Plasticity of Particle-Reinforced Composites With a Ductile Interphase

1998 ◽  
Vol 65 (3) ◽  
pp. 596-604 ◽  
Author(s):  
K. Ding ◽  
G. J. Weng
Keyword(s):  
Composite System ◽  
Homogenization Theory ◽  
Two Phase ◽  
Elastoplastic Behavior ◽  
Reinforced Composite ◽  
Three Phase ◽  
The Matrix ◽  
Fluctuation Method ◽  
Ductile Interphase ◽  
Particle Reinforced Composite

A homogenization theory is developed to determine the overall elastoplastic behavior of a particle-reinforced composite with a ductile interphase. Unlike most existing homogenization theories which are primarily concerned with the ordinary two-phase composites, the present one is confronted with two ductile phases, with one enclosing the other. The theory is developed with the aid of a linear comparison composite using a field-fluctuation method to calculate an energy-based effective stress of the ductile phases. In order to examine its accuracy, an exact elastic-plastic analysis under dilatational loading is also developed, and it was found that, despite its simplicity, the theory could provide plausible estimates for the overall behavior of the three-phase composite. The theory is applicable to a composite system regardless whether the interphase is more ductile or stiffer than the matrix, and when the interphase is more ductile, it is shown that even the presence of a thin layer can have a very significant effect on the plasticity of the overall composite.

The Influence of a Ductile Interphase on the Overall Elastoplastic Behavior of a Fiber-Reinforced Composite

1999 ◽  
Vol 66 (1) ◽  
pp. 21-31 ◽  
Author(s):  
K. Ding ◽  
G. J. Weng
Keyword(s):  
Biaxial Loading ◽  
Homogenization Theory ◽  
Fiber Reinforced ◽  
Elastoplastic Behavior ◽  
Fiber Reinforced Composite ◽  
Axial Tension ◽  
Reinforced Composite ◽  
Axial Tensile ◽  
The Matrix ◽  
Ductile Interphase

While there exist various homogenization theories for the plasticity of a fiber-reinforced composite, no such theories have been explicitly developed to account for the influence of a ductile interphase. In this paper a simple scheme is developed for such a purpose. The theory evolved out of the work of Qiu and Weng (1992) and Hu (1996), and bears an identical structure to Ponte Castan˜eda’s (1991) variational procedure and Suquet’s (1995, 1996) modified secant moduli approach. An exact solution under the plane-strain biaxial loading is also developed to assess the accuracy of the theory. It is found that, with either a soft or a hard interphase and with or without work-hardening, the homogenization theory can produce sufficiently accurate results under this condition. The theory is then used to examine the influence of the interphase volume concentration on the anisotropic behavior of the composite under axial tension, transverse tension, axial shear, and transverse shear, with both a soft and a hard interphase. The results indicate that, while the axial tensile behavior is not sensitive to the interphase concentration, the behaviors under other types of loading are greatly affected by its presence, especially when the interphase is softer than the matrix.

Three Phase Micromechanical Modeling for a Shape Memory Alloy Reinforced Composite

2006 ◽  
Vol 324-325 ◽  
pp. 939-942 ◽  
Author(s):  
Yu Ping Zhu ◽  
Guan Suo Dui
Keyword(s):  
Transformation Strain ◽  
Micromechanical Modeling ◽  
Phase Method ◽  
Free Energy Function ◽  
Fiber Volume ◽  
Two Phase ◽  
Austenitic Phase ◽  
Three Phase ◽  
The Matrix ◽  
Three Phases

In this paper, combined the micromechanical and the thermodynamic theory, a three phase model for the SMA composite is developed, in which the composite is considered as the austenitic phase, the product phase (martensite) and the matrix phase. In the present model, the interaction among the three phases is analyzed. From the micromechanical analysis, the macroscopic free energy function is found. Then macroscopic transformation strain, effective elastic compliance, macroscopic constitutive model are derived.Compared with the traditional two-phase method, non-linearity of SMA need not be considered. The method is not only simply but also the interaction among the three phases is considered. As an application of above model, we consider the case of a composite with NiTi/epoxy, illustrate the predicted stress-strain response of it under isothermal loading and unloading conditions and analyses the effects of temperature and fiber volume on macroscopic mechanical property. By comparing with references, it is shown that the results are credible. It is helpful to design the intelligent composite.

