnathan Goodsell, Andrew J. Ritchey, R. Byron Pipes, and Wenbin Yu. "Challenge problems for the benchmarking of micromechanics analysis: Level I initial results." Journal of Composite Materials 52, no. 1 (2017): 61–80. http://dx.doi.org/10.1177/0021998317702437.

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Because of composite materials’ inherent heterogeneity, the field of micromechanics provides essential tools for understanding and analyzing composite materials and structures. Micromechanics serves two purposes: homogenization or prediction of effective properties and dehomogenization or recovery of local fields in the original heterogeneous microstructure. Many micromechanical tools have been developed and codified, including commercially available software packages that offer micromechanical analyses as stand-alone tools or as part of an analysis chain. With the increasing number of tools available, the practitioner must determine which tool(s) provides the most value for the problem at hand given budget, time, and resource constraints. To date, simple benchmarking examples have been developed in an attempt to address this challenge. The present paper presents the benchmark cases and results from the Micromechanical Simulation Challenge hosted by the Composites Design and Manufacturing HUB. The challenge is a series of comprehensive benchmarking exercises in the field of micromechanics against which such tools can be compared. The Level I challenge problems consist of six microstructure cases, including aligned, continuous fibers in a matrix, with and without an interphase; a cross-ply laminate; spherical inclusions; a plain-weave fabric; and a short-fiber microstructure with “random” fiber orientation. In the present phase of the simulation challenge, the material constitutive relations are restricted to linear thermoelastic. Partial results from DIGIMAT-MF, ESI VPS, MAC/GMC, finite volume direct averaging method, Altair MDS, SwiftComp, and 3D finite element analysis are reported. As the challenge is intended to be ongoing, the full results are hosted and updated online at www.cdmHUB.org .

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3

Gao, Zhanjun. "Reliability and micromechanics of Composite Materials." Advanced Composites Letters 1, no. 3 (1992): 096369359200100. http://dx.doi.org/10.1177/096369359200100302.

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A methodology is proposed to evaluate the reliability of composites. Micromechanical analysis is utilized as a basis for the representation of the effects of constituent properties on global response. The analysis is then combined with the models of structural reliability to study the influence of micro-level material parameters on reliability of composites under static loadings.

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Dunn, Martin L. "One-Dimensional Composite Micromechanics." International Journal of Mechanical Engineering Education 26, no. 1 (1998): 38–50. http://dx.doi.org/10.1177/030641909802600105.

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We present an easily understood, one-dimensional development of composite micromechanics that bridges the gap between the state of the art in composites research and composites education. By developing the general framework in a one-dimensional setting, a clear exposition of the basic ideas evolves. Exact analysis is carried out as far as possible, until one arrives at a natural point where assumptions must be introduced. The nature of the necessary assumptions is then clear and they have a simple physical interpretation. The connection between the framework presented here and traditional mechanics of materials analyses is discussed at length, as is a method by which the approach can be used in conjunction with an experimental programme to assess the validity of various assumptions. The general approach in one dimension leads naturally to the extension to two and three dimensions, along with the extension to analogous physical and thermomechanical properties.

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Marfia, S., and E. Sacco. "Micromechanics and Homogenization of SMA-Wire-Reinforced Materials." Journal of Applied Mechanics 72, no. 2 (2005): 259–68. http://dx.doi.org/10.1115/1.1839186.

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The aim of the paper is to develop a micromechanical model for the evaluation of the overall constitutive behavior of a composite material obtained embedding SMA wires into an elastic matrix. A simplified thermomechanical model for the SMA inclusion, able to reproduce the superelastic as well as the shape memory effect, is proposed. It is based on two assumptions: the martensite volume fraction depends on the wire temperature and on only the normal stress acting in the fiber direction; the inelastic strain due to the phase transformations occurs along the fiber direction. The two introduced hypotheses can be justified by the fact that the normal stress in the fiber direction represents the main stress in the composite. The overall nonlinear behavior of long-fiber SMA composites is determined developing two homogenization procedures: one is based on the Eshelby dilute distribution theory, the other considers the periodicity conditions. Numerical applications are developed in order to study the thermomechanical behavior of the composite, influenced by the superelastic and shape memory effects occurring in the SMA wires. Comparisons of the results obtained adopting the two homogenization procedures are reported. The influence of the matrix stiffness and of a prestrain in the SMA wires on the overall behavior of the composites is investigated.

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Laird, G., and T. C. Kennedy. "Micromechanics of composite materials under compressive loading." Engineering Fracture Mechanics 51, no. 3 (1995): 417–30. http://dx.doi.org/10.1016/0013-7944(94)00268-m.

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7

Lei, Yong-Peng, Hui Wang, and Qing-Hua Qin. "Micromechanical properties of unidirectional composites filled with single and clustered shaped fibers." Science and Engineering of Composite Materials 25, no. 1 (2018): 143–52. http://dx.doi.org/10.1515/secm-2016-0088.

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AbstractComputational micromechanics provides an efficient strategy to optimize composite materials by addressing the effect of different material and geometric parameters involved. In the present paper, the effective transverse elastic properties for periodic composite materials reinforced with single and clustered polygonal fibers are evaluated using the micromechanical finite element formulation subject to periodic displacement boundary conditions. The cross-sectional shapes of polygonal fibers are assumed to be triangular, square, pentagonal, hexagonal, octagonal, and circular to perform comprehensive investigation. By applying a periodic displacement constraint along the boundary of the representative unit cell of the composite to meet the requirement of straight-line constraint during the deformation of the unit cell, the computational micromechanical modeling based on homogenization technology is established for evaluating the effects of fiber shape and cluster on the overall properties. Subsequently, the micromechanical model is divided into four submodels, which are solved by means of the finite element analysis for determining the traction distributions along the cell boundary. Finally, the effective orthotropic elastic constants of composites are obtained using the solutions of the linear system of equations involving traction integrations to investigate the effects of fiber shape and cluster on the overall properties.

