Modeling Strain Localization Using a Plane Stress Two-Particle Model and the Influence of Grain Level Matrix Inhomogeneity

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Xiaohua Hu ◽  
David S. Wilkinson ◽  
Mukesh Jain ◽  
Raja K. Mishra
Keyword(s):  
Plane Stress ◽  
Strain Localization ◽  
Matrix Material ◽  
Interparticle Spacing ◽  
Particle Model ◽  
Element Analysis ◽  
Hard Particles ◽  
The Matrix ◽  
Particle Alignment

The role of dilute small particles on the development of strain localization under uniaxial tension has been studied by finite element analysis using a plane stress model with two small hard particles embedded in Al matrix. The influence of particle alignment and interparticle spacing in a homogeneous and inhomogeneous matrix are investigated. When the matrix material is a homogeneous continuum, there are small localization strains when close packed and aligned along the loading direction. In the case of an inhomogeneous matrix with grains of different strengths represented by their Taylor factors, the location of localization band is insensitive to the interparticle spacing, but mainly determined by grain-level inhomogeneity. This is because the particles are dilute and small compared with the matrix grains. The particles, however, can decrease the localization strains when they straddle the localization band.

Ascorbic acid in the normal and regenerating tail of the house lizard, Hemidactylus flaviviridis

Development ◽  
1971 ◽  
Vol 26 (2) ◽  
pp. 285-293
Author(s):  
R. V. Shah ◽  
P. K. Hiradhar ◽  
D. K. Magon
Keyword(s):  
Wound Healing ◽  
Ascorbic Acid ◽  
Matrix Material ◽  
Growth Period ◽  
Tail Regeneration ◽  
The Matrix ◽  
Metabolic Activities ◽  
Vitamin Level ◽  
Hemidactylus Flaviviridis

The concentration of ascorbic acid (AA) and the histochemical distribution of the vitamin in the normal and regenerating tail of the gekkonid lizard, Hemidactylus flaviviridis, have been investigated. In the regenerating tail of the lizard the AA concentration almost doubles during wound healing and becomes fivefold during differentiation. However, it falls almost to the normal level during the blastema phase (i.e. period between wound healing and differentiation). Again, during the growth period (i.e. after differentiation) the AA concentration gradually becomes reduced, reaching the normal mark as the regenerate regains the full length of the original tail. Nevertheless, the vitamin level does not fall below the normal mark at any stage of regeneration. Increase of ascorbic acid during wound healing is thought to be mainly due to increased demand for the vitamin at the broken ends of the stump tissues, for their repair and formation of wound epithelium; the vitamin is known to help these processes. A fivefold increase of the vitamin during the differentiation period corresponds to an increased pace of laying down of the matrix material for the connective tissues, suggesting the role of ascorbic acid in the formation of collagen and mucopolysaccharides. Besides, the role of ascorbic acid in lipid and carbohydrate metabolism is also important during tail regeneration. Fluctuations in the vitamin level during different phases of tail regeneration are correlated with various states of metabolic activities of the corresponding phases.

Modified Anisotropic Gurson Yield Criterion for Porous Ductile Sheet Metals

2000 ◽  
Vol 123 (4) ◽  
pp. 409-416 ◽  
Author(s):  
W. Y. Chien ◽  
J. Pan ◽  
S. C. Tang
Keyword(s):  
Finite Element ◽  
Closed Form ◽  
Yield Criterion ◽  
Plastic Anisotropy ◽  
Matrix Material ◽  
Plastic Behavior ◽  
Computational Results ◽  
Sheet Metals ◽  
Element Analysis ◽  
The Matrix

The influence of plastic anisotropy on the plastic behavior of porous ductile materials is investigated by a three-dimensional finite element analysis. A unit cell of cube containing a spherical void is modeled. The Hill quadratic anisotropic yield criterion is used to describe the matrix normal anisotropy and planar isotropy. The matrix material is first assumed to be elastic perfectly plastic. Macroscopically uniform displacements are applied to the faces of the cube. The finite element computational results are compared with those based on the closed-form anisotropic Gurson yield criterion suggested in Liao et al. 1997, “Approximate Yield Criteria for Anisotropic Porous Ductile Sheet Metals,” Mech. Mater., pp. 213–226. Three fitting parameters are suggested for the closed-form yield criterion to fit the results based on the modified yield criterion to those of finite element computations. When the strain hardening of the matrix is considered, the computational results of the macroscopic stress-strain behavior are in agreement with those based on the modified anisotropic Gurson’s yield criterion under uniaxial and equal biaxial tensile loading conditions.

