research

When a block of an elastomer is bent, the compressed surface may form a crease. This paper analyzes the critical condition for creasing by comparing the elastic energy in a creased body and that in a smooth body. This difference in energy is expressed by a scaling relation. Critical conditions for creasing are determined for elastomers subject to general loads and gels swelling under constraint. The theoretical results are compared with existing experimental observations.

Dear all,

     Many numerical implementation of plasticity model uses spectral decomposition to represent the Cauchy stress, elastic strain,  such that stress update algorithm is written in the principal directions. As a result, I wonder what makes it benefical to write the stress update algorithm in spectral form? 

 Thanks,

WaiChing Sun

  The difference to the common model used is the f,g terms. The 3D FEM formulation has been derived and a new fortran program is written. The derivative matrix is symmetric. But the calculation result does not converge. I have tried every means to get a converging result. But it doesn't work, the residual norm always increases.

Dear friends,

I want to share our recent research work on NiAl nanowire, which is published in Nanotechnology, IOP publishing. The abstract of the paper is given below. Further details can be found at "Vijay Kumar Sutrakar et al 2009 Nanotechnology 20 295705 (9pp)   doi: 10.1088/0957-4484/20/29/295705"

Immersed in an ionic solution, a network of polyelectrolyte polymers imbibes the solution and swells, resulting in a polyelectrolyte gel. The swelling is reversible, and is regulated by ionic concentrations, mechanical forces, and electric potentials. This paper develops a field theory to couple large deformation and electrochemistry. A specific material model is described, including the effects of stretching the network, mixing the polymers with the solvent and ions, and polarizing the gel.