Can the maximum volume fraction ensure optimum reinforcement in short‐fiber composites?

2019 ◽  
Vol 136 (31) ◽  
pp. 47821
Author(s):  
Florencia Cruces ◽  
María Guadalupe García ◽  
Nelio Ariel Ochoa
Keyword(s):  
Volume Fraction ◽  
Fiber Composites ◽  
Short Fiber ◽  
Maximum Volume ◽  
Optimum Reinforcement ◽  
Maximum Volume Fraction

Variant Selection in Zr Alloys: How Many Variants Generated from one Beta Grain?

2005 ◽  
Vol 105 ◽  
pp. 133-138 ◽  
Author(s):  
Pierre Barbéris ◽  
Frank Montheillet ◽  
Cédric Chauvy
Keyword(s):  
Elastic Energy ◽  
Volume Fraction ◽  
Variant Selection ◽  
Energy Minimum ◽  
Maximum Volume ◽  
Volume Fractions ◽  
Minimum Number ◽  
Simplifying Assumptions ◽  
Maximum Volume Fraction ◽  
Zr Alloys

The elastic energy of a set of the twelve variants generated during the b ® a transformation of zirconium, with volume fractions fi, i=1..12, is derived with simplifying assumptions and the conditions on the fi to reach the energy minimum are established analytically. The minimum number of variants needed to reach this minimum is shown to be 6, and in this case, the variants have very specific volume fractions. Another result is that the maximum volume fraction of any variant is 1/3.

Can the Strength of Brittle Materials be Enhanced?

1992 ◽  
Vol 291 ◽  
Author(s):  
L. Monette ◽  
M. P. Anderson ◽  
G. S. Grest
Keyword(s):  
Computer Model ◽  
Random Distribution ◽  
Load Transfer ◽  
Volume Fraction ◽  
Fiber Composites ◽  
Short Fiber ◽  
Particulate Composites ◽  
Second Phase ◽  
Two Dimensional ◽  
Fiber Volume

ABSTRACTWe have employed a two-dimensional computer model to study the effect of volume fraction of second phase constituents on load transfer (stiffness) and strength in brittle short-fiber composites, i.e. composites containing a random distribution of aligned fibers, and brittle particulate composites. We find that the efficiency of load transfer to the second phase consituent increases with volume fraction in particulate composites, while it decreases for short-fiber composites. The strength of brittle particulate composites is found to decrease, while the strength of brittle short-fiber composites marginally increases only at fiber volume fractions equal or greater than 0.25.

Cement Viscosity As A Function Of Concentration

1992 ◽  
Vol 289 ◽  
Author(s):  
Leslie J. Struble ◽  
Guo-Kuang Sun
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Portland Cement ◽  
Volume Fraction ◽  
Optimization Techniques ◽  
Viscosity Data ◽  
Maximum Volume ◽  
Cement Pastes ◽  
Maximum Volume Fraction ◽  
Measured Viscosity

AbstractThe Krieger-Dougherty equation allows calculation of viscosity as a function of volume fraction for suspensions of noninteracting particles. For model suspensions (of spherical, monosized particles), it has been shown to provide excellent agreement between calculated and measured viscosities. In the present study, this equation was applied to portland cement pastes, also with good correlations between calculated and measured viscosities. Because cement has a broad particle size distribution and its particles are angular and elongated, the two constants in this equation (the maximum volume fraction and the intrinsic viscosity) were estimated using nonlinear optimization techniques. The equation provides an excellent fit to measured viscosity data. However, the nature of the equation makes the estimation somewhat difficult, and the solutions are not well-defined.

A New Theory for the Debonding of Discontinuous Fibers in an Elastic Matrix

1989 ◽  
Vol 170 ◽  
Author(s):  
Christopher K. Y. Leung ◽  
Victor C. Li
Keyword(s):  
Fiber Length ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Interfacial Strength ◽  
Fiber Composites ◽  
Short Fiber ◽  
Fiber Volume ◽  
Physical Reason ◽  
Pull Out

AbstractThe mechanical properties of fiber composites are strongly influenced by the debonding of fibers. When an embedded fiber is loaded from one end, debonding can occur at both the loaded end and the embedded end. Existing theories neglect the possibility of debonding from the embedded end and are thus limited in applications to cases with low fiber volume fraction, low fiber modulus, high interfacial strength/interfacial friction ratio or short fiber length. A new twoway fiber debonding theory, which can extend the validity of one-way debonding theories to all general cases, has recently been developed. In this paper, the physical reason for the occurrence of two-way debonding is discussed. The limit of validity for one-way debonding theories is considered. One-way and two-way debonding theories are then compared with respect to the prediction of composite behaviour. The determination of interfacial parameters from the fiber pull-out test will also be described.

The Effect of Nano SiO2 Particle Size Distribution on Rheological Behaviour of Shear Thickening Fluids

2013 ◽  
Vol 58 (4) ◽  
pp. 1323-1326 ◽  
Author(s):  
A. Idźkowska ◽  
M. Szafran
Keyword(s):  
Particle Size ◽  
Shear Rate ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Volume Fraction ◽  
Ceramic Powder ◽  
Shear Thickening ◽  
Measuring System ◽  
Maximum Volume ◽  
Maximum Volume Fraction

Abstract In present work the influence of particle size distribution on the dilatant effect of shear thickening fluid was investigated. As a ceramic powder a mixture of silicas 200 and 7 nm in ratio 95:5, 90:10, 85:15, 80:20, 75:25, 50:50 was used. A dispersing agent was poly (propylene glycol) of a molecular weight of 425 g/mol. The as prepared slurries were examined on a rotational rheometer Kinexus Pro with a plate-plate measuring system at room temperature, where the viscosity as a function of shear rate was investigated. The measurement showed that by partially replacing greater particle size by smaller one, it is possible to shift the onset of shear thickening to the higher value of shear rate, however, the decreases of dilatant effect is observed. The influence of particle size distribution on a maximum volume fraction also was investigated. The maximum volume fraction which was passible to obtain was 35 vol%.

