Pradeep Sharma's blog

Micromechanics---loosely speaking, is the study of heterogeneities in materials and its consequences for material or continuum behavior. This encompasses studies of inclusions, dislocations, cracks or more generally defects. A related problem is that of "coarse-graining" or in other words the effective homogenized properties of a heterogeneous material. The latter is a recurring theme in all of physical sciences not just solid mechanics. Micromechanics, a formidable subject by all means, dominated a substantial part of the history of solid mechanics. Several of our Timoshenko awardees have been associated with this subject, e.g. Eshelby, Hill, Keller, Irwin, Rice among others.

In a recent rapid communication (see attached paper), using principles of pattern formation, we expose some simple stategies to reliably produce perfect long range order in self-assembling systems. Most self-assembling systems exhibit short ranged order. This imperfection is detrimental to several practical applications. It is almost always possible to produce perfect patterns in small domain sizes but self-assembly over a larger areal span results in defects.

Xin-Lin Gao and I had the pleasure of guest-editing a special  issue on "scale effects in mechanics" for the journal, Mathematics and Mechanics of Solids (editor: Professor David Steigmann , UC Berkeley).

(Carbon) Nanotubes have attracted considerable attention from the mechanics community; probably second to none when it comes to nanotechnologies. Although I personally have done very little in this particular topic, I have enjoyed reading about the many developments made by mechanicians in terms of modeling the behavior of nanotubes and the applicability of standard continuum mechanics notions. A post on this subject on iMechanica, which received a fair amount of attention from many mechanicians involved in this topic, may be found here .

University of Houston

Department of Mechanical Engineering

Cullen College of Engineering

Faculty Position-Nano Mechanics, Nano Materials

For many mechanicians and materials scientists one of the most confounding things (in the ever increasing literature on carbon nanotubes) is the reported theoretical value of the nanotube elastic modulus. Depending upon the specific paper at hand, the reported numerical values range from 1 -6 TPa!

I had posted this on the amd blog...I am posting it here as well:

I thought I should take advantage of iMechanica and obtain feedback on some recent work that we did on nonlinear stability analysis of patterns.

A paradigmatic model that governs monolayer self-assembly was constructed a few years back by Wei Lu (Michigan) and Zhigang Suo. Apart from obtaining several physical insights they also conducted a linear stability analysis of their model. Borrowing technqiues from the nonlinear physics community, our work presents nonlinear stability analysis i.e. the initial state is no longer homogeneous and stable states beyond the transition are calculated. This allows a detailed construction of stability maps for various patterns without extensive numerical calculations.

This work is currently under review and I am attaching a pre-print with this post. Any comments and suggestions would be well-appreciated.