Analytical Solutions for Effective Axial Mechanical Properties of a Three-Phase Active Fiber Composite Model

2007 ◽  
Author(s):  
Davood Askari ◽  
Mehrdad N. Ghasemi Nejhad
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Analytical Solutions ◽  
Fiber Composite ◽  
Fiber Composites ◽  
Orthotropic Materials ◽  
Exact Analytical Solutions ◽  
Active Fiber ◽  
Three Phase ◽  
Active Fiber Composites

Active fiber composites are among the many other components used in intelligent and smart composite structures which undergo mechanical deformation upon the application of external loads or electric fields. This work presents an analytical approach for derivations of exact solutions for the effective axial mechanical properties of active fiber composites with circular cross-sections, and while the properties of the constituent materials are considered to be generally orthotropic. First, exact analytical solutions of the effective longitudinal Young’s modulus and Poisson’s ratio are obtained for a three-phase composite cylindrical model composed of orthotropic materials. Next, Finite element analysis, as an alternative approach, is performed to numerically determine the effective axial properties of an identical three-phase composite cylinder. Finally, effective material properties obtained from analytical and finite element methods are compared to verify the derived analytical solutions. Excellent agreements are achieved between the results obtained from both techniques validating the exact analytical solutions.

Analytical Solutions for Effective Axial Mechanical Properties of Active Fiber Composites

Aerospace ◽  
2006 ◽  
Author(s):  
Davood Askari ◽  
Mehrdad N. Ghasemi Nejhad
Keyword(s):  
Mechanical Properties ◽  
Exact Solutions ◽  
Cross Sections ◽  
Analytical Solutions ◽  
Fiber Composites ◽  
Orthotropic Materials ◽  
Young’S Moduli ◽  
Active Fiber ◽  
Active Fiber Composites ◽  
Effective Mechanical Properties

This work presents analytical solutions for the effective axial mechanical properties of the active fiber composites with different geometries, e.g., circular and rectangular cross-sections, and while the properties of the constituent materials are considered to be generally orthotropic. Analytical exact solutions of the effective longitudinal Young's moduli and major Poisson's ratios are obtained for two different geometries of a 2-phase composite model composed of orthotropic materials. Finite element analyses (FEAs) are also performed to verify the obtained analytical exact solutions. Excellent agreements are achieved between the results obtained from both techniques. Finally, the effective mechanical properties calculated from analytical solutions for the modeled geometrical configurations are compared.

Micromechanics of Longitudinal Mechanical Properties for Active Fiber Composites With Embedded Metal-Core Piezoelectric Fibers

Aerospace ◽  
2005 ◽  
Author(s):  
Mehrdad N. Ghasemi Nejhad ◽  
Davood Askari
Keyword(s):  
Mechanical Properties ◽  
Fiber Composite ◽  
Transversely Isotropic ◽  
Fiber Composites ◽  
Core Material ◽  
Metal Core ◽  
Element Analysis ◽  
Active Fiber ◽  
Active Fiber Composites ◽  
Piezoelectric Fiber

An analytical micromechanics approach is presented to model the effective longitudinal mechanical properties of Metal-Core Piezoelectric Fibers (MPF). The model assumes general orthotropic material properties for the piezoelectric as well as the core material. Next, the general orthotropic solution is reduced to transversely isotropic for the piezoelectric fiber and isotropic for the metal-core. This MPF system is also modeled using finite element analysis (FEA) and the results from the analytical solution and FEA are compared for verification purpose. Next, the Metal-Core Piezoelectric Fiber (MPF) is embedded inside a metal or a polymer and the resulting longitudinal mechanical properties of these Active Fiber Composite (AFC) systems are given analytically.

scholarly journals Mathematical Modeling of an Active-Fiber Composite Energy Harvester with Interdigitated Electrodes

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
A. Jemai ◽  
F. Najar ◽  
M. Chafra ◽  
Z. Ounaies
Keyword(s):  
Finite Element ◽  
Energy Harvesting ◽  
Dynamic Behavior ◽  
Structural Model ◽  
Piezoelectric Materials ◽  
Fiber Composite ◽  
Interdigitated Electrodes ◽  
Active Fiber ◽  
Active Fiber Composites ◽  
Composite Energy

The use of active-fiber composites (AFC) instead of traditional ceramic piezoelectric materials is motivated by flexibility and relatively high actuation capacity. Nevertheless, their energy harvesting capabilities remain low. As a first step toward the enhancement of AFC’s performances, a mathematical model that accurately simulates the dynamic behavior of the AFC is proposed. In fact, most of the modeling approaches found in the literature for AFC are based on finite element methods. In this work, we use homogenization techniques to mathematically describe piezoelectric properties taking into consideration the composite structure of the AFC. We model the interdigitated electrodes as a series of capacitances and current sources linked in parallel; then we integrate these properties into the structural model of the AFC. The proposed model is incorporated into a vibration based energy harvesting system consisting of a cantilever beam on top of which an AFC patch is attached. Finally, analytical solutions of the dynamic behavior and the harvested voltage are proposed and validated with finite element simulations.

