research

We present a geometric theory of nonlinear solids with distributed dislocations. In this theory the material manifold - where the body is stress free - is a Weitzenbock manifold, i.e. a manifold with a flat affine connection with torsion but vanishing non-metricity. Torsion of the material manifold is identified with the dislocation density tensor of nonlinear dislocation mechanics. Using Cartan's moving frames we construct the material manifold for several examples of bodies with distributed dislocations. We also present non-trivial examples of zero-stress dislocation distributions.

ACS Nano, DOI: 10.1021/nn204476h

I have formulated a shear-lag model for calculating the variation of stress along carbon nanohorns (CNHs), which are conical shaped wrapped carbon sheets, embedded in an epoxy matrix under axial loading.  I found that the stress distribution along the length of CNHs depends on the cone angle of these structures and maximum normal axial stress has a smaller value in CNHs compared to a carbon nanotube (CNT) with same cross-section as of the CNH's tip.  Furthermore, I read an article stating that synthesis of CNHs are easier compared to CNTs.  However, the only article I could f

Forthcoming papers of International Journal of Applied Mechanics (IJAM) Vol.4 No.1:

1.     “A SPECTRAL/HP FINITE ELEMENT FORMULATION FOR VISCOELASTIC BEAMS BASED ON A HIGH-ORDER BEAM THEORY”,  V. P. VALLALA, G. S. PAYETTE AND J. N. REDDY, (TEXAS A&M UNIVERSITY, USA).

Consisting of alternating swelling and nonswelling polymeric layers (SLs and NLs), lamellar gels are 1D photonic crystals with tunable optical properties.  The lamellar structure induces a constraint between the SLs and the NLs, resulting in an anisotropic swelling behavior coupled with deformation.