Simulation on the Effect of Porosity in the Elastic Modulus of SiC Particle Reinforced Al Matrix Composites

Abstract

Although the porosity in Al-SiC metal matrix composites (MMC) can be diminished; its existence is unavoidable. The purpose of this work is to study the effect of porosity on Young's modulus of SiC reinforced aluminum matrix composites. Finite element analysis is performed based on the unit cell and the representative volume element approaches. The reliability of the models is validated by comparing the numerical predictions against several experimental data ranging in lowand high-volume fractions and good agreement is found. It is found that despite the stress transfer from the soft matrix to the reinforcement remains effective in the presence of pores, there is a drop in the stress gathering capability of the particles and thus, the resulting effective elastic modulus of composite decreases. The elastic property of the composite is more sensitive to pores away the reinforcement. It is confirmed, qualitatively, that the experimentally reported in the literature decrease in the elastic modulus is caused by the presence of pores.

Mechanical behavior of glass fiber‐reinforced Nylon‐6 syntactic foams and its Young's modulus numerical study

“…However, if a certain volume fraction is exceeded, it gives rise to a situation similar to having a significant number of pores in the composite, because the load transfer occurs more readily in the HGMs rather than the fiber, which is expected to be the reinforcement. Since the pores produce elastic relaxation, which leads to the HGMs undergoing increased loads (stress concentrator), there is a drop in its stress‐gathering capability for a given wall thickness, and consequently, the effective elastic modulus of the composite decreases 42 . As a result of the easy transfer of load to microspheres, thicker walls are necessary to delay the elastic relaxation of the microspheres and the impairing of the composite as a whole, in the context of strength.…”

“…The FEA was performed using the mechanic's module in the software Comsol Multiphysics. The procedure used to relate the actual heterogeneous composite and the homogeneous medium by averaging the stress and strain tensors over the volume of the unit cell, is reported in reference 42 . The uniaxial compressive stress of 60 Pa was applied.…”

“…The uniaxial compressive stress of 60 Pa was applied. It is considered that gas inside the sphere has zero‐moduli and zero Poisson's ratio, which means that the stress is zero, but not the strain 42 . For the simulation of the GRSF, the material properties, and geometrical parameters were the same as those used by Gupta, 35 except that the relative wall thickness was η=0.04.…”

Numerical Study Using Microstructure Based Finite Element Modeling of the Onset of Convective Heat Transfer in Closed-Cell Polymeric Foam

“…The effective thermal conductivity is considered as additive contributions of the conductive ( ) and convective ( ) paths . More details on the numerical methodology for averaging quantities over the surface of the REV (2 D domain), used to predict material parameters (thermal conductivity) from constitutive equations (Fourier’s law) can be found in [ 10 ], which was also used to predict material parameters over volume microstructural analysis [ 26 , 27 ] using COMSOL Multiphysics.…”

“…Regardless of the method used to construct the microstructure of the closed-cell foam for numerical analysis, typically, the finite element analysis (FEA) relies on the concept of the representative elementary volume (REV) of the material, which comprises a predetermined number of cells, voids, or inclusions to relate the heterogeneous material to the homogeneous medium using computational homogenization [ 10 ]. The REV represents the smallest volume of material that describes the global characteristics of the material [ 10 ]. Although finite element analysis is computationally expensive, it may account for the thermal behavior concerning the actual microstructure, i.e., randomly oriented cells, and the inhomogeneity in the size and shape of cells or cavities.…”