Effective elastic moduli of a fibrous composite material, isotropic on the average

1977 ◽  
Vol 18 (2) ◽  
pp. 270-273
Author(s):  
V. V. Kolokol'chikov ◽  
G. N. Sapego
Keyword(s):  
Composite Material ◽  
Elastic Moduli ◽  
Fibrous Composite ◽  
Effective Elastic Moduli ◽  
Fibrous Composite Material

scholarly journals On the Theory of Elasticity of Microinhomogeneous Media with Account for Stochastic Changes in the Connectivity of Constituent Components

2021 ◽  
pp. 132-143
Author(s):  
L. A Saraev
Keyword(s):  
Differential Equation ◽  
Composite Material ◽  
Composite Materials ◽  
Numerical Solution ◽  
Elastic Moduli ◽  
Production Factor ◽  
Effective Elastic Moduli ◽  
Connectivity Function ◽  
Isotropic Composite ◽  
Random Connectivity

The paper proposes a mathematical model aimed at calculating the effective elastic moduli of a micro-inhomogeneous two-component isotropic composite material, which components are connected randomly depending on the level of their relative volumetric contents. A stochastic equation is formulated for the connectivity parameter of the constituent components, according to which, with an increase in the volumetric content of the filler, individual inclusions build the structures of the matrix mixture in the form of interpenetrating frameworks, and then turn into a new binding matrix with individual inclusions from the material of the rest of the old matrix. The algorithm for the numerical solution of this stochastic differential equation is constructed in accordance with the Euler-Maruyama method. For each implementation of this algorithm, the corresponding stochastic trajectories are constructed for the random connectivity function of the constituent components of the composite material. A variant of the method aimed at calculating the mathematical expectation of a random connectivity function of the constituent components has been developed and the corresponding differential equation has been obtained for it. It is shown that the numerical solution of this equation and the average value of the production factor function calculated for all realizations of stochastic trajectories give close numerical values. New macroscopic constitutive relations are found for microinhomogeneous materials with a variable microstructure and their effective elastic moduli are calculated. It is noted that the formulas for these effective elastic moduli generalize the known results for isotropic composite materials. The values of the effective elastic moduli, constructed according to the expressions obtained in the paper, lie within the Khashin-Shtrikman range for the lower and upper bounds of the effective elastic moduli of the composite materials. The numerical analysis of the developed models showed a good agreement with the known experimental data.

Finite Element Modeling of Steel Pipeline Reconstruction Using Fiberglass Composite Material

2015 ◽  
Vol 725-726 ◽  
pp. 648-653 ◽  
Author(s):  
Ekaterina A. Nekliudova ◽  
Artem S. Semenov ◽  
S.G. Semenov ◽  
Boris E. Melnikov
Keyword(s):  
Finite Element ◽  
Composite Material ◽  
Stress State ◽  
Elastic Moduli ◽  
Strength Properties ◽  
Geometrical Parameters ◽  
Effective Elastic Moduli ◽  
Composite Part ◽  
Steel Pipeline ◽  
Fiberglass Composite

A stress state of the partially damaged underground steel pipeline after reconstruction by means of the fiberglass composite material is considered. The strength properties of the composite are determined experimentally. The effective elastic moduli of the composite are determined by means of the finite element homogenization. Tsai-Wu failure criterion is used for the composite part of the pipeline. The influence of geometrical parameters and loading conditions on the safety factor of the pipeline is analyzed and discussed.

scholarly journals Analysis of the possibility of determining the internal structure of composite material by estimating its thermal diffusivity

2014 ◽  
Vol 35 (1) ◽  
pp. 3-15
Author(s):  
Stanisław Kucypera
Keyword(s):  
Composite Material ◽  
Heat Conduction ◽  
Thermal Diffusivity ◽  
Internal Structure ◽  
Fibrous Composite ◽  
Electric Heater ◽  
Transient Temperature ◽  
Inverse Heat Conduction ◽  
Filtration Method ◽  
Fibrous Composite Material

Abstract The aim of this paper is analysis of the possibility of determining the internal structure of the fibrous composite material by estimating its thermal diffusivity. A thermal diffusivity of the composite material was determined by applying inverse heat conduction method and measurement data. The idea of the proposed method depends on measuring the timedependent temperature distribution at selected points of the sample and identification of the thermal diffusivity by solving a transient inverse heat conduction problem. The investigated system which was used for the identification of thermal parameters consists of two cylindrical samples, in which transient temperature field is forced by the electric heater located between them. The temperature response of the system is measured in the chosen point of sample. One dimensional discrete mathematical model of the transient heat conduction within the investigated sample has been formulated based on the control volume method. The optimal dynamic filtration method as solution of the inverse problem has been applied to identify unknown diffusivity of multi-layered fibrous composite material. Next using this thermal diffusivity of the composite material its internal structure was determined. The chosen results have been presented in the paper.

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