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Choudhry, RS, Kamran A. Khan, Sohaib Z. Khan, Muhammad A. Khan, and Abid Hassan. "Micromechanical modeling of 8-harness satin weave glass fiber-reinforced composites." Journal of Composite Materials 51, no. 5 (2016): 705–20. http://dx.doi.org/10.1177/0021998316649782.

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This study introduces a unit cell-based finite element micromechanical model that accounts for correct post cure fabric geometry, in situ material properties and void content within the composite to accurately predict the effective elastic orthotropic properties of 8-harness satin weave glass fiber-reinforced phenolic composites. The micromechanical model utilizes a correct post cure internal architecture of weave, which was obtained through X-ray microtomography tests. Moreover, it utilizes an analytical expression to update the input material properties to account for in situ effects of resin distribution within yarn (the yarn volume fraction) and void content on yarn and matrix properties. This is generally not considered in modeling approaches available in literature and in particular, it has not been demonstrated before for finite element micromechanics models of 8-harness satin weave composites. The unit cell method is used to obtain the effective responses by applying periodic boundary conditions. The outcome of the analysis based on the proposed model is validated through experiments. After validation, the micromechanical model was further utilized to predict the unknown effective properties of the same composite.

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Pindera, Marek-Jerzy, and Yogesh Bansal. "On the Micromechanics-Based Simulation of Metal Matrix Composite Response." Journal of Engineering Materials and Technology 129, no. 3 (2007): 468–82. http://dx.doi.org/10.1115/1.2744419.

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The response of metal matrix composites is affected by factors such as inclusion distribution and shape, inclusion/matrix interfacial bond, residual stresses, and fabrication-altered in situ matrix properties. These effects are studied using a finite-volume micromechanics model whose extensive modeling capabilities are sufficient to account for these diverse factors. A consistent micromechanics-aided methodology is developed for extracting the unknown in situ matrix plastic parameters using a minimum amount of experimental data. Subsequent correlation of the micromechanics-based predictions with carefully generated data on off-axis response of unidirectional boron/aluminum composite specimens under tensile and compressive axial loading validates the model’s predictive capability and quantifies the importance of each factor.

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Huang, Jin H., Ce Wen Nan, and Rui-Mu Li. "Micromechanics approach for effective magnetostriction of composite materials." Journal of Applied Physics 91, no. 11 (2002): 9261–66. http://dx.doi.org/10.1063/1.1475357.

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11

Aboudi, Jacob. "Micromechanics Prediction of Fatigue Failure of Composite Materials." Journal of Reinforced Plastics and Composites 8, no. 2 (1989): 150–66. http://dx.doi.org/10.1177/073168448900800203.

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12

Tekog˜lu, C., and T. Pardoen. "A micromechanics based damage model for composite materials." International Journal of Plasticity 26, no. 4 (2010): 549–69. http://dx.doi.org/10.1016/j.ijplas.2009.09.002.

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13

Buryachenko, V. A. "Multiparticle Effective Field and Related Methods in Micromechanics of Composite Materials." Applied Mechanics Reviews 54, no. 1 (2001): 1–47. http://dx.doi.org/10.1115/1.3097287.

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The numerous approaches used in micromechanics can be classified into four broad categories: perturbation methods, self-consistent methods of truncation of a hierarchy, variational methods, and the model methods. In detail we will consider the self-consistent methods applied to linear elastic problems, based on some approximate and closing assumptions for truncating of an infinite system of integral equations involved and their approximate solution. We consider multiparticle effective field methods, effective medium methods, the Mori-Tanaka method, differential methods and some others. This review article tends to concentrate on methods and concepts, their possible generalizations, and connections of different methods, rather than explicit results. In the framework of a unique scheme, we undertake an attempt to analyze the wide class of statical and dynamical, local and nonlocal, linear and nonlinear micromechanical problems of composite materials with deterministic (periodic and non-periodic) and random (statistically homogeneous and inhomogeneous, so-called graded) structures, containing coated or uncoated inclusions of any shape and orientation and subjected to coupled or uncoupled, homogeneous or inhomogeneous, external fields of different physical natures. The last section contains a discussion of prospects for future work. The article includes 540 references.

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14

Wang, Guannan, Qiang Chen, Mengyuan Gao, Bo Yang, and David Hui. "Generalized locally-exact homogenization theory for evaluation of electric conductivity and resistance of multiphase materials." Nanotechnology Reviews 9, no. 1 (2020): 1–16. http://dx.doi.org/10.1515/ntrev-2020-0001.

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AbstractThe locally-exact homogenization theory is further extended to investigate the homogenized and localized electric behavior of unidirectional composite and porous materials. Distinct from the classical and numerical micromechanics models, the present technique is advantageous by developing exact analytical solutions of repeating unit cells (RUC) with hexagonal and rhomboid geometries that satisfy the internal governing equations and fiber/matrix interfacial continuities in a point-wise manner. A balanced variational principle is proposed to impose the periodic boundary conditions on mirror faces of an RUC, ensuring rapid convergence of homogenized and localized responses. The present simulations are validated against the generalized Eshelby solution with electric capability and the finite-volume direct averaging micromechanics, where excellent agreements are obtained. Several micromechanical parameters are then tested of their effects on the responses of composites, such as the fiber/matrix ratio and RUC geometry. The efficiency of the theory is also proved and only a few seconds are required to generate a full set of properties and concomitant local electric fields in an uncompiled MATLAB environment. Finally, the related programs may be encapsulated with an input/output (I/O) interface such that even non-professionals can execute the programs without learning the mathematical details.

