Geometrical Anisotropy in Biphase Particle Reinforced Composites

2010 ◽  
Vol 77 (4) ◽  
Author(s):  
Shivakumar I. Ranganathan ◽  
Paolo Decuzzi ◽  
Lewis T. Wheeler ◽  
Mauro Ferrari
Keyword(s):  
Composite Materials ◽  
Elastic Constants ◽  
Crucial Role ◽  
Particle Shape ◽  
Volume Fraction ◽  
Effective Stiffness ◽  
Reinforced Composites ◽  
Effective Elastic Constants ◽  
Anisotropy Index ◽  
Particle Reinforced Composites

Particle shape plays a crucial role in the design of novel reinforced composites. We introduce the notion of a geometrical anisotropy index A to characterize the particle shape and establish its relationship with the effective elastic constants of biphase composite materials. Our analysis identifies three distinct regions of A: (i) By using ovoidal particles with small A, the effective stiffness scales linearly with A for a given volume fraction α; (ii) for intermediate values of A, the use of prolate particles yield better elastic properties; and (iii) for large A, the use of oblate particles result in higher effective stiffness. Interestingly, the transition from (ii) to (iii) occurs at a critical anisotropy Acr and is independent of α.

An Interfacial Debonding Model for Particle-Reinforced Composites

2002 ◽  
Author(s):  
H. T. Liu ◽  
L. Z. Sun ◽  
J. W. Ju
Keyword(s):  
Volume Fraction ◽  
Three Dimensional ◽  
Damage Mechanism ◽  
Interfacial Debonding ◽  
Elastic Behavior ◽  
Reinforced Composites ◽  
Stiffness Tensor ◽  
Particle Reinforced Composites ◽  
Damage Process ◽  
Multi Phase

To simulate the evolution process of interfacial debonding between particle and matrix, and to further estimate its effect on the overall elastic behavior of particle-reinforced composites, a two-level microstructural-effective damaged model is developed. The microstructural damage mechanism is governed by the interfacial debonding of reinforcement and matrix. The progressive damage process is represented by the debonding angles that are dependent on the external loads. For those debonded particles, the elastic equivalency is constructed in terms of the stiffness tensor. Namely, the isotropic yet debonded particles are replaced by the orthotropic perfect particles. The volume fraction evolution of debonded particles is characterized by the Weibull’s statistical approach. Mori-Tanaka’s method is utilized to determine the effective stiffness tensor of the resultant multi-phase composites. The proposed constitutive framework is developed under the general three-dimensional loading condition. Examples are conducted to demonstrate the capability of the proposed model.

Environmentally-Induced Expansion of Heterogeneous Media

1989 ◽  
Vol 56 (3) ◽  
pp. 546-549 ◽  
Author(s):  
Kalman Schulgasser
Keyword(s):  
Composite Materials ◽  
Relative Humidity ◽  
Elastic Constants ◽  
Heterogeneous Media ◽  
Direct Method ◽  
Environmental Variable ◽  
Effective Elastic Constants ◽  
Effective Expansion ◽  
Expansion Behavior

Relationships between effective expansion behavior and effective elastic constants for composite materials have been known for many years. In the present work composites are considered for which more than one environmental variable (e.g., temperature and relative humidity) cause expansions. A simple direct method to relate effective expansions due to different causes is developed. It is shown that most of the previous elasticity-expansion behavior results are gotten as corollaries, and the applicability of these relationships is broadened.

