Design and Effective Properties of a Functionally Graded Unidirectional Fiber-Reinforced Composite

2015 ◽  
Author(s):  
Satyajit Panda
Keyword(s):  
Elastic Properties ◽  
Volume Fraction ◽  
Effective Properties ◽  
Coupled Analysis ◽  
Sigmoid Function ◽  
Thickness Direction ◽  
Fiber Reinforced ◽  
Fiber Reinforced Composite ◽  
Representative Volume ◽  
Reinforced Composite

The present work deals with the design of a fiber-reinforced composite lamina with varying fiber-volume fraction (FVF) along its thickness direction. In the available elastic analyses of this kind of composite, the elastic properties are evaluated based on the assumptions like continuous variation of FVF and existence of decoupled representative volume element (RVE) at every point along the thickness direction. In order to predict the graded material properties without any of these assumptions at present, first a micro-structure of similar graded composite is designed for the variation of FVF according to a sigmoid function of thickness coordinate. Next, a continuum micro-mechanics finite element model of the corresponding representative volume (RV) is derived. The RV is basically composed of several micro-volumes of different FVFs and the classical homogenization treatment is implemented over these micro-volumes without decoupling them from the overall volume of RV. The importance of this coupled analysis is verified through a parallel decoupled analysis. The effect of the total number of micro-volumes within a specified thickness of lamina on its graded elastic properties is presented. The characteristics of graded elastic properties according to the sigmoid function are also discussed.

Mathematical Model of the Effective Properties of a Fiber Reinforced Composite with a Linearly Graded Transition Zone

2010 ◽  
Vol 38 (4) ◽  
pp. 286-307
Author(s):  
Carey F. Childers
Keyword(s):  
Mathematical Model ◽  
Transition Zone ◽  
Effective Properties ◽  
Local Stress ◽  
Stress And Strain ◽  
Fiber Reinforced ◽  
Strain Fields ◽  
Shear Moduli ◽  
Fiber Reinforced Composite ◽  
Reinforced Composite

Abstract Tires are fabricated using single ply fiber reinforced composite materials, which consist of a set of aligned stiff fibers of steel material embedded in a softer matrix of rubber material. The main goal is to develop a mathematical model to determine the local stress and strain fields for this isotropic fiber and matrix separated by a linearly graded transition zone. This model will then yield expressions for the internal stress and strain fields surrounding a single fiber. The fields will be obtained when radial, axial, and shear loads are applied. The composite is then homogenized to determine its effective mechanical properties—elastic moduli, Poisson ratios, and shear moduli. The model allows for analysis of how composites interact in order to design composites which gain full advantage of their properties.

Short Fiber Reinforced Composite: The Effect of Fiber Length and Volume Fraction

2006 ◽  
Vol 7 (5) ◽  
pp. 10-17 ◽  
Author(s):  
Lippo V.J. Lassila ◽  
Pekka K. Vallittu ◽  
Sufyan K. Garoushi
Keyword(s):  
Mechanical Properties ◽  
Fiber Length ◽  
Volume Fraction ◽  
Testing Machine ◽  
Short Fiber ◽  
Bending Test ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Fiber Reinforced Composite ◽  
Reinforced Composite

Abstract Aim The aim of this study was to determine the effect of short fiber volume fraction and fiber length on some mechanical properties of short fiber-reinforced composite (FRC). Methods and Materials Test specimens (2 x 2 x 25 mm3) and (9.5 x 5.5 x 3 mm3) were made from short random FRC and prepared with different fiber volumes (0%-22%) and fiber lengths (1-6 mm). Control specimens did not contain fiber reinforcement. The test specimens (n=6) were either dry stored or thermocycled in water (x10.000, 5 – 55°C) before loading (three-point bending test) according to ISO 10477 or statically loaded with a steel ball (Ø 3.0 mm) with a speed of 1.0 mm/min until fracture. A universal testing machine was used to determine the flexural properties and the load-bearing capacity. Data were analyzed using analysis of variance (ANOVA) (p=0.05) and a linear regression model. Results The highest flexural strength and fracture load values were registered for specimens with 22 vol% of fibers (330 MPa and 2308 N) and with 5 mm fiber length (281 MPa and 2222 N) in dry conditions. Mechanical properties of all test specimens decreased after thermocycling. ANOVA analysis revealed all factors were affected significantly on the mechanical properties (p<0.001). Conclusions By increasing the volume fraction and length of short fibers up to 5 mm, which was the optimum length, the mechanical properties of short FRC were improved. Citation Garoushi SK, Lassila LVJ, Vallittu PK. Short Fiber Reinforced Composite: The Effect of Fiber Length and Volume Fraction. J Contemp Dent Pract 2006 November;(7)5:010-017.

Sign in / Sign up

Export Citation Format

Share Document