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15

Lagoudas, D. C., J. G. Boyd, and Z. Bo. "Micromechanics of Active Composites With SMA Fibers." Journal of Engineering Materials and Technology 116, no. 3 (1994): 337–47. http://dx.doi.org/10.1115/1.2904297.

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The study of the effective thermomechanical response of active fibrous composites with shape memory alloy (SMA) fibers is the subject of this work. A 3-D constitutive response for the SMA fibers is formulated first. To model thermomechanical loading path dependence, an incremental approach is used assuming that within each stress and temperature increment the volume fraction of the martensitic phase remains constant in the SMA fibers. The Mori-Tanaka averaging scheme is then used to give an estimate of the instantaneous effective thermomechanical properties in terms of the thermomechanical properties of the two phases and martensitic volume fraction. A unit cell model for a periodic active composite with cubic and hexagonal arrangement of fibers is also developed to study the effective properties using finite element analysis. It is found that since the fibers and not the matrix undergo the martensitic phase transformation that induces eigenstrains, the Mori-Tanaka averaging scheme accurately models the thermomechanical response of the composite, relative to the finite element analysis, for different loading paths. Specific results are reported for the composite pseudoelastic and shape memory effect for an elastomeric matrix continuous SMA fiber composite.

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16

Antin, Kim-Niklas, Anssi Laukkanen, Tom Andersson, Danny Smyl, and Pedro Vilaça. "A Multiscale Modelling Approach for Estimating the Effect of Defects in Unidirectional Carbon Fiber Reinforced Polymer Composites." Materials 12, no. 12 (2019): 1885. http://dx.doi.org/10.3390/ma12121885.

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A multiscale modelling approach was developed in order to estimate the effect of defects on the strength of unidirectional carbon fiber composites. The work encompasses a micromechanics approach, where the known reinforcement and matrix properties are experimentally verified and a 3D finite element model is meshed directly from micrographs. Boundary conditions for loading the micromechanical model are derived from macroscale finite element simulations of the component in question. Using a microscale model based on the actual microstructure, material parameters and load case allows realistic estimation of the effect of a defect. The modelling approach was tested with a unidirectional carbon fiber composite beam, from which the micromechanical model was created and experimentally validated. The effect of porosity was simulated using a resin-rich area in the microstructure and the results were compared to experimental work on samples containing pores.

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Araki, S., and K. Saito. "Micromechanics of Stiffness Damage in Ceramic-Based Fiber-Reinforced Composites." International Journal of Damage Mechanics 11, no. 3 (2002): 205–22. http://dx.doi.org/10.1106/105678902026410.

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The micromechanical analysis is performed to elucidate the stiffness reduction damage in the ceramic/ceramic composite whose matrix rupture strain is smaller than that of fibers. It is assumed that damage mechanism in the composite consists mainly of crack bridging fiber and interfacial sliding between the matrix and fibers. Energy release rate for a matrix crack and energy dissipation by the interfacial sliding was formulated by means of the inclusion modeling in micromechanics. Macroscopic stiffness at the given applied stress was derived in terms of the current lengths of matrix cracks. Finally, applicability of a parameter of damage accumulation in the material and its effect on macroscopic stiffness were discussed by the use of macroscopic stress-strain curves.

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Bednarcyk, Brett A., Jacob Aboudi, and Steven M. Arnold. "Micromechanics of composite materials governed by vector constitutive laws." International Journal of Solids and Structures 110-111 (April 2017): 137–51. http://dx.doi.org/10.1016/j.ijsolstr.2017.01.033.

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Yifeng, Zhong, Chen Lei, Wenbin Yu, and Zhou Xiaoping. "Variational asymptotic micromechanics modeling of heterogeneous magnetostrictive composite materials." Composite Structures 106 (December 2013): 502–9. http://dx.doi.org/10.1016/j.compstruct.2013.06.018.

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Alazwari, Mashhour A., and Singiresu S. Rao. "Interval-based uncertainty models for micromechanical properties of composite materials." Journal of Reinforced Plastics and Composites 37, no. 18 (2018): 1142–62. http://dx.doi.org/10.1177/0731684418788733.

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Extensive work has been done in the past few decades to quantify the uncertainties associated with the micromechanics of composite materials in the presence of uncertainties in constituent material properties using probabilistic approaches. However, the probabilistic approaches require a knowledge of the probability distributions of the input parameters which are not known in most cases. This work presents interval-based uncertainty analysis using probabilistic approach with three sigma band about the mean, interval analysis method and the universal grey system (number) theory. Since the interval analysis predicts wider ranges and, in some cases, might violate the physical laws of the problem, the truncation-based interval analysis is presented to overcome the overestimation caused in the computed quantities by the so-called dependency problem associated with the interval analysis. The uncertainties exhibited in the micromechanics characteristics of composite materials due to the presence of uncertainties in the constituent material properties are investigated. The propagation of these uncertainties to the response characteristics of an angle-ply lamina is also studied. In the numerical study, two types of composite materials are considered – the graphite/epoxy and glass/epoxy systems – to demonstrate and compare the influence of the uncertainty models on the results. This work shows that improved and more meaningful results can be obtained using the universal grey system theory compared to the interval analysis, truncation-based interval analysis and probabilistic method for the micromechanics of composite materials and the response of an angle-ply lamina when the fiber and matrix properties are uncertain.

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HUANG, ZHUPING, YONGQIANG CHEN, and SHU-LIN BAI. "AN ELASTOPLASTIC CONSTITUTIVE MODEL FOR POROUS MATERIALS." International Journal of Applied Mechanics 05, no. 03 (2013): 1350035. http://dx.doi.org/10.1142/s175882511350035x.