A Comparative Finite Element Analysis of Residual Stresses in Active Fiber Composites With Embedded Metal-Core Piezoelectric Fibers and Macro Fiber Composites

Aerospace ◽  
2005 ◽  
Author(s):  
Davood Askari ◽  
Hiroshi Asanuma ◽  
Mehrdad N. Ghasemi-Nejhad
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Residual Stresses ◽  
Coefficient Of Thermal Expansion ◽  
Fiber Composites ◽  
Stress And Strain ◽  
Metal Core ◽  
Element Analysis ◽  
Active Fiber ◽  
Active Fiber Composites

Residual stresses are basically developed due to intrinsic and extrinsic strains that form during the processing of composite materials. The extrinsic strains can be determined using Coefficient of Thermal Expansion (CTE), material properties, geometry of the structure, and processing conditions. Finite Element Method (FEM) as an efficient alternative technique for stress and strain analysis of the micromechanical systems and structures, has been employed to numerically investigate the residual stresses developed in Metal-Core Piezoelectric Fibers (MPF) and Active Fiber Composites (AFC) (or Macro Fiber Composites (MFC)), during the processing. Here in this work, ANSYS Finite Element Analysis (FEA) software is used to develop three different 3-dimensional models for MPF and MFC structures and then each model is solved for strain and stress results. Next, the stress and strain components of these models are studied throughout the structures to identify the magnitude and type of the stresses and strains within the constituent materials and then compared.

scholarly journals Free Vibrations of Sandwich Plates with Damaged Soft-Core and Non-Uniform Mechanical Properties: Modeling and Finite Element Analysis

Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2444 ◽  
Author(s):  
Michele Bacciocchi ◽  
Raimondo Luciano ◽  
Carmelo Majorana ◽  
Angelo Marcello Tarantino
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Thickness Distribution ◽  
Free Vibrations ◽  
Soft Core ◽  
Sandwich Plates ◽  
Element Analysis ◽  
Three Phase ◽  
Reinforcing Fibers ◽  
Parametric Analyses

The paper aims to investigate the natural frequencies of sandwich plates by means of a Finite Element (FE) formulation based on the Reissner-Mindlin Zig-zag (RMZ) theory. The structures are made of a damaged isotropic soft-core and two external stiffer orthotropic face-sheets. These skins are strengthened at the nanoscale level by randomly oriented Carbon nanotubes (CNTs) and are reinforced at the microscale stage by oriented straight fibers. These reinforcing phases are included in a polymer matrix and a three-phase approach based on the Eshelby-Mori-Tanaka scheme and on the Halpin-Tsai approach, which is developed to compute the overall mechanical properties of the composite material. A non-uniform distribution of the reinforcing fibers is assumed along the thickness of the skin and is modeled analytically by means of peculiar expressions given as a function of the thickness coordinate. Several parametric analyses are carried out to investigate the mechanical behavior of these multi-layered structures depending on the damage features, through-the-thickness distribution of the straight fibers, stacking sequence, and mass fraction of the constituents. Some final remarks are presented to provide useful observations and design criteria.

Pultrusion Technology Optimization for Hybrid Fiber Composites Based on DSC and Mechanical Property Testing

2011 ◽  
Vol 295-297 ◽  
pp. 383-387 ◽  
Author(s):  
Li Chen ◽  
Qi Lin Zhao ◽  
Ke Bin Jiang ◽  
Yong Ding
Keyword(s):  
Mechanical Properties ◽  
Fiber Composite ◽  
Processing Parameters ◽  
Fiber Composites ◽  
Processing Temperature ◽  
Processing Parameter ◽  
Heating Rates ◽  
Hybrid Fiber ◽  
Scanning Calorimetry ◽  
Parameter Ranges

In the interest of improving the curing effect and mechanical properties of pultruded carbon/glass bybrid fiber composites, the DSC (Differential Scanning Calorimetry) technology was introduced and the curing DSC curves for the hybrid fiber composites at 4 different heating rates was attained. Then the range of the processing temperature for the three-stage heating pultrusion was primarily determined with T-β method. Subsequently a kind of carbon/glass hybrid composite pole with a diameter of 11mm was selected as the research object, and was manufactured with varies of processing temperatures and speeds. The produced poles were mechanically tested to investigate the effect of processing parameters on the mechanical properties of the composite, so as to further more ascertain the processing parameter ranges fitting to this material formula. As the result shows: the pultrusion processing parameters for the hybrid fiber composite acquired in this study can satisfy the require of manufacturing; compared with the traditional method that attain processing parameters by experience, the method for attaining processing parameters suggested in this paper is more efficiency, more economical and more accurate.

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