research

https://doi.org/10.1007/978-3-319-50257-1_83-1 The second volume of the Handbook of Materials Modeling is now online: We reviewed the development of new empirical molecular dynamics forcefields, novel methods of generating aerogels’ percolated backbones, and compelling algorithms for characterizing their structural, mechanical, and thermal properties that have resulted in unprecedented insights into silica aerogels.

In 2007 I wrote a question in Imechanica, IS THERE NO PULL-OFF FOR ADHESIVE FRACTAL SURFACES?

Clearly, in 2007 this question was too hard to answer.  I pointed there that Fuller and Tabor 1975 asperity theory predicted a weird limit for a true fractal surface, that of no stickiness for any fractal dimension or amplitude, in the limit.

Lattice models are popular methods for simulating deformation of solids by discretizing continuum structures into spring networks. Despite the simplicity and efficiency, most lattice models only rigorously converge to continuum models for lattices with regular shapes. Here, we derive a lattice model for neo-Hookean solids directly from finite element methods (FEM). The proposed lattice model can handle complicated geometries and tune the material compressibility without significantly increasing the complexity of the model.

Two PhD positions are available at the University of Southampton in the areas of:

(1) Computational modelling of complex structures and structured materials - especially those fabricated using additive manufacturing,

https://jobs.soton.ac.uk/Vacancy.aspx?ref=1037118AK

and 

(2) Elastic and acoustic metamaterials using additive manufacturing.

https://jobs.soton.ac.uk/Vacancy.aspx?ref=1037018AK

I am looking to recruit a highly motivated and independent postdoctoral researcher to study, via the development of new computational techniques, various scientific issues surrounding phononic topological insulators.  The position is available for a 1-year duration, with possible extension to future years depending on the availability of funding.  

Requirements for the position include:

1.  A strong background in computational solid mechanics, and in particular topology optimization techniques (i.e. level set-based)

https://doi.org/10.1039/C8CP01191E We investigate the effect of varying carbon nanotube (CNT) size on the desalination performance through slit confinements formed by horizontally aligned CNTs stacked on top of one another. By increasing the CNT size, the results obtained from this study indicate a corresponding increase in the water flow rate, accompanied by a slight reduction in salt rejection performance.

(in Journal of Elasticity)

A continuum mechanical framework is developed for determining a) the class of stress-free deformed shapes and corresponding director distributions on the undeformed configuration of a nematic glass membrane that has a prescribed spontaneous stretch field and b) the class of undeformed configurations and corresponding director distributions on it resulting in a stress-free given deformed shape of a nematic glass sheet with a prescribed spontaneous stretch field. The proposed solution rests on an understanding of how the Lagrangian dyad of a deformation of a membrane maps into the Euleriandyad in three dimensional ambient space. Interesting connections between these practical questions of design and the mathematical theory of isometric embeddings of manifolds, deformations between two prescribed Riemannian manifolds, and the slip-line theory of plasticity are pointed out.

(To appear in Journal of Elasticity).

Abstract: Shear banding is widely observed in natural fault zones as well as in laboratory experiments on granular materials. Understanding the dynamics of strain localization under different loading conditions is essential for quantifying strength evolution of fault gouge and energy partitioning during earthquakes and characterizing rheological transitions and fault zone structure changes. To that end, we develop a physics-based continuum model for strain localization in sheared granular materials.

On the Role of the Plaque Porous Structure in Mussel Adhesion: Implications for Adhesion Control Using Bulk Patterning

Ahmed Ghareeb and Ahmed Elbanna -- Journal of Applied Mechanics (2018)