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A micromechanics-based elastoplastic constitutive model for porous materials is proposed. With an assumption of modified three-dimensional Ramberg–Osgood equation for the compressible matrix material, the variational principle based on a linear comparison composite is applied to study the effective mechanical properties of the porous materials. Analytical expressions of elastoplastic constitutive relations are derived by means of micromechanics principles and homogenization procedures. It is demonstrated that the derived expressions do not involve any additional material constants to be fitted with experimental data. The model can be useful in the prediction of mechanical properties of elastoplastic porous solids.

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Chamis, Christos C. "Simplified Composite Micromechanics For Predicting Microstresses." Journal of Reinforced Plastics and Composites 6, no. 3 (1987): 268–89. http://dx.doi.org/10.1177/073168448700600305.

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23

Mirdehghan, Abolfazl, Hooshang Nosraty, Mahmood M. Shokrieh, Roohallah Ghasemi, and Mehdi Akhbari. "Micromechanical modelling of the compression strength of three-dimensional integrated woven sandwich composites." Journal of Industrial Textiles 48, no. 9 (2018): 1399–419. http://dx.doi.org/10.1177/1528083718764909.

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This paper is concerned with a theoretical and experimental verification of a micromechanical model of newly developed sandwich panels denoted as 3D integrated woven sandwich composite panels. The integrated hollow core was made of a pile of 3D bars with a special configuration. Integrated woven sandwich composite panels consist of two fabric faces which were interwoven by pile fibers and therefore a very high skin core debonding resistance was obtained. With the objective of qualifying the mechanical properties of these structures, fairly extensive experimental research was carried out by investigators. Although some numerical methods have been developed to predict the mechanical behaviors of these structures, there are less analytical models in this area. Due to the computational difficulties and the time consuming nature of the finite element method, in the present study, a new micromechanics analytical model has been suggested for predicting the compressive strength of integrated woven sandwich composites. In order to evaluate the proposed model, fabricated samples with different pile heights and pile distribution densities were subjected to flatwise compression tests. The results show that compressive properties of integrated woven sandwich composite panels are decreased with the increase of core heights and increased greatly with that of the pile density. Furthermore, the micromechanics model reasonably predicted the compression strength, and there is a good agreement between the experimental data and model predictions.

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24

Brayshaw, James B., and Marek-Jerzy Pindera. "The Effect of Matrix Constitutive Model on Residual Thermal Stresses in MMC." Journal of Engineering Materials and Technology 116, no. 4 (1994): 505–11. http://dx.doi.org/10.1115/1.2904320.

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A thermomechanical analysis of advanced composites in a wide temperature range is presented. This analysis is based on the micromechanics method of cells. An incremental formulation of the micromechanics model is developed to facilitate the use of various inelastic constitutive theories. These theories incorporate time-dependent and temperature-dependent features for modeling different types of metal matrices. The constitutive models include the Bodner-Partom unified theory of viscoplasticity, the incremental plasticity model, and a power-law creep model. The effect of the cooling rate, taking into account temperature-dependent matrix properties, on residual thermal stresses is subsequently investigated for a SiC/Ti composite using the different models for the matrix phases. Predictions generated using the micromechanics method are compared with available results of finite-element analysis.

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25

Hahn, H. T., and K. S. Kim. "Hygroscopic Effects in Aramid Fiber/Epoxy Composite." Journal of Engineering Materials and Technology 110, no. 2 (1988): 153–57. http://dx.doi.org/10.1115/1.3226024.

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Hygroscopic effects in aramid fiber composites are assessed semi-empirically using a combination of micromechanics models and experimental data. It is pointed out that the in situ moisture concentration of the fiber should be known as it affects diffusional as well as expansional properties. The micromechanics models for moisture absorption indicate that the in situ moisture concentration is lower than the bulk value. The interfacial radial stress can be tensile in wet unidirectional composites, and ply cracks are shown to increase moisture diffusion in laminates.

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Pant, R. H., and R. F. Gibson. "Analysis and Testing of Dynamic Micromechanical Behavior of Composite Materials at Elevated Temperatures." Journal of Engineering Materials and Technology 118, no. 4 (1996): 554–60. http://dx.doi.org/10.1115/1.2805956.

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This paper describes the use of a recently developed high temperature impulse-frequency response apparatus to directly measure dynamic modulus and internal damping of high temperature composite materials, matrix materials, and reinforcing fibers as a function of temperature. An extensional vibration test was used for determination of the complex Young’s modulus of fiber specimens as a function of temperature. A flexural vibration test was used for determination of the complex flexural modulus of matrix and unidirectional composite specimens (0 and 90 deg fiber orientations) as a function of temperature. These results were obtained from tests done on two different fiber reinforced composite materials: boron/epoxy (B/E) and Silicon Carbide/Ti-6Al-4V (SiC/Ti). The results from these tests were then used to assess the validity of micromechanics predictions of composite properties at elevated temperatures. Micromechanics predictions of composite moduli and damping at elevated temperatures show good agreement with measured values for the 0 deg case (longitudinal) but only fair agreement for the 90 deg case (transverse). In both cases, the predictions indicate the correct trends in the properties.

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Li, Jiang Yu, and Martin L. Dunn. "Micromechanics of Magnetoelectroelastic Composite Materials: Average Fields and Effective Behavior." Journal of Intelligent Material Systems and Structures 9, no. 6 (1998): 404–16. http://dx.doi.org/10.1177/1045389x9800900602.

