scholarly journals An approach to characterize dielectric properties of fiber-reinforced composites with high volume fraction

2016 ◽  
Vol 65 (2) ◽  
pp. 024102
Author(s):  
Liao Yi ◽  
Cai Kun ◽  
Zhang Yuan ◽  
Wang Xiao-Bing
Keyword(s):  
Dielectric Properties ◽  
Volume Fraction ◽  
High Volume ◽  
High Volume Fraction ◽  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Fiber Reinforced

scholarly journals Multiscale thermomechanical modeling of short fiber-reinforced composites

2017 ◽  
Vol 24 (5) ◽  
pp. 765-772 ◽  
Author(s):  
Dawei Jia ◽  
Huiji Shi ◽  
Lei Cheng
Keyword(s):  
Thermal Loading ◽  
Volume Fraction ◽  
Numerical Procedure ◽  
Thermal Conditions ◽  
Cyclic Hardening ◽  
Short Fiber ◽  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Thermomechanical Modeling

AbstractA study of the micromechanical behavior to predict the overall response of short fiber-reinforced composites under cyclic mechanical and thermal loading is presented. The instantaneous average over a “representative volume” of the material is considered. The influence of the short fiber’s aspect ratio, volume fraction, and spatial orientation has been investigated. The linear combined hardening model is used to describe the cyclic hardening effects in the case of metal matrix. A numerical procedure is used to predict the response of composites under mechanical and thermal conditions. The results of the numerical procedure have been compared to the results of three different models and to published experimental data.

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.

ARTIFICIAL GENERATION OF 2-D FIBER REINFORCED COMPOSITE MICROSTRUCTURES WITH STATISTICALLY EQUIVALENT FEATURES

2021 ◽  
Author(s):  
JAMAL F. HUSSEINI ◽  
SCOTT E. STAPLETON ◽  
EVAN J. PINEDA
Keyword(s):  
Volume Fraction ◽  
Real Life ◽  
High Strength ◽  
Material Behavior ◽  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Equivalent Models ◽  
Reinforced Composite ◽  
Low Weight

Fiber reinforced composites are used widely for their high strength and low weight advantages in various aerospace and automotive applications. While their use may be sought after, modeling of these material requires increasing fidelity at the lower scales to capture accurate material behavior under loading. The first steps in creating statistically equivalent models to real life cases is developing a method of rapid evaluation and artificial microstructure generation. The outlined work is capable of tracking microscale fiber positions and determining regions of localized volume fraction extrema (high and low end). Groupings of high and low volume fraction regions are called clusters and their geometry is used to characterize the microstructure. These cluster features can be evaluated for both artificial models and actual scans, allowing correlation to be established which can ultimately be used to regenerate statistically equivalent models. The results of this work show that if one feature is to be correlated, a model can be generated which matches almost exactly. But once more features are equally taken into account, the regeneration loses accuracy.

scholarly journals An Energy-Based Model of Longitudinal Splitting in Unidirectional Fiber-Reinforced Composites

1999 ◽  
Vol 67 (3) ◽  
pp. 437-443 ◽  
Author(s):  
K. Oguni ◽  
G. Ravichandran
Keyword(s):  
Volume Fraction ◽  
Effective Properties ◽  
Confining Pressure ◽  
Fiber Reinforced Composites ◽  
Fiber Direction ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Unidirectional Fiber ◽  
Longitudinal Splitting

Unidirectional fiber-reinforced composites are often observed to fail in a longitudinal splitting mode in the fiber direction under far-field compressive loading with weak lateral confinement. An energy-based model is developed based on the principle of minimum potential energy and the evaluation of effective properties to obtain an analytical approximation to the critical stress for longitudinal splitting. The analytic estimate for the compressive strength is used to illustrate its dependence on material properties, surface energy, fiber volume fraction, fiber diameter, and lateral confining pressure. The predictions of the model show good agreement with available experimental data. [S0021-8936(00)02003-1]

scholarly journals A novel determination of the minimal size of a probabilistic representative volume element for fiber-reinforced composites’ thermal analysis

2018 ◽  
Vol 22 (6 Part A) ◽  
pp. 2551-2564
Author(s):  
Zecan Tu ◽  
Junkui Mao ◽  
Junjun Mao ◽  
Hua Jiang
Keyword(s):  
Thermal Conductivity ◽  
Thermal Analysis ◽  
Heat Flux ◽  
Thermal Gradient ◽  
Volume Fraction ◽  
Volume Element ◽  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Minimal Size ◽  
Fiber Reinforced

In order to provide an accurate thermal analysis method of fiber-reinforced composites, a novel model based on a probabilistic representative volume element (RVE) is presented in this paper. Monte Carlo methods, probability analysis and finite element analysis have been applied together. The effective transverse thermal conductivity, heat flux field, and thermal gradient field of typical fiber-reinforced composites are examined. The criteria of RVE have been determined, and the minimal size for thermal analysis is obtained using the main statistics and the cross-entropy theory. At the same time, the fiber-to-matrix ratio of thermal conductivity and volume fraction have been changed to determine the influence on heat transfer inside fiber-reinforced composites. It is shown that different purposes of simulations lead to different minimal RVE sizes. The numerical results indicate that the non-dimensional minimal RVE sizes for calculating the effective thermal conductivity, heat flux, and thermal gradient are 30, 80, and 80, respectively. Compared with the volume fraction, the fiber-to-matrix ratio of the thermal conductivity has a more significant effect on minimal RVE size. When the thermal conductivity ratio increases, the minimal size of the RVE increases at first, then it remains almost unchanged.

scholarly journals A Stochastic Homogenized Peridynamic Model for Intraply Fracture in Fiber-Reinforced Composites

2019 ◽  
Author(s):  
Javad Mehrmashhadi ◽  
Ziguang Chen ◽  
Jiangming Zhao ◽  
Florin Bobaru
Keyword(s):  
Failure Modes ◽  
Volume Fraction ◽  
Crack Opening ◽  
Computational Cost ◽  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Peridynamic Model ◽  
Loading Case

The quasi-static transverse fracture behavior in unidirectional fiber-reinforced composites (FRCs) is investigated using a new intermediately-homogenized peridynamic (IH-PD) model and a fully homogenized peridynamic (FH-PD) model. The novelty in the IH-PD model here is accounting for the topology of the fiber-phase in the transverse sample loading via a calibration to the Halpin-Tsai model. Both models can capture well the measured load-displacement behavior observed experimentally for intraply fracture, without the need for an explicit representation of microstructure geometry of the FRC. The IH-PD model, however, is more accurate and produces crack path tortuosity as well as a non-monotonic load-crack-opening softening curve, similar to what is observed experimentally. These benefits come from the preservation of some micro-scale heterogeneity, stochastically generated in the IH-PD model to match the composite’s fiber volume fraction, while its computational cost is equivalent to that of an FH-PD model. We also present a three-point bending transverse loading case in which the two models lead to dramatically different failure modes: the FH-PD model shows that failure always starts from the off-center pre-notch, while the IH-PD model, when the pre-notch is sufficiently off-center, finds that the composite fails from the center of the sample, not from the pre-notch. Experiments that can confirm these findings are sought.

Sign in / Sign up

Export Citation Format

Share Document