The Effect of Initial Void on the Elasto-Plastic Properties of Particle-Reinforced Composite Coating

2012 ◽  
Vol 161 ◽  
pp. 281-285
Author(s):  
Sheng Ting Gu ◽  
Yu Mei Bao ◽  
Guo Zhong Chai
Keyword(s):  
Composite Coating ◽  
Microscopic Theory ◽  
Spherical Particles ◽  
Plastic Properties ◽  
Reinforced Composite ◽  
Micro Cracks ◽  
Particle Damage ◽  
The Matrix ◽  
Damage Process ◽  
Particle Reinforced Composite

Many defects such as micro-voids, micro-cracks are introduced during the preparation of particle reinforced composite coating, which significantly change the mechanical properties of the coating. Based on Mori-Tanaka’s concept of average stress in the matrix and Eshelby’s equivalent inclusions microscopic theory, an incremental theory coupled with ABAQUS subroutine UMAT, is developed to study the influence of initial void and void growth on elasto-plastic properties of composite coating. In the composite containing hard spherical particles, debonding of particle-matrix interface is a significant damage process, and the effect of initial void on particle damage is also considered.

Effective Transverse Elastic Properties of Composites Containing Two Types of Continuous Fibers

2007 ◽  
Vol 23 (4) ◽  
pp. 309-318
Author(s):  
P. J. Lin
Keyword(s):  
Elastic Properties ◽  
Current Approach ◽  
Two Phase ◽  
Reinforced Composite ◽  
Proposed Model ◽  
Three Phase ◽  
Local Solutions ◽  
Rigid Fibers ◽  
Interaction Problem ◽  
Properties Of Composites

AbstractBased the previously published model on the two-dimensional micromechanical fiber interaction framework of two-phase composites, effective transverse elastic properties of composites containing two types of randomly located yet unidirectionally aligned circular fibers are studied in this paper. Approximate local solutions for the interaction problem of two randomly located circular fibers of different elastic properties are presented. A fiber-reinforced composite material containing two extreme types of inclusions, voids and rigid fibers, is also investigated. Comparison with Hashin's variational bounds and Mori-Tanaka method, the current approach provides reasonably accurate predictions for three-phase composites. Finally, numerical simulation examples are implemented to demonstrate the capability of the proposed model.

Modeling steady wear of steel/Al2O3Al particle reinforced composite system

Wear ◽  
1997 ◽  
Vol 211 (2) ◽  
pp. 147-150 ◽  
Author(s):  
Zhenfang Zhang ◽  
Liangchi Zhang ◽  
Yiu-Wing Mai
Keyword(s):  
Composite System ◽  
Reinforced Composite ◽  
Particle Reinforced Composite

scholarly journals A Numerical Method for Analysing Heat Conduction in Composites Containing Encapsulated Phase Change Materials

2018 ◽  
Vol 237 ◽  
pp. 02012
Author(s):  
Hui Wang ◽  
Qing-Hua Qin
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Composite System ◽  
Matrix Material ◽  
Heat Transfer Model ◽  
Transient Heat Transfer ◽  
Cement Matrix ◽  
Transfer Model ◽  
Two Phase ◽  
Three Phase

In this study, a three-dimensional transient heat transfer model in a three-phase composite system is established to investigate effects of temperature reduction in a composite system due to the use of encapsulated phase change material (PCM). The entire composite system is composed of cement matrix material, PCM, and hollow metal microspheres (HMSs) which are introduced to accelerate the phase change efficiency of the PCM and to simultaneously hold the liquid phase of the PCM. The present transient heat transfer model is numerically solved via finite element technique for investigating the transient thermal performance of the three-phase composite system. The temperature distribution on the specific area is compared to that in the pure cement material and the two-phase composite system without metal shell for demonstrating the ability of temperature adjustment of the PCM. Finally, effects of the spatial distribution of HMS on the temperature variation in the three-phase composite system is further investigated to provide comprehensive understanding on energy adjustment of this composite system.

scholarly journals Study on the Relationships between Microscopic Cross-Linked Network Structure and Properties of Cyanate Ester Self-Reinforced Composites

Polymers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 950
Author(s):  
Hongtao Cao ◽  
Beijun Liu ◽  
Yiwen Ye ◽  
Yunfang Liu ◽  
Peng Li
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
The Self ◽  
Reinforced Composites ◽  
Two Phase ◽  
Reinforced Composite ◽  
Transmission Electron ◽  
The Matrix ◽  
Ft Ir ◽  
The Cross