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Skrinjar, Olle, and Per-Lennart Larsson. "On the micromechanics of die compaction of composite powder materials." International Journal of Materials Research 102, no. 4 (2011): 406–12. http://dx.doi.org/10.3139/146.110499.

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Zhang, Z. K., and A. K. Soh. "Micromechanics predictions of the effective moduli of magnetoelectroelastic composite materials." European Journal of Mechanics - A/Solids 24, no. 6 (2005): 1054–67. http://dx.doi.org/10.1016/j.euromechsol.2005.07.005.

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Costanzo, F. "Micromechanics and homogenization of inelastic composite materials with growing cracks." Journal of the Mechanics and Physics of Solids 44, no. 3 (1996): 333–70. http://dx.doi.org/10.1016/0022-5096(95)00082-8.

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Wang, Su Su, and Xiaohong Chen. "Computational Micromechanics for High-Temperature Constitutive Equations of Polymer-Matrix Composites With Oxidation Reaction, Damage, and Degradation." Journal of Engineering Materials and Technology 128, no. 1 (2005): 81–89. http://dx.doi.org/10.1115/1.2132377.

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The proper determination of high-temperature constitutive properties and damage of polymer-matrix composites (PMC) in an aggressive environment is critical in high-speed aircraft and propulsion material development, structural integrity, and long-term life prediction. In this paper, a computational micromechanics study is conducted to obtain high-temperature constitutive properties of the PMC undergoing simultaneous thermal oxidation reaction, microstructural damage, and thermomechanical loading. The computational micromechanics approach follows the recently developed irreversible thermodynamic theory for polymer composites with reaction and microstructural change under combined chemical, thermal, and mechanical loading. Proper microstructural modeling of the PMC is presented to ensure that reaction activities, thermal and mechanical responses of the matrix, fibers, and fiber-matrix interface are fully addressed. A multiscale homogenization theory is used in conjunction with a finite element representation of material and reaction details to determine continuous evolution of composite microstructure change and associated degradation of the mechanical and physical properties. Numerical examples are given on a commonly used G30-500/PMR15 composite for illustration.

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Duva, J. Mark, Jacob Aboudi, and Carl T. Herakovich. "A Probabilistic Micromechanics Model for Damaged Composites." Journal of Engineering Materials and Technology 118, no. 4 (1996): 548–53. http://dx.doi.org/10.1115/1.2805955.

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The generalized method of cells, an interfacial constitutive model and a probabilistic model are combined to yield an approach for modeling the stress-strain response of fibrous composites with fiber/matrix interfacial damage. It has been shown that the limitations of a single repeating cell in representing the response of a composite with debonding interfaces can be overcome through the introduction of a probabilistic modelling approach based upon an effective interfacial strength. This approach is used to recover the transverse tensile and axial shear response of unidirectional silicon-carbide/titanium as measured in the laboratory.

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Snipes, J. S., C. T. Robinson, and S. C. Baxter. "Effects of scale and interface on the three-dimensional micromechanics of polymer nanocomposites." Journal of Composite Materials 45, no. 24 (2011): 2537–46. http://dx.doi.org/10.1177/0021998311401104.

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Nanocomposite materials hold the power to revitalize and revolutionize the field of composite materials. Nanoscaled, even common materials can exhibit strikingly different material properties from the bulk counterparts. If these properties can be accessed at the bulk scale, not only can materials be better tailored to suit various applications, but the possibility of designing multi-functional materials expands exponentially. In this study, the Generalized Method of Cells (GMC) micromechanics model is used to model 3D nanoscale composite architecture, including an interfacial region between the included and matrix phases, and predict the effective viscoelastic properties of a gold nanorod, polymer matrix, nanocomposite. Scale is introduced by referencing the dimensions of the interface to those of the nanorods. Comparisons are made of micromechanical response based on volume fraction and number density, highlighting the scale effects resulting from the high surface area to volume ratio of nanoparticles. Effective composite viscoelastic properties were developed, for static creep, for varying interfacial elastic stiffnesses. These experiments suggest that an elastically stiff interface greatly increases the stiffness of the polymer in response to an ‘instantaneous’ step load, reduces the rapid creep response, and results in a rapid leveling off of the time-dependent strain curves. The response of the composite to increasing stiffness of the interface region eventually reaches a plateau or threshold value, where further increases in the stiffness of the interface produces negligible increases in stiffness, or further reduction in creep response.

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Biscani, Fabio, Yao Koutsawa, Salim Belouettar, and Erasmo Carrera. "Effective Properties of Electro-Elastic Composites with Multi-Coating Inhomogeneities." Advanced Materials Research 93-94 (January 2010): 190–93. http://dx.doi.org/10.4028/www.scientific.net/amr.93-94.190.

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This work presents a micromechanics-based model to investigate the effective thermo-electric properties of piezoelectric composite materials. The effective thermo-electric properties are derived by considering a multi-coated ellipsoidal inhomogeneity embedded in a host material in the framework of the generalized self-consistent method (GSCM). An incremental scheme, in which the reinforcements are incrementally put in the host material, is implemented. The validation of the micromechanical model is performed with experimental data. The model proposed has a wide range of applications and can be extended to other physical properties.

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Huang, Zheng-Ming. "On micromechanics approach to stiffness and strength of unidirectional composites." Journal of Reinforced Plastics and Composites 38, no. 4 (2018): 167–96. http://dx.doi.org/10.1177/0731684418811938.