Functionally Graded Nanocomposites: Manufacturing and Characterization

Aerospace ◽  
2006 ◽  
Author(s):  
Jared A. Rud ◽  
Yuri M. Shkel ◽  
Donald R. Matthys ◽  
Jeffrey P. Davidson
Keyword(s):  
Electric Field ◽  
Carbon Nanofiber ◽  
Speckle Pattern ◽  
Matrix Material ◽  
Mechanical Analysis ◽  
Functionally Graded ◽  
Electronic Speckle Pattern Interferometry ◽  
Random Orientation ◽  
The Matrix ◽  
Particle Alignment

Multi-walled carbon nanofiber (MWCN) composites having tailored internal structure are created using Field Aided Micro Tailoring (FAiMTa) technology. FAiMTa is a technique that relies on the application of an electric field to a suspension while it cures. The particles in the suspension align in the direction of the electric field while the matrix material hardens, locking the aligned particles in place. The outcome is an orthotropic micro-tailored composite. Three 1% by volume MWCN/epoxy composite systems are manufactured and characterized: (a) random orientation, (b) fibers aligned through the thickness of the sample, and (c) half-aligned through the thickness and half random orientation. Electronic Speckle Pattern Interferometry (ESPI) and Dynamic Mechanical Analysis (DMA) are used to evaluate mechanical material properties as a function of particle alignment. The half aligned sample demonstrates the ability of FAiMTa to locally tailor a material.

Finite Element Analysis of the Effect of Cutting Speed on the Orthogonal Turning of A359/SiCp MMC

2016 ◽  
Vol 852 ◽  
pp. 304-310
Author(s):  
M.M. Thamizharasan ◽  
Y.J. Nithiya Sandhiya ◽  
K.S. Vijay Sekar ◽  
V.V. Bhanu Prasad
Keyword(s):  
Finite Element ◽  
Matrix Material ◽  
Cutting Speed ◽  
Depth Of Cut ◽  
Fe Model ◽  
Element Analysis ◽  
Damage And Fracture ◽  
Orthogonal Turning ◽  
The Matrix ◽  
Cutting Speeds

The application of Metal Matrix Composite (MMC) has been increasing due to its superior strength and wear characteristics but the major challenge is its poor machinability due to the presence of reinforcement in the matrix which is a hindrance during machining. The material behaviour during machining varies with respect to input variables. In this paper the effect of cutting speed during the orthogonal turning of A359/SiCp MMC with TiAlN tool insert is analysed by developing a 2D Finite Element (FE) model in Abaqus FEA code. The FE model is based on plane strain formulation and the element type used is coupled temperature displacement. The matrix material is modeled using Johnson–Cook (J-C) thermal elastic–plastic constitutive equation and chip separation is simulated using Johnson–Cook’s model for progressive damage and fracture with parting line. Particle material is considered to be perfectly elastic until brittle fracture. The tool is considered to be rigid. The FE model analyses the tool interaction with the MMC and its subsequent effects on cutting forces for different cutting speeds and feed rates. The chip formation and stress distribution are also studied. The FE results are validated with the experimental results at cutting speeds ranging from 72 – 188 m/min and feed rates ranging from 0.111 – 0.446 mm/rev at constant depth of cut of 0.5mm.

Numerical Modelling of the Strength of Highly Porous Aerated Autoclaved Concrete

1998 ◽  
Vol 521 ◽  
Author(s):  
Thomas Schneider ◽  
Georg Schober ◽  
Peter Greil
Keyword(s):  
Compressive Strength ◽  
Weibull Modulus ◽  
Building Materials ◽  
Matrix Material ◽  
Element Analysis ◽  
Porosity Distribution ◽  
High Mechanical Strength ◽  
The Matrix ◽  
Highly Porous ◽  
Weibull Theory

ABSTRACTHighly porous building materials like aerated autoclaved concrete are characterized by low thermal conductivity and high mechanical strength, which both strongly depend on porosity. The influence of porosity distribution on the compressive strength of aerated autoclaved concrete was investigated by using finite element analysis and multiaxial Weibull theory. Calculations of failure probability of microstructures with ordered as well as random pore configurations show a dependence of compressive strength on the Weibull modulus of the matrix material and the size and arrangement of pores. The results of the calculations are compared to experimental data of aerated autoclaved concrete.

scholarly journals The stress analysis of a shear wall with matrix displacement method using rectangular finite element

2021 ◽  
Vol 4 (1) ◽  
pp. 18-27
Author(s):  
Mustafa Ergün ◽  
Şevket Ateş
Keyword(s):  
Finite Element ◽  
Stress Analysis ◽  
Plane Stress ◽  
Shear Wall ◽  
Element Formulation ◽  
The Finite Element Method ◽  
Displacement Method ◽  
Element Analysis ◽  
The Matrix ◽  
Characteristic Features

The aim in this study is to numerically present some characteristic features of the rectangular finite element using the matrix displacement method and to show the utility of this element in plane stress problems compared to the finite element method. The paper consisted of three parts. In the first part, all of the finite element formulation steps from choosing the convenient coordinate system to creating element stiffness matrix are presented respectively. In the second part of the study, a static finite element analysis of the shear wall is also made by ANSYS Mechanical APDL. In the final part, the results (displacements, strains and stresses) obtained from the previous parts are compared with each other by the help of tables and graphics. The results show that this method is effective and preferable for the stress analysis of shell structures. Further studies should be conducted in order to indicate the efficiency of the matrix displacement method for the solution of different types of plane stress problems using different finite elements.