Bisphenol A dicyanate (BADCy) resin microparticles were prepared by precipitation polymerization synthesis and were homogeneously dispersed in a BADCy prepolymer matrix to prepare a BADCy self-reinforced composites. The active functional groups of the BADCy resin microparticles were characterized by Fourier transform infrared (FT-IR) spectroscopy. The results of an FT-IR curve showed that the BADCy resin microparticles had a triazine ring functional group and also had an active reactive group -OCN, which can initiate a reaction with the matrix. The structure of the BADCy resin microparticles was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). From the TEM results, the BADCy resin microparticles dispersed in the solvent were nano-sized and distributed at 40–60 nm. However, from the SEM results, agglomeration occurred after drying, the BADCy resin particels were micron-sized and distributed between 0.3 μm and 0.6 μm. The BADCy resin prepolymer was synthesized in our laboratory. A BADCy self-reinforced composite was prepared by using BADCy resin microparticles as a reinforcement phase. This corresponds to a composite in which the matrix and reinforcement phase are made from different morphologies of the same monomer. The DSC curve showed that the heat flow of the microparticles is different from the matrix during the curing reaction, this means the cured materials should be a microscopic two-phase structure. The added BADCy resin microparticles as reaction sites induced the formation of a more complete and regular cured polymer structure, optimizing the cross-linked network as well as increasing the interplay between the BADCy resin microparticles and prepolymer matrix. Relative to the neat BADCy resin material, the tensile strength, flexural strength, compressive strength and impact strength increased by 98.1%, 40.2%, 27.4%, and 85.4%, respectively. A particle toughening mechanism can be used to explain the improvement of toughness. The reduction in the dielectric constant showed that the cross-linked network of the self-reinforced composite was more symmetrical and less polar than the neat resin material, which supports the enhanced mechanical properties of the self-reinforced composite. In addition, the thermal behavior of the self-reinforced composite was characterized by thermogravimetric analysis (TGA) and dynamic mechanical thermal analysis (DMTA). The results of DMTA also establishes a basis for enhancing mechanical properties of the self-reinforced composite.

Transition alpha structure in beta-isomorphous Nb-Hf alloys

1987 ◽  
Vol 45 ◽  
pp. 232-233
Author(s):  
R.W. Carpenter ◽  
Changhai Li ◽  
David J. Smith
Keyword(s):  
Solid Solution ◽  
Solution Phase ◽  
Miscibility Gap ◽  
Large Strains ◽  
Solid Solution Phase ◽  
Two Phase ◽  
Diffuse Intensity ◽  
Metastable Form ◽  
The Matrix ◽  
Equilibrium Morphology

Binary Nb-Hf alloys exhibit a wide bcc solid solution phase field at temperatures above the Hfα→ß transition (2023K) and a two phase bcc+hcp field at lower temperatures. The β solvus exhibits a small slope above about 1500K, suggesting the possible existence of a miscibility gap. An earlier investigation showed that two morphological forms of precipitate occur during the bcc→hcp transformation. The equilibrium morphology is rod-type with axes along <113> bcc. The crystallographic habit of the rod precipitate follows the Burgers relations: {110}||{0001}, <112> || <1010>. The earlier metastable form, transition α, occurs as thin discs with {100} habit. The {100} discs induce large strains in the matrix. Selected area diffraction examination of regions ∼2 microns in diameter containing many disc precipitates showed that, a diffuse intensity distribution whose symmetry resembled the distribution of equilibrium α Bragg spots was associated with the disc precipitate.

Using crystallographic symmetry in diffraction and contrast analysis

1989 ◽  
Vol 47 ◽  
pp. 504-505
Author(s):  
U. Dahmen ◽  
K.H. Westmacott
Keyword(s):  
Electron Microscopy ◽  
High Symmetry ◽  
Two Phase ◽  
Tem Analysis ◽  
Crystallographic Symmetry ◽  
The Matrix ◽  
Contrast Analysis ◽  
Practical Tool ◽  
Convergent Beam ◽  
Beam Diffraction

Despite the increased use of convergent beam diffraction, symmetry concepts in their more general form are not commonly applied as a practical tool in electron microscopy. Crystal symmetry provides an abundance of information that can be used to facilitate and improve the TEM analysis of crystalline solids. This paper draws attention to some aspects of symmetry that can be put to practical use in the analysis of structures and morphologies of two-phase materials.It has been shown that the symmetry of the matrix that relates different variants of a precipitate can be used to determine the axis of needle- or lath-shaped precipitates or the habit plane of plate-shaped precipitates. By tilting to a special high symmetry orientation of the matrix and by measuring angles between symmetry-related variants of the precipitate it is possible to find their habit from a single micrograph.

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