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The purposes of this paper are sixfold. First, any micromechanics model for predicting elastic property (stiffness) of a composite is applicable to a reasonable prediction of a composite strength, provided that the homogenized internal stresses in the matrix are converted into true values. The conversion for all of the stress components free of biaxially transverse loads is presented in the paper. Second, the predictability of 12 well-known micromechanics models for stiffness and strength of a unidirectional composite is assessed against the measured data of all of the nine unidirectional composites used in three world-wide failure exercises. An accuracy ranking is made accordingly. Third, it is demonstrated that the smallest fiber volume in a representative volume element for a finite element approach plays a more dominant role than other issues such as a random fiber array to achieve the highest simulation accuracy. This feature has been largely ignored in the current literature. Fourth, a consistency of a micromechanics model in calculating the internal stresses in the fiber and matrix of the composite is an issue that should be taken into account. Among the 12 models considered, only Bridging Model is consistent. A non-consistency implies that a full three-dimensional approach should be used to predict an effective property of the composite even though it is subjected to a uniaxial load. Fifth, an effective method to detect an interface debonding between the fiber and matrix subjected to an arbitrary load is presented in the paper. Only a transverse tensile strength of the composite, in addition to the original fiber and matrix properties, is needed. Whereas essentially any load can cause the interface to debond earlier before a composite failure, only a transverse tensile load carrying capacity of the composite is influenced significantly by the debonding. Specifically, an interface debonding has insignificant effect on a shear strength of the composite. Sixth, a fiber misalignment-induced kink band failure is analyzed by virtue of the original fiber and matrix properties, and a longitudinal compressive strength is predicted micromechanically.

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Serra-Parareda, Ferran, Fabiola Vilaseca, Francesc X. Espinach, Pere Mutjé, Marc Delgado-Aguilar, and Quim Tarrés. "Stiffening Potential of Lignocellulosic Fibers in Fully Biobased Composites: The Case of Abaca Strands, Spruce TMP Fibers, Recycled Fibers from ONP, and Barley TMP Fibers." Polymers 13, no. 4 (2021): 619. http://dx.doi.org/10.3390/polym13040619.

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Biocomposites are composite materials where at least the matrix or the reinforcement phases are obtained from natural and renewable resources. Natural fibers for composite preparation can be obtained from annual plants, wood, recycled products, or agroforestry waste. The present work selected abaca strands, spruce fibers, recycled fibers from old newspaper, and barley fibers as raw materials to produce biocomposites, in combination with a biobased polyethylene. One very important feature in material science and for industrial applications is knowing how a material will deform under load, and this characteristic is represented by Young’s modulus. Therefore, in this work, the stiffness and deformation of the biocomposites were determined and evaluated using macromechanics and micromechanics analyses. Results were compared to those of conventional synthetic composites reinforced with glass fibers. From the micromechanics analysis, the intrinsic Young modulus of the reinforcements was obtained, as well as other micromechanics parameters such as the modulus efficiency and the length and orientation factors. Abaca strands accounted for the highest intrinsic modulus. One interesting outcome was that recycled fibers exhibited similar Young’s moduli to wood fibers. Finally, agroforestry waste demonstrated the lowest stiffening potential. The study explores the opportunity of using different natural fibers when specific properties or applications are desired.

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Qin, Huan Chao, and Ju Lin Wang. "Study on the Constitutive Model of Composite Materials in Elastic-Plastic Stage." Applied Mechanics and Materials 166-169 (May 2012): 73–77. http://dx.doi.org/10.4028/www.scientific.net/amm.166-169.73.

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Elastic-plastic properties of composite materials are an important part of the study on micromechanics. Based on the plastic strain of matrix, the elastic-plastic constitutive model of composite materials is presented in this paper, while considering the influence of the transient flexibility matrix on the flexibility matrix. In comparison with the experimental results, theoretical analysis of the presented model is validated.

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Serra-Parareda, Ferran, Quim Tarrés, Marc Delgado-Aguilar, Francesc X. Espinach, Pere Mutjé, and Fabiola Vilaseca. "Biobased Composites from Biobased-Polyethylene and Barley Thermomechanical Fibers: Micromechanics of Composites." Materials 12, no. 24 (2019): 4182. http://dx.doi.org/10.3390/ma12244182.

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The cultivation of cereals like rye, barley, oats, or wheat generates large quantities of agroforestry residues, which reaches values of around 2066 million metric tons/year. Barley straw alone represents 53%. In this work, barley straw is recommended for the production of composite materials in order to add value to this agricultural waste. First of all, thermomechanical (TMP) fibers from barley straw are produced and later used to reinforce bio-polyethylene (BioPE) matrix. TMP barley fibers were chemically and morphologically characterized. Later, composites with optimal amounts of coupling agent and fiber content ranging from 15 to 45 wt % were prepared. The mechanical results showed the strengthening and stiffening capacity of the TMP barley fibers. Finally, a micromechanical analysis is applied to evaluate the quality of the interface and to distinguish how the interface and the fiber morphology contributes to the final properties of these composite materials.

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Serra, Albert, Ferran Serra-Parareda, Fabiola Vilaseca, Marc Delgado-Aguilar, Francesc X. Espinach, and Quim Tarrés. "Exploring the Potential of Cotton Industry Byproducts in the Plastic Composite Sector: Macro and Micromechanics Study of the Flexural Modulus." Materials 14, no. 17 (2021): 4787. http://dx.doi.org/10.3390/ma14174787.

