membranes

Dear friends, I want to share our recent work on the shape characteristics of 2D crystal blisters. Micro- and nano-sized blisters can form spontaneously when two-dimensional (2D) crystals are transferred onto substrates because liquid molecules that are initially adsorbed on 2D material and substrate surfaces can be squeezed and trapped by interfacial forces. On the one hand, blisters are undesirable in 2D material devices as they impede charge/photon/phonon transport across the interface, so various means were developed to eliminate interfacial blisters. On the other hand, m

Two fully-funded postdoctoral positions in computational mechanics of materials and structures are available in the groups of Milan Jirásek (https://mech.fsv.cvut.cz/~milan) and Jan Zeman (https://openmechanics.fsv.cvut.cz/people/jan-zeman). Full description of the openings is available at https://euraxess.ec.europa.eu/jobs/573988, the call closes on 5 December 2020.

Wrinkles are commonly observed in uniaxially stretched rectangular sheets with clamped-clamped boundaries, and can disappear upon excess stretching. Here we explore this wrinkling and restabilization behavior both analytically and numerically. We find that Poisson’s ratio plays a crucial role in the wrinkling and restabilization behavior. Smaller Poisson’s ratio makes later onset of wrinkling, lower amplitude and earlier disappearance of wrinkles.

Wrinkles commonly occur in uniaxially stretched rectangular hyperelastic membranes with clamped-clamped boundaries, and can vanish upon excess stretching. Here we develop a modeling and resolution framework to solve this complex instability problem with highly geometric and material nonlinearities. We extend the nonlinear Foppl-von Karman thin plate model to finite membrane strain regime for various compressible and incompressible hyperelastic materials.

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.

http://orbilu.uni.lu/handle/10993/16438 http://orbilu.uni.lu/bitstream/10993/16438/1/2014_NURBSbasedExplicit_Me…