Let us consider interaction of two atoms/molecules/particles. The reference distance between them corresponds to zero interaction force and zero stored energy. The interaction passes three stages with the increase of the distance. At the first stage the force increases proportionally to the increasing distance: the linear stage. At the second stage the force-distance relationship deviates from the linear proportionality: the nonlinear stage. At the third stage the force drops with the increasing distance: the separation or failure stage.

The Congress will be held on 27 June – 2 July 2010, at the Pennsylvania State University.  The deadline for submitting abstract is 15 October 2009.

I plan to submit the attached paper on quantum mechanical definition of stress in the next few weeks. Comments and feedback are welcome. Fair amount of work has been done on stress definition in the context of classical molecular dynamics (also attracting some controversies). In contrast, there appear to be several open issues in the quantum case. Hopefully, the attached paper provides a starting point.

Several postdoc positions are available immediately at the University of Minnesota to work on the development of a variety of cutting edge multiscale methods and atomistic simulation techniques.  The work will be done in close collaboration with a group of leaders in the field including Prof. Ellad Tadmor, Prof. Richard James, Prof. Mitchell Luskin and Prof. Ryan Elliott.  For more information, visit www.multiscale.umn.edu or check out the attached announcement.

Postdoctoral position available at Princeton University to participate in a multi-disciplinary research project sponsored by the US Army Research Office (ARO/MURI) at Princeton and Harvard Universities on: Innovative Design of Multi-Functional Adaptive Structural Materials. The candidate will be involved in the Modeling of Hierarchically Porous Material Structures Optimized for Strength and Transport. The candidate must have a strong background in Finite Element Analysis (both solid and fluid), and in Topology Optimization.

Program for the 3rd International Conference on Mechanics of Biomaterials & Tissues now available at http://www.icmobt.elsevier.com/programme09.htm

Plenary and keynote speakers include:

Professor Julian Vincent, Professor of Biomimetics, Bath University, UK

-Stiffness and toughness of biological materials

I have posted the second edition of my book “Mechanics of Materials” online for free educational use. The book was reviewed and checked for accuracy by 30 faculty across the USA and was line edited by a professional editor.



The preface in the book describes the objectives and the design of the book, with details elaborated further in “Note to the Instructor”. The “Note to the Students” elaborates the many pedagogical features of the book. All these are in the file labeled “Table of content and front end material”.

Horacio Espinosa and I welcome the submission of new abstracts for a minisymposium on "Mechanics of Crystalline Nanostructures", to be held at the 2010 US National Congress on Theoretical and Applied Mechanics (USNCTAM 2010), June 27-July 2 at Penn State University. 

I am currently working on constictutive modelling of soft biological tissues, considering them as nonlinear viscoelastic materials. I am using the split form of energy density function i.e modelling separately the hyperelastc part and the visoelastic part. I am using Ogden formula for hyperelastic part and for the viscoelastic part, I am currently using the second and third invariants of stretch rate tensor.