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The textile sector produces yearly great quantities of cotton byproducts, and the major part is either incinerated or landfilled, resulting in serious environmental risks. The use of such byproducts in the composite sector presents an attractive opportunity to valorize the residue, reduce its environmental impact, and decrease the pressure on natural and synthetic resources. In this work, composite materials based on polypropylene and dyed cotton byproducts from the textile industry were manufactured. The competitiveness of the resulting composites was evaluated from the analyses, at macro and micro scales, of the flexural modulus. It was observed that the presence of dyes in cotton fibers, also a byproduct from the production of denim items, notably favored the dispersion of the phases in comparison with other cellulose-rich fibers. Further, the presence of a coupling agent, in this case, maleic anhydride grafted polypropylene, enhanced the interfacial adhesion of the composite. As a result, the flexural modulus of the composite at 50 wt.% of cotton fibers enhanced by 272% the modulus of the matrix. From the micromechanics analysis, using the Hirsch model, the intrinsic flexural modulus of cotton fibers was set at 20.9 GPa. Other relevant micromechanics factors were studied to evaluate the contribution and efficiency of the fibers to the flexural modulus of the composite. Overall, the work sheds light on the potential of cotton industry byproducts to contribute to a circular economy.

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Abrate, S. "The Mechanics of Short Fiber-Reinforced Composites: A Review." Rubber Chemistry and Technology 59, no. 3 (1986): 384–404. http://dx.doi.org/10.5254/1.3538207.

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Abstract Proper constitutive equations and transformation laws to describe short-fiber-reinforced composites have been reviewed. The mechanisms of load transfer between matrix and fibers have been presented. Micromechanics analyses were discussed in order to predict mechanical properties of the composite given those of the constituents. Such approaches have been used successfully for cord-rubber and particulate-filled elastomeric composites. The use of such methods for short-fiber reinforcement has been limited so far. The problem is more complex in this case, but the need for a reliable method is even stronger in order to evaluate the influence of a parameter change on the various mechanical properties. Elastomeric composites pose a greater change due to the large ratio of fiber-to-matrix moduli, and predictions may not always be accurate. However, the interest of micromechanics approaches is that they allow determination of the effect of a perturbation in the parameters about a given level. Areas for future work include the development of micromechanics methods to determine viscoelastic constants and strength under various loading conditions. The development of a multiaxial strength criterion is needed, and basic fatigue failure mechanisms have to be studied.

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Mooney, R. G., C. A. Costales, E. G. Freeman, et al. "Indentation micromechanics of three-dimensional fibrin/collagen biomaterial scaffolds." Journal of Materials Research 21, no. 8 (2006): 2023–34. http://dx.doi.org/10.1557/jmr.2006.0258.

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The underlying relationships between the microstructure and time-dependent mechanical properties of hydrated fibrin, collagen, and fibrin/collagen composite materials have been explored using an adaptation of the classical rigid, cylindrical, flat punch loaded normally to a planar specimen surface. A suite of quasi-static elastic and viscoelastic indentation experiments have been conducted with uniformly mixed fibrin, collagen, and fibrin/collagen composites, in addition to macrolayered collagen materials. Coupled with insights obtained from optical and confocal fluorescence microscopy, a simple micromechanics model has been developed for the effect of local microstructural variables on the macroscopic mechanical stiffness. These results demonstrate the efficacy of this technique to efficiently and reproducibly probe hydrated engineered tissue replacement materials for local variations in viscoelastic material behavior without the need for extensive specimen preparation or grips, as well as being suitable for performing directly comparable measurements with explants of human skin.

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Yan, Zhi-guo, Yao Zhang, J. Woody Ju, Qing Chen, and He-hua Zhu. "An equivalent elastoplastic damage model based on micromechanics for hybrid fiber-reinforced composites under uniaxial tension." International Journal of Damage Mechanics 28, no. 1 (2017): 79–117. http://dx.doi.org/10.1177/1056789517744425.

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A micromechanics-based equivalent elastoplastic damage model for both notch-sensitive and multiple cracking hybrid fiber reinforced composite is proposed in this study. In this model, the elastic modulus, first cracking strength, and ultimate strength are estimated based on micromechanics. To quantify strain after matrix cracks, a novel characteristic length is defined based on the damage mechanics. The effects of the fiber length, diameter and modulus, and interfacial bond stress on the characteristic length of hybrid fiber reinforced composite are presented. In order to avoid the difficulty of determining the traditional damage and plastic potential function, this model is developed from the behavior of single fiber at mesolevel to the response of hybrid fiber reinforced composite at macrolevel. Then the calculated results are verified with several published experimental results of fiber reinforced composites and hybrid fiber reinforced composite, including notch-sensitive cracking fiber reinforced composite, multiple cracking fiber reinforced composite, and multiple cracking hybrid fiber reinforced composite reinforced with two types of fibers (steel fiber and polyethylene fiber). A parametric study has been performed to investigate the effects of the fiber properties, including the fiber volume fraction, length, diameter, and interfacial bond stress, on the tensile performance of hybrid fiber reinforced composite reinforced with steel fiber-like and polyethylene fiber-like fibers. The results indicate that enhancement of the tensile performance can be achieved more effectively by improving the polyethylene fiber-like fiber than steel fiber-like fiber.

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Tang, Tian, and Wenbin Yu. "A variational asymptotic micromechanics model for predicting conductivities of composite materials." Journal of Mechanics of Materials and Structures 2, no. 9 (2007): 1813–30. http://dx.doi.org/10.2140/jomms.2007.2.1813.

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Buryachenko, V. A. "Locality Principle and General Integral Equations of Micromechanics of Composite Materials." Mathematics and Mechanics of Solids 6, no. 3 (2001): 299–321. http://dx.doi.org/10.1177/108128650100600306.

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Azoti, W. L., Y. Koutsawa, A. Tchalla, A. Makradi, and S. Belouettar. "Micromechanics-based multi-site modeling of elastoplastic behavior of composite materials." International Journal of Solids and Structures 59 (May 2015): 198–207. http://dx.doi.org/10.1016/j.ijsolstr.2015.02.002.

