Content uploaded by Waleed Ahmed
Author content
All content in this area was uploaded by Waleed Ahmed on Apr 01, 2014
Content may be subject to copyright.
A preview of the PDF is not available
2D VS. 3D INVESTIGATION OF FRACTURED PARTICULATE REINFORCED COMPOSITES
Abstract
Two dimensional finite element model is used to predict the stiffness of particulate reinforce composites through ANSYS software, where linear elastic behavior is adopted. Mainly the investigation covers the analysis of two main cases, the perfect reinforcement, where the particles reinforcement are considered as fully intact, whereas in the second case the particles are fully fractured. The particle’s stiffness is considered as a parameter in the analysis. Moreover, various particle volume fractions are considered to explore their influence on the effective Young’s modulus for the cases studied. The results are compared with previous 3D results for particulate composites.
ResearchGate has not been able to resolve any citations for this publication.
This work investigates the influence of the interfacial debonding in a nanofiber reinforced composite on the mechanical properties. Mainly, three dimensional-axisymmetric finite element analysis is adopted to study a representative volume element (RVE) which is consist of carbon nanofiber confined by a polymeric matrix and subjected to axial tension. Besides, a longitudinal interfacial debonding is imposed along the interfacial nanofiber/matrix. The result of the FEA demonstrate a significant impact of the interfacial debonding on the Young's modulus of the nanocomposite.
The objective of this study is to investigate numerically using FEM the interfacial stresses and defects between the nanofibre and the matrix of nanocomposite. Because of complexity of the problem, 2D finite element analysis is carried out to simulate the cracked nanofibre composite, and 8-node quadrilateral element is utilized in the investigation. ANSYS software is used to explore Stress Intensity Factor (SIF) and the interfacial stresses of the matrix/nanofibre interface. The interfacial defect is simulated as a sharp crack to predict the SIF at the defect tip. The level of the local interfacial stresses arises at the defected spot is inspected as well. The defected nanocomposite is studied under simulated static loading conditions for both uniaxial and biaxial tensile stress. In addition, the defect size and the modulus of elasticity of various types of nanofibre are considered as parameters in the work. Consequently, it is shown that the interfacial stresses increase as the defect length increases. Furthermore, the stress level approaches fourteen times the applied stresses as the defect length come close to the fibre length. Whereas it is observed that the nanofibre restrain the SIF, but insignificant percentage of reduction in SIF is observed due to increase nanofibre modulus of elasticity. © 2006-2011 Journal of Nanostructured Polymers and Nanocomposites.
Studying the influence of a nanoinclusion embedded in nanofiber reinforced composite alongside a nanofiber is the objective of the present investigation. The analysis is done based on 2D, linear elastic finite element through using finite element package ANSYS/Mechanical to explore the impact of the nanoinclusion on the mechanical behavior of the nanocomposite. Mainly, two scenarios are the major outlines of the study, first whenever the presence of the nanoinclusion is located at the longitudinal side of the nanofiber, whereas in the second case, the nanoinclusion is proposed to be along the transverse side of the nanofiber. The levels of the interfacial stresses, normal and shear along the nanofiber’s sides are estimated and discussed. The mechanical properties of the matrix and the nanofiber of the nanocomposite are considered be similar to the traditional well known materials, while for the modeling purposes of the stiffness of the nanoinclusion, is taken as 1/100 of the matrix stiffness. The nanocomposite is subjected to uniaxial tensile stress which is the main stress applied. The implications of the existence of the nanoinclusion on the failure of the nanocomposite due to increases of the interfacial stresses in the nanofiber/matrix line are discussed as well. It is shown through the analysis that the nanoinclusion has a great influence on the increase of the interfacial stresses along the sides of the nanofiber in a nanocomposite in different level and conditions according to the location of the nanoinclusion, and this essentially is considered as one of the main reasons of the anticipated nanocomposite failure.
