Influence of the Micromechanics Models and Volume Fraction Distribution on the Overall Behavior of SiC/Al Functionally Graded Pressurized Cylinders

Abstract

The assessment of the differences in results obtained from various micromechanics homogenization schemes, as well as the implications of assuming different volume fraction profiles was carried out in the present work. The functionally graded composite chosen for the analysis was Al-SiC and comparisons were made in terms of stress and strain distributions along the wall of an internally pressurized hollow cylinder. Different micromechanics homogenization schemes were implemented into Abaqus as user-defined subroutines (UMAT). The numerical simulations were compared to a set of analytical solutions available on the literature. The obtained results varied substantially according to the homogenization scheme employed. It was also found that the type of function chosen to describe the volume fraction distribution plays a major role on the development of the hoop stresses. Additionally, the finite element analysis showed significant stress variation when the actual volume fraction distribution was used. These gradients did not appear when the same profile was approximated by smooth exponential functions. This paper points out some important issues related to common practices associated with the analysis of FGM composites and serves as an overture to a more in-depth discussion of such problems.

Surrogate based optimization of functionally graded plates using radial basis functions

“…The evaluation of effective material properties requires the use of an appropriate homogenization scheme [40,1,41]. The simplest and most used approach is the Voigt model, also known as the Rule of Mixtures (RoM), where the effective material property (P) is given by the weighted average of the constituents properties:…”

“…The Voigt model gives good results for the specific mass (ρ), but poor results for other mechanical properties. Therefore, the elastic properties will be computed in this work using the Mori-Tanaka model [40,1,41]. Considering a matrix with spherical inclusions, the bulk modulus (K) and the shear modulus (G) are given by [42,43]:…”