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Sepahvand, Kian K. "Deep Learning Based Uncertainty Analysis in Computational Micromechanics of Composite Materials." Applied Mechanics 2, no. 3 (2021): 559–70. http://dx.doi.org/10.3390/applmech2030031.

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Design of new materials is quite a difficult task owing to various time and length scales and affiliated uncertainties. The major challenge is to include all these in a conventional model. Hyperparameter models in machine learning can be used to overcome these issues. In this paper, an artificial neural network (ANN) model is developed to estimate the effective elastic parameters of unidirectional fiber reinforced composites using representative volume elements (RVE) considering uncertainty in the fiber diameter. The diameter probability distribution is constructed from the acquired gray images by employing image processing operations. The generalized Polynomial Chaos (gPC) expansion is then used to represent the distribution as a random input parameter for finite element analysis, from where the effective parameters are realized. Similarly, the outputs of the FE model, i.e., elastic parameters, are approximated by gPC expansions having unknown deterministic coefficients and random orthogonal Hermite polynomials. A set of collocation points are generated from roots of the random polynomials; from there, the unknown coefficients are estimated. The realization samples are utilized to train an ANN algorithm based on supervised deep learning. The developed ANN model is later tested and validated for a new sample set of data. It is shown that the ANN model with few hidden layers and neurons has a high accuracy for estimation of the elastic parameters directly from the information on the distribution of fiber diameters.

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Urbahs, Alexander, Mukharbiy Banov, Vladislav Turko, and Kristine Tsaryova. "The Characteristic Features of Composite Materials Specimen’s Static Fracture Investigated by the Acoustic Emission Method." Applied Mechanics and Materials 232 (November 2012): 28–32. http://dx.doi.org/10.4028/www.scientific.net/amm.232.28.

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The work is dedicated to the experimental study of micromechanics process of unidirectional composite materials’ specimens under static loading till its fracture using acoustic emission method compared with the strain-load deformation curve. An attempt is made to identify subtle effects of the failure process of the composite material which is impossible using the traditional methods of the strain measurement. The prospect of applying the method of acoustic emission (AE) for the development and improvement of existing methods of model tense- analysis is shown. The characteristic stages of the damage accumulation for unidirectional composites’ specimens and the effect of training on these processes are shown experimentally. It’s shown that the AE-deformation diagram have three stages in contrast to commonly used load-strain deformation curve with one stage. So it become possible to investigate the physical process of composite unit’s fracture under static load.

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Roy, A. K., and S. W. Tsai. "Design of Thick Composite Cylinders." Journal of Pressure Vessel Technology 110, no. 3 (1988): 255–62. http://dx.doi.org/10.1115/1.3265597.

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A simple and efficient design method for thick composite cylinders is presented. Micromechanics and macromechanics are integrated by simple relations and the integrated micro and macromechanics approach has been adopted to enable the designers to instantly study the sensitivity of the micromechanical variables on the final design. The stress analysis is based on 3-dimensional elasticity by considering the cylinder in the state of generalized plane strain. The analysis for both open-ended (pipes) and closed-ended (pressure vessels) cylinders subjected to internal and external pressures and axial load is presented. The failure of the cylinders is predicted by using a 3-dimensional quadratic failure criterion. A degradation model is used to calculate burst pressures and the calculated burst pressures agree very well with the available experimental results, for both thin and thick cylinders. In optimizing multilayer cylinders, the 3-D quadratic criterion enables one to obtain the optimal layer sequence very easily. It is found that the layer sequence is very critical in optimizing, in particular, thick cylinders. In addition, the design parameters and material use efficiency of multilayer closed cylinders subjected to internal pressure have also been studied.

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Lai, Jin Xing, and Qian Zhang. "Analytical Method to Equivalent Modulus of Entrainment Multiphase Composite." Applied Mechanics and Materials 52-54 (March 2011): 1757–61. http://dx.doi.org/10.4028/www.scientific.net/amm.52-54.1757.

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Energy equivalent modulus medium of entrainment multiphase composite body is one of main methods, Those methods study frangible materials damage in micromechanics. Through studying the physical and mechanical process of microstructure varity, we can introduce some kind averaging method to find the material’s macroscopic property. It has not been studied as yet that we study entrainment composite body’s damage trough introducing continous field variable of every exponent tensor from macrophenomenology angle. This paper regards entrainment multiphase composite body as the micropolar medium of introducing inner structure. It provides analytic formula to describe equivalent modus of entrainment multiphase composite body damage, through the stress in micropolar theory of elasticity,couple-stresses tensor and Helmhoetz degrees of freedom density.

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Dvorak, George J. "ASME 1992 Nadai Lecture—Micromechanics of Inelastic Composite Materials: Theory and Experiment." Journal of Engineering Materials and Technology 115, no. 4 (1993): 327–38. http://dx.doi.org/10.1115/1.2904226.

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Some recent theoretical and experimental results on modeling of the inelastic behavior of composite materials are reviewed. The transformation field analysis method (G. J. Dvorak, Proc. R. Soc. London, Series A437, 1992, pp. 311–327) is a general procedure for evaluation of local fields and overall response in representative volumes of multiphase materials subjected to external thermomechanical loads and transformations in the phases. Applications are presented for systems with elastic-plastic and viscoelastic constituents. The Kroner-Budiansky-Wu and the Hill self-consistent models are corrected to conform with the generalized Levin formula. Recent experimental measurements of yield surfaces and plastic strains on thin-walled boron-aluminum composite tubes are interpreted with several micromechanical models. The comparisons show that unit cell models can provide reasonably accurate predictions of the observed plastic strains, while models relying on normality of the plastic strain increment vector to a single overall yield surface may not capture the essential features of the inelastic deformation process.

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Journal articles on the topic 'Micromechanics. Composite materials'

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