Evaluation of mechanical properties of fiber reinforced composites filled with hollow spheres: A micromechanics approach

2020 ◽  
pp. 002199832094964
Author(s):  
Mojde Biarjemandi ◽  
Ehsan Etemadi ◽  
Mojtaba Lezgy-Nazargah
Keyword(s):  
Mechanical Properties ◽  
Elastic Constants ◽  
Volume Fraction ◽  
Hollow Spheres ◽  
Matrix Phase ◽  
Fiber Reinforced Composites ◽  
Fiber Direction ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
The Matrix

Recent researches show that the embedment of hollow spheres in the matrix phase of composite materials improves the strength of these structures against crack propagations. Rare studies are reported for calculating equivalent elastic constants of fiber reinforced composites containing hollow spheres. In this paper, the effects of hollow spheres on mechanical characteristics of fiber reinforced composite are studied for the first time. To achieve this aim, a micromechanics based finite element method is employed. Representative volume elements (RVEs) including hollow spheres with different radius, thickness and volume fraction of hollow spheres, are modeled by using 3D finite elements. The equivalent elastic constants are calculated through homogenization technique. The results are compared with available experimental works. Good agreements find between two sets of results. Also, the volume fraction, number and thickness of hollow spheres as effective parameters on mechanical properties of composite were investigated. The results show the equivalent elastic properties increase with increasing the volume fraction and number of hollow spheres and decrease with increasing the number of hollow spheres. Furthermore, the equivalent Young’s modulus in transverse directions to the fiber direction and shear modulus of the composite increase with increasing the thickness of hollow spheres. As a final result, the presence of hollow spheres in the matrix phase generally increases the equivalent elastic constants without significant changes in the weight of structures.

Absolute effective elastic constants of composite materials

2016 ◽  
Vol 57 (5) ◽  
pp. 897-920 ◽  
Author(s):  
Osman Bulut ◽  
Necla Kadioglu ◽  
Senol Ataoglu
Keyword(s):  
Composite Materials ◽  
Elastic Constants ◽  
Effective Elastic Constants

Damping Properties of 6063Al/Al2O3 SiO2 Particle Reinforced Composites

2007 ◽  
Vol 546-549 ◽  
pp. 633-637
Author(s):  
Yue Ying Li ◽  
Yong Bing Liu ◽  
Zhan Yi Cao
Keyword(s):  
High Temperature ◽  
Fly Ash ◽  
Internal Friction ◽  
Volume Fraction ◽  
Stir Casting ◽  
Reinforced Composites ◽  
Sio2 Particle ◽  
Particle Reinforced Composites ◽  
Sio2 Particles ◽  
Damping Peak

The stir-casting method was utilized in this paper to synthesize 6063Al/Al2O3·SiO2 reinforced composites consisting of 6063Al alloy as matrix and Al2O3·SiO2 particles as additive with content of 5%, 10%, 15%, 20% (volume fraction) respectively. Al2O3·SiO2 particles were obtained from fly ash particles of Steam Power Plant and were pretreated. The shape of these fly ash particles was spheroidal and ellipsoidal. The damping behavior of 6063Al/Al2O3·SiO2 particle reinforced composites was studied by measuring the composite’s internal friction values on a Multifunctional Damping Measurement Apparatus. Under the condition of this series of experiments, 6063Al/Al2O3·SiO2 particle reinforced composites had a higher internal friction values than that of 6063Al matrix and also showed the dependency of internal friction on Al2O3·SiO2 particles volume fraction, particles dimension, vibration frequency and temperature. There was an increased trend for internal friction values with increasing the volume fraction of Al2O3·SiO2 particles and decreasing particles dimension of Al2O3·SiO2 at the same frequency and the different temperature. It has been found that in the lower frequency, the higher internal friction value was obtained. The internal friction of the composites increased with increasing temperature. In the case of lower frequency, two damping peak were observed. A low-temperature damping peak appeared at a temperature near 245°C which a high-temperature damping peak appeared near 450°C. Based on the experimental results, the damping mechanism of 6063Al/Al2O3·SiO2 particle reinforced composites was preliminary discussed. It may be concluded that the damping mechanisms associated with 6063Al/Al2O3·SiO2 reinforced composites include mainly intrinsic damping, dislocation damping and interface damping. However, only the interface damping mechanism is dominant at high temperature.

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