research

 (in Computational Methods for Microstructure-Property Relationships," Springer. Edited by Somnath Ghosh and Dennis Dimiduk)

Dislocation mediated continuum plasticity: case studies on modeling scale dependence, scale-invariance, and directionality of sharp yield-point

Claude Fressengeas, Amit Acharya, Armand Beaudoin

I am working on a project "vehicle ride dynamics using component mode synthesis." I would be making a matlab code to determine the vehicle body response due to road excitation signals. I will be modelling the tyre stiffnesses using springs, suspension with springs and dampers and vehicle body using plate of varying stiffnesses. I want to know that how a vehicle body can be approximately modelled with a plate of varying stiffnesses so that it reflects the real car body, as just assuming it as plate( of constant stiffness) will be too crude approximation. Also i woluld like to compare various CMS methods like free interface, fixed interface, hybrid interface on this system. If anybody has done any work in this field please provide some guidance. 

Due to the migration of mobile molecules and ions, a thin diffusive layer of distributed charge - the electric double layer - forms at the interface between a polyelectrolyte gel and a liquid ionic solution.  When two polyelectrolyte gels are brought closely together, the electric double layers overlap and interact with each other, resulting in an effective repulsion.  The multiphysics coupling nature of soft gels makes their surface interactions significantly different from the interactions between rigid solids.

The electric-field-induced phase transition was investigated under mechanical confinements in bulk samples of an antiferroelectric perovskite oxide at room temperature. Profound impacts of mechanical confinements on the phase transition are observed due to the interplay of ferroelasticity and the volume expansion at the transition. The uniaxial compressive prestress delays while the radial compressive prestress suppresses it. The difference is rationalized with a phenomenological model of the phase transition accounting for the mechanical confinement.

In this paper, we study the effect of normal and shear strains and

oxygen vacancies on the structure of 180^o ferroelectric

domain walls in PbTiO_3.

Single-walled carbon nanotubes (SWNTs) possess extraordinary electrical and mechanical properties, with many possible applications in electronics and materials science. Dense, horizonally aligned arrays of linearly configured SWNTs represent perhaps the most attractive and scalable way to implement this class of nanomaterial in practical systems. Recent work shows that templated growth of tubes on certain crystalline substrates (e.g. quartz) yields arrays with the necessary levels of perfection, as demonstrated by the formation of devices and full systems on quartz.