Elastocapillary cleaning of twisted bilayer graphene interfaces
Dear iMechanicians, I would like to share our recent work on a drop confined by two adhesive graphene sheets (as illustrated below).
research
Variational principles for nonlinear pde systems via duality
Amit Acharya
A formal methodology for developing variational principles corresponding to a given nonlinear
pde system is discussed. The scheme is demonstrated in the context of the incompressible
Navier-Stokes equations, systems of first-order conservation laws, and systems of Hamilton-
Jacobi equations.
An action for nonlinear dislocation dynamics
Amit Acharya
To appear in J. Mech. Phys Solids
Amit Acharya
An action functional is developed for nonlinear dislocation dynamics. This serves as a fi rst step
towards the application of eff ective field theory in physics to evaluate its potential in obtaining
a macroscopic description of dislocation dynamics describing the plasticity of crystalline solids.
Connections arise between the continuum mechanics and material science of defects in solids,
eff ective field theory techniques in physics, and fracton tensor gauge theories.
The scheme that emerges from this work for generating a variational principle for a nonlinear
pde system is general, as is demonstrated by doing so for nonlinear elastostatics involving a stress
response function that is not necessarily hyperelastic.
Mechanotropism of single cells adhering to elastic substrates subject to exogenous forces
Adherent cells are able to actively generate internal forces, channeled by cytoskeletal protein filaments and transmitted through transmembrane receptors to the surrounding environment by means of focal adhesions.
Uniaxial stretch-release of rubber-plastic bilayers: strain dependent transition to stable helices, rolls, saddles, and tubes
Polymeric plastics deform irreversibly (i.e., inelastically) whereas rubbers deform reversibly, i.e., elastically.
Thus, uniaxially stretching a rubber-plastic bilayer composite beyond its yield point can create an elastic strain mismatch between the two layers. Upon release, the bilayer may then bend out-of-plane.
Bulky auxeticity, tensile buckling and deck-of-cards kinematics emerging from structured continua
Complex mechanical behaviours are generally met in macroscopically homogeneous media as effects of inelastic responses or as results of unconventional material properties, which are postulated or due to structural systems at the meso/micro-scale.
Examples are strain localization due to plasticity or damage and metamaterials exhibiting negative Poisson’s ratios resulting from special porous, eventually buckling, sub-structures.
Journal Club for August 2021 - Electromechanics of Polyelectrolytes
Meredith Silberstein and Max Tepermeister
Cornell University, Sibley School of Mechanical and Aerospace Engineering
Molecular‑level investigation on the spallation of polyurea
Our paper "Molecular‑level investigation on the spallation of polyurea" is freely available from this link: https://rdcu.be/cqkbG
We used molecular dynamics (MD) simulations to investigate the nanoscale mechanism associated with the spallation of polyurea, which allowed us to test some assumptions commonly made in the interpretation of similar experiments on the macroscale.
Efficient Constant Strain Tetrahedron Shape Functions
Dear researchers,
Hi all,
I am pleased to post my following publication:
Study on Dynamic Detection of Reinforced Concrete Bridge Damage by Finite Element Model Updating
How can solid ice be tested in laboratory environment (mechanical testing)?
Below is a blog post based on equipment that we have built for testing solid ice samples. We designed an ADMET biaxial testing system (eXpert 8600 series) in collaboration with the Rock and Ice Deformation Laboratory (RIDL) at Woods Hole Oceanograhic Institution (WHOI).
Test Application