In this paper the effect of the squeeze casting parameters on the mechanical properties of Al/SiC p composites fabricated by squeeze casting technique is discussed. The SiC particles are well distributed in the liquid Al matrix by mechanical stirring and the melt is then subjected to squeeze pressure. The squeeze pressure ranges from 0 to 130 MPa while the melt and die temperatures are maintained 800 °C and 400 °C respectively. The SiC particles distribution in the Al matrix was studied by microstructure analysis, hardness distribution and density distribution. The tensile and impact tests were performed to study the effect of squeeze pressure on the properties. The results reveal that the Al/SiC p composite produced by applying large squeeze pressure of about 100 MPa has superior mechanical properties.
In this paper the double-inclusion model, originally developed to determine effective linear elastic properties of composite materials, is reformulated and extended to predict the effective nonlinear elastic–plastic response of two-phase particulate composites reinforced with spherical particles. The resulting problem of elastic–plastic deformation of a double-inclusion embedded in an infinite reference medium subjected to an incrementally applied far-field strain is solved by the finite element method. The proposed double-inclusion model is evaluated by comparison of the model predictions to the available exact results obtained by the direct approach using representative volume elements containing many particles. It is found that the double-inclusion formulation is capable of providing accurate prediction of the effective elastic–plastic response of two-phase particulate composites at moderate particle volume fractions.
Based on the incremental damage theory, the influences of particle-cracking damage and its residue strengthening capacity on the stress–strain response of particle reinforced (metal matrix composite) MMC under uniaxial tension are carefully investigated in this paper. Two kinds of models are adopted in the numerical calculation to predict the damage evolution of MMC, one is modeling the broken particles as voids and the other is considering the remaining load carrying capacity of the damaged particles. Special emphasis is placed on the detailed comparison between the results predicted by the two models under different parameters such as the aspect ratio, volume fraction of particle and the elastic–plasticity properties of matrix. The damage process of MMC and the development of stress in the particles are predicted by two models and carefully analyzed.
3D Finite element calculations comparing to axisymmetric calculations have been performed to predict quantitatively the tensile behaviour of composites reinforced with ceramic particles aligned in stripes. The analyses are based on a unit cell model, which assumes the periodic arrangement of reinforcements. The results are presented in such a manner that can be directly compared for all possible aspect ratios and inclusion volume fractions. It is indicated that varying the distance between the stripes when particle volume fraction is kept constant significantly influences the overall mechanical behaviour of composites. Whereas during elastic deformation 3D and axisymmetric formulations predict quantitatively similar results, the mechanical behaviour perpendicular to the stripe direction predicted by 3D and axisymmetric models may differ depending on the inclusion volume fraction. Nevertheless an appreciable strengthening in the stripe direction independent on the model and deformation stage is predicted.
This paper considers the problem of prediction of the effective Young’s modulus of a particulate composite material containing fractured particles. It treats the general case in which some particles are fractured while others remain intact. The reinforcing particles are assumed to be spherical. The Mori–Tanaka model is extended to formulate the method of solution. The resulting auxiliary problem of a single fractured particle in an infinite matrix subjected to a remote stress equal to the average matrix stress, for which Eshelby’s solution does not exist, is solved by the finite element method. The predictions are compared with the exact results of Young’s modulus for particulate composites with body-centered cubic packing arrangement and experimental results of Young’s modulus for particulate composites containing fractured particles.
This review discusses some recent advances in polymer silicate nanocomposites. In particular, we highlight the properties of specific nanocomposites while emphasizing the lack of properties trade-offs in these systems. We also present our work on the structure and dynamics of the polymer/nanofiller interface and attempt to relate them to macroscopic nanocomposite properties.
In the modeling of microstructural damage mechanisms of composites, damage evolution plays an important role and has significant effects on the overall nonlinear behavior of composites. In this study, a microstructural Monte Carlo simulation method is proposed. to predict the volume fraction evolution of damaged particles due to particle-cracking for metal matrix composites with randomly distributed spheroidal particles. The performance function is constructed using a stress-based damage criterion. A micromechanics-based elastoplastic and damage model is applied to compute the local stress field and to estimate the overall nonlinear response of the composites with particle-cracking damage, mechanism. The factors that affect the damage evolution are investigated and the effects of particle shape and damage strength on damage evolution are discussed in detail. Simulation results are compared with experiments and good agreement is obtained.