Bounds for Elastic Moduli of Multiphase Short-Fiber Composites

1984 ◽  
Vol 51 (3) ◽  
pp. 540-545 ◽  
Author(s):  
S. Nomura ◽  
T.-W. Chou
Keyword(s):  
Elastic Modulus ◽  
Aspect Ratio ◽  
Correlation Functions ◽  
Volume Fraction ◽  
Perturbation Expansion ◽  
Effective Elastic Modulus ◽  
Fiber Composites ◽  
Short Fiber ◽  
Spherical Particles ◽  
Upper And Lower Bounds

This paper examines upper and lower bounds of the effective elastic modulus of unidirectional short-fiber composites. The short-fibers are modeled by aligned ellipsoidal inclusions of the same aspect ratio but not necessarily the same size. We adopt a perturbation expansion of the composite local strain field by using the Green function tensor. Explicit expressions of the effective elastic modulus are derived up to the third-order term by use of the information on the correlation functions. The variational method is then employed to optimize the bounds of the effective modulus in a closed form. Numerical examples of the bounds as functions of the fiber aspect ratio and the fiber volume fraction are given for a glass/epoxy system. The present approach predicts narrower bounds than those of Hashin and coworkers for the limiting cases of spherical particles and continuous fibers since their bounds corresponds to a model that take the correlation functions up to the second order into account.

Study of Retained Austenite in Q&P Steel for Automobile

2012 ◽  
Vol 482-484 ◽  
pp. 1436-1441 ◽  
Author(s):  
Bao Tong Zhuang ◽  
Hai Tao Jiang ◽  
Di Tang ◽  
Zhen Li Mi ◽  
Zhen Kuai
Keyword(s):  
Grain Boundaries ◽  
Retained Austenite ◽  
Volume Fraction ◽  
Carbon Partitioning ◽  
Maximum Volume ◽  
Quenching And Partitioning ◽  
Maximum Volume Fraction ◽  
Intercritical Region

Retained austenite of Q&P (Quenching and Partitioning) processed 0.2C-1.51Si-1.84Mn steel heated in intercritical region and full austenite region are investigated. The results show that the maximum volume fraction of retained austenite heated in intercritical and full austenite region is 13.39% and 5.23% respectively. Carbon partitioning completed within 10 s for both heating modes. The microstructure after full austenitization consisted of martensite laths and thin, inter-lath retained austenite film. Austenite blocks is observed as well after partial austenitization.The distribution of retained austenite is related to the amount of grain boundaries by EBSD techniques.

scholarly journals Rheology of concentrated suspensions of non-colloidal rigid fibres

2017 ◽  
Vol 827 ◽  
Author(s):  
Franco Tapia ◽  
Saif Shaikh ◽  
Jason E. Butler ◽  
Olivier Pouliquen ◽  
Élisabeth Guazzelli
Keyword(s):  
Friction Coefficient ◽  
Aspect Ratio ◽  
Volume Fraction ◽  
Normal Stresses ◽  
Maximum Volume ◽  
Concentrated Suspensions ◽  
Suspension Flows ◽  
Jamming Transition ◽  
Aspect Ratios ◽  
Maximum Volume Fraction

Pressure- and volume-imposed rheology is used to study suspensions of non-colloidal, rigid fibres in the concentrated regime for aspect ratios ranging from 3 to 15. The suspensions exhibit yield stresses. Subtracting these apparent yield stresses reveals a viscous scaling for both the shear and normal stresses. The variation in aspect ratio does not affect the friction coefficient (ratio of shear and normal stresses), but increasing the aspect ratio lowers the maximum volume fraction at which the suspension flows. Constitutive laws are proposed for the viscosities and the friction coefficient close to the jamming transition.

Synthesis and Structural Characterization of Nanoscale BaTiO3 Powders

2007 ◽  
Vol 558-559 ◽  
pp. 1323-1327
Author(s):  
S.M. Moon ◽  
Nam Hee Cho
Keyword(s):  
Raman Spectroscopy ◽  
Structural Characterization ◽  
Tetragonal Phase ◽  
Volume Fraction ◽  
Relative Volume ◽  
Maximum Volume ◽  
Thermal Synthesis ◽  
Relative Volume Fraction ◽  
Maximum Volume Fraction

Nanoscale BaTiO3 powders were prepared by hydro-thermal synthesis as a function of solvent conditions. The size of the BaTiO3 powders was in the range of 20 ~ 100 nm. The variation in the relative volume fraction of the tetragonal phase was analyzed quantitatively by means of XRD and Raman spectroscopy. It was found that the maximum volume fraction of the tetragonal phase was ~ 29 %; this was obtained when the synthesis was performed at a solvent condition R (H2O/(H2O + EtOH)) = 0.25.

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