scholarly journals Физико-химические процессы, сопровождающие локализацию пластической деформации при импульсном нагружении

2021 ◽  
Vol 91 (3) ◽  
pp. 450
Author(s):  
С.Н. Буравова ◽  
И.С. Гордополова ◽  
Е.В. Петров
Keyword(s):  
Mass Transfer ◽  
Phase Composition ◽  
Damage Zone ◽  
Matrix Material ◽  
Cold Deformation ◽  
Decisive Role ◽  
Wave Mode ◽  
Spall Damage ◽  
The Matrix

Investigation of the strains development under pulsed loading showed the decisive role of powerful ultrasonic sample vibrations in the standing wave mode. The effect of mass transfer of atoms and ultrafine hardening phase particles from the matrix material to the spall damage zone on the strain bands microstructure is determined. Rapid cooling of the metal inside the localization bands, the size of which does not exceed several tens of microns, indicates that changes in the phase composition occur as a result of cold deformation. Rapid the metal cooling inside the localization bands, the size of which does not exceed several tens of microns, indicates that changes in the phase composition occur as a result of cold deformation.

Modeling of Plastic Behavior of Anisotropic Sheet Metals With Voids

2000 ◽  
Author(s):  
W. Y. Chien ◽  
J. Pan ◽  
S. C. Tang
Keyword(s):  
Finite Element ◽  
Closed Form ◽  
Yield Criterion ◽  
Plastic Anisotropy ◽  
Matrix Material ◽  
Three Dimensional ◽  
Plastic Behavior ◽  
Element Analysis ◽  
Normal Anisotropy ◽  
The Matrix

Abstract The influence of plastic anisotropy on the plastic behavior of porous ductile materials is investigated by a three-dimensional finite element analysis. A unit cell of cube containing a spherical void is modeled. The Hill quadratic anisotropic yield criterion is used to describe the matrix normal anisotropy and planar isotropy. The matrix material is assumed to be elastic perfectly plastic. Macroscopically uniform displacements are applied to the faces of the cube. The finite element computational results are compared with those based on the closed-form anisotropic Gurson yield criterion suggested in Liao et al. (Mechanics of Materials, 1997, pp. 213-226). Three fitting parameters are suggested in the closed-form yield criterion to fit the results based on the modified yield criterion to those of finite element computations.

Finite Element Analysis of Multiphase Viscoelastic Solids

1992 ◽  
Vol 59 (4) ◽  
pp. 730-737 ◽  
Author(s):  
L. C. Brinson ◽  
W. G. Knauss
Keyword(s):  
Finite Element ◽  
Volume Fraction ◽  
Matrix Material ◽  
Numerical Procedure ◽  
Element Model ◽  
Analytical Models ◽  
Frequency Range ◽  
Element Analysis ◽  
The Matrix ◽  
Composite Moduli

The properties of composite solids containing multiple, viscoelastic phases are studied numerically. The dynamic correspondence principle of viscoelasticity is utilized in a finite element model to solve boundary value problems for obtaining global complex moduli of the composite. This numerical procedure accounts for the coupled interactive deformation of the phases and thus the resultant accuracy is limited only by that of finite element analyses in general. The example composite considered in this study contains cylindrical viscoelastic inclusions embedded in a viscoelastic matrix. This investigation focuses on the global composite moduli and their relationship to the individual phase properties as a function of volume fraction. A given phase material is shown to have differing effects on the composite properties, depending on whether it is the continuous or the included phase: In general, the composite moduli are dominated by the matrix material. Comparison is made with two simple analytical models for global effective moduli of composites. “Upper Bounds” reproduce the behavior over the whole frequency range when the matrix is the “stiffer” of the two solids while the “lower bond” associates with the converse arrangement, also over the whole frequency range. The nature of time-temperature behavior of multiphase composite materials is examined in a companion paper.

scholarly journals Creep Response of Neat and Carbon-Fiber-Reinforced PEEK and Epoxy Determined Using a Micromechanical Model

Symmetry ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 1680
Author(s):  
Mostafa Katouzian ◽  
Sorin Vlase
Keyword(s):  
Carbon Fiber ◽  
Matrix Material ◽  
Micromechanical Model ◽  
Viscoelastic Behavior ◽  
Experimental Tests ◽  
Fiber Reinforced ◽  
Element Analysis ◽  
Nonlinear Viscoelastic ◽  
The Matrix ◽  
Carbon Fiber Reinforced

A micromechanical model is developed to study the creep phenomena with neat and carbon-fiber-reinforced PEEK (Polyetheretherketon) and epoxy. The model considers that the continuous elastic circular fibers form a regular array inside the matrix material. In this study, the fibers are considered to be linear elastic and anisotropic, while the matrix has a nonlinear viscoelastic behavior. The approach describes the time-dependent response of unidirectional viscoelastic composites subjected to various types of loading conditions. A comparison between the finite element analysis and the proposed micromechanical model shows a good agreement. Experimental tests validate the results obtained using the proposed theoretical model.

Sign in / Sign up

Export Citation Format

Share Document