iMechanica - ES 246 project: Planar Composite under Plastic Deformation - Comments

3D FEM modeling of composite materials is possible

Xuanhe Zhao — Thu, 11 Jan 2007 21:52:05 -0500

Now we can generate the mesh for the composite model with small balls as inclusion phase.

Micro-mechanical models?

Kristin M. Myers — Thu, 07 Dec 2006 13:42:23 -0500

This may fall out of the scope of your class project, but how does a micor-mechanical model compare to the discussed constitutive models you propose?

Time permitting, you can explore the results of the following paper:

Micromechanics, macromechanics and constitutive modeling of the elasto-viscoplastic deformation of rubber-toughened glassy polymers

Mats Danielsson, David M. Parks and Mary C. Boyce
Journal of the Mechanics and Physics of Solids, In Press, Corrected Proof, Available online 27 November 2006

Concerns on random heterogeneous media

Nanshu Lu — Wed, 06 Dec 2006 17:48:07 -0500

It's an interesting topic related to the applications of piezoelectrical materials. To deal with random heterogeneous media I simply have two concerns,

1. In order to say random-distributed second-phase particles, one need to be careful of the geometric design. For example, the proportion of length scales of particle vs. matrix, the particle spacing and so on.

2.Besides the geometrical characteristics of multiphase materials, an important aspect is the contrast between the different constituent materials, such as Young's modulus. As far as plasticity is concerned The ranges spanned by the yield stress are from 20 MPa to more than 1 GPa for metals and alloys, from a few MPa to 150 MPa for polymers, 1 to 10 GPa for ceramics.

For details, please consult

Syntheses: Mechanical properties of heterogeneous media: Which material for which model? Which model for which material? P Gilormini et al 1999 Modelling Simul. Mater. Sci. Eng. 7 805-816

ES 246 project: Planar Composite under Plastic Deformation

Xuanhe Zhao — Wed, 29 Nov 2006 21:30:49 -0500

The mechanical performance of a homogeneous material can be varied by the addition of second-phase particles. In this project, we will model a planar composite under plastic deformation. As shown on the following figure, the composite consists of matrix material and randomly-distributed inclusion particles. The matrix is assumed to be an elastic-plastic material with isotropic or kinematic hardenings, and the inclusion particle pure elastic with a higher Young’s modulus. The stress/strain field throughout the composite will be calculated numerically with finite element method. The effective constitutive behavior of the composite will be evaluated and compared with theoretical and experimental results from literature [1, 2].

[1] Torquato, S.: Random heterogeneous media: microstructure and improved bounds on effective properties. Appl. Mech. Rev. 44, 37-75 (1991)
[2] Ponte Castaneda, P.: The effective mechanical properties of nonlinear isotropic composite. J. Mech. Phys. Solids 39, 45-71 (1991).