Elastic modulus and interface stress constraint of particle-reinforced composites (original) (raw)
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Particle shape influence on elastic-plastic behaviour of particle-reinforced composites
Archives of materials science and engineering, 2014
Particle-reinforced composite materials very often provide unique and versatile properties. Modelling and prediction of effective heterogeneous material behaviour is a complex problem. However it is possible to estimate an influence of microstructure properties on effective macro material properties. Mentioned multi-scale approach can lead to better understanding of particle-reinforced composite behaviour. The paper is focused on prediction of an influence of particle shape on effective elastic properties, yield stress and stress distribution in particle-reinforced metal matrix composites. Design/methodology/approach: This research is based on usage of homogenization procedure connected with volume averaging of stress and strain values in RVE (Representative Volume Element). To create the RVE geometry Digimat-FE software is applied. Finite element method is applied to solve boundary value problem, in particular a commercial MSC.Marc software is used. Findings: Cylindrical particles provide the highest stiffness and yield stress while the lowest values of stiffness and yield stress are connected with spherical particles. On the other hand stress distribution in spherical particles is more uniform than in cylindrical and prismatic ones, which are more prone to an occurrence of stress concentration. Research limitations/implications: During this study simple, idealised geometries of the inclusions are considered, in particular sphere, prism and cylinder ones. Moreover, uniform size and uniform spatial distribution of the inclusions are taken into account. However in further work presented methodology can be applied to analysis of RVE that maps the real microstructure. Practical implications: Presented methodology can deal with an analysis of composite material with any inclusion shape. Predicting an effective composite material properties by analysis of material properties at microstructure level leads to better understanding and control of particle-reinforced composite materials behaviour. Originality/value: The paper in details presents in details an investigation of influence of inclusion shape on effective elastic-plastic material properties. In addition it describes the differences between stress distributions in composites with various inclusion shapes.
Prediction of Elastic Parameters of Particle Reinforced Composites Using Finite Element Simulations
Materials Research
The macroscopic properties of composite materials depend on the microscopic properties of the constituents and the geometric arrangement of their phases. Therefore, it is essential to predict heterogeneous materials' mechanical properties by simulating microstructural finite element models. The present article aims to analyze particle reinforced composites composed of spherical alumina inclusions surrounded by a glass matrix using a tridimensional representative volume element. Herein, microstructures are artificially created considering a regular or random arrangement of the inclusions. Two materials systems previously studied in the literature were analyzed. The discretization of the models was performed to have periodic mesh, thus enabling the use of periodic boundary conditions. A finite element model is created using Abaqus software. Numerical results show that the macroscopic properties can be estimated with high accuracy for the temperature where linear matrix behavior stands. The predictions were compared to experimental data from the literature. The models with a regular arrangement of inclusions show a difference inferior to 10%, while random arrangements show a difference inferior to 3.9%. The developed numerical algorithms can be modified to include new features, such as other dispersed phase arrangements or nonlinear material behavior.
Three-dimensional numerical testing of microstructures of particle reinforced composites
Acta Materialia, 2004
Three-dimensional finite element (FE) simulations of the deformation and damage evolution of SiC particle reinforced Al composites are carried out for different microstructures of the composites. A program for the automatic generation and the design of FE meshes for different 3D microstructures of composites is developed. Numerical testing of composites with random, regular, clustered and gradient arrangements of spherical particles is carried out. The fraction of failed particles and the tensile stress–strain curves were determined numerically for each of the microstructures. It was found that the strain hardening coefficient increases with varying the particle arrangement in the following order: gradient < random < clustered < regular microstructure. The variations of the particle sizes causes strong decrease in the strain hardening rate of the composite, and leads to the quicker and earlier damage growth in the composites.
International Journal of Materials Research, 2010
Current technology provides means of fabrication of spherical micro-particles, either hollow or compact, for all sorts of engineering materials. Such spherical particles can be further embedded into another material to build-up either random dispersions or close-packed arrays, according to the production route and the degree of anisotropy intended for the ultimate composite material. In this study, a simple analytical formula for the composite stiffness is derived from an early micromechanics model, to describe the actual reinforcement of ductile matrices by a random dispersion of uniform spherical ceramic particles. Predictions from this model are checked against some other relevant models, and specific features arising from its theoretical derivation are pointed out. The basic model can also predict the stiffness of syntactic composites, whose reinforcements are hollow microsphere dispersions. An application of this new model is demonstrated for the assessment of the ductility of brittle composites reinforced by compact spherical particles.
International Journal of Engineering Science, 2012
A systematic comparison of inhomogeneity shape effects on the linear elastic, thermoelastic and thermal conduction responses of particle reinforced composites is carried out. For this purpose, multi-particle unit cells that contain randomly positioned and, where applicable, oriented, identical particles having the shapes of spheres, regular octahedra, cubes or regular tetrahedra, respectively, and a volume fraction of 20% are employed. The macroscopic moduli and microscopic responses, such as phase averages, as well as phase-level standard deviations and distribution functions of the microfields are evaluated and compared to analytical estimates. The results indicate the presence of relatively small but consistent effects of the particle shape on the effective behavior of particulate composites. Effects on the microscopic stress and flux fields are predicted to be more pronounced.
Computer Methods in Applied Mechanics and Engineering, 2017
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Highlights E lastic properties of particle-reinforced composites containing nonspherical particles of high packing density and interphase: D E M-F E M simulation and micromechanical theory
Metals
Although the porosity in Al-SiC metal matrix composites (MMC) can be diminished; its existence is unavoidable. The purpose of this work is to study the effect of porosity on Young’s modulus of SiC reinforced aluminum matrix composites. Finite element analysis is performed based on the unit cell and the representative volume element approaches. The reliability of the models is validated by comparing the numerical predictions against several experimental data ranging in low- and high-volume fractions and good agreement is found. It is found that despite the stress transfer from the soft matrix to the reinforcement remains effective in the presence of pores, there is a drop in the stress gathering capability of the particles and thus, the resulting effective elastic modulus of composite decreases. The elastic property of the composite is more sensitive to pores away the reinforcement. It is confirmed, qualitatively, that the experimentally reported in the literature decrease in the ela...
Effect of reinforcement geometry on the mechanical properties of composites
Composites Engineering, 1992
The mechanical properties of ceramic composites change due to variations in the size and geometry of the reinforcement. In the present work the effects of Sic whisker (SIC,) and Sic platelets (Sic,) on the mechanical properties of SiC/Al,O, composites have been investigated. The flexural properties of both whisker-and platelet-reinforced SiC/Al,O, composites were measured using the four-point bend test. Fracture toughness was determined for both straight-and chevronnotched specimens. A scanning electron microscopy examination of the fractured surfaces was conducted to perform failure analyses and understand toughening mechanisms. The results of the investigation indicate that SiC,/Al,O, composites provides higher flexural strength and fracture toughness compared to SiC,/Al,Os composites. During hot pressing, the control of the orientation of the Sic, is extremely difficult and it appears to form a porous matrix structure which substantially lowers the strength. Moreover, it has been observed that the low I/d ratio of SIC, has a major influence on the fracture toughness.
Geometrical Method for Determination of Mechanical Properties of Particle Reinforced Composites
2016
Research on microstructure of main engineering materials revealed that some of these materials exhibit similar microstructure patterns at different length scales. Since these patterns are replicated at different length scales the whole microstructure can be viewed as a set of periodic substructures. Homogenization technique for periodic microstructures has found many applications in simulation of composite materials by considering the geometry of fibers distribution. In this study a homogenization technique for periodic microstructures is developed. In this generalization a multi-step homogenization is being used. In each step of homogenization the geometry which is coincident with the true microstructure is produced to maintain the properties of the mechanical properties of the related cell. By using the presented method, effect of size and grading of each of the reinforcing phases and the interaction between fibers is taken into account. The results of the presented theory are compared with the existing experimental data on the particle reinforced composites. Good agreement between the presented theory and experimental data is found.
Computational mesomechanics of particle-reinforced composites
Computational Materials Science, 1999
Numerical models of deformation, damage and fracture in particle-reinforced composite materials, based on the method of multiphase ®nite elements (MPFE) and element elimination technique (EET), are presented in this paper. The applicability of these techniques for dierent materials and dierent levels of simulation was studied. The simulation of damage and crack growth was conducted for several groups of composites: WC/Co hard metal alloys, Al/Si and Al/SiC composites on macro-and mesolevel. It is shown that the used modern techniques of numerical simulation (MPFE and EET) are very ecient in understanding deformation and damage evolution in heterogeneous brittle/ ductile materials with inclusions. Ó : S 0 9 2 7 -0 2 5 6 ( 9 9 ) 0 0 0 5 5 -5