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Variational principles for nonlinear pde systems via duality

Submitted by Amit Acharya on

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

Submitted by Amit Acharya on

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

Submitted by Luca-Deseri on

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

Submitted by Luca-Deseri on

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

Submitted by Luca-Deseri on

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.

Molecular‑level investigation on the spallation of polyurea

Submitted by Nuwan Dewapriya on

 

 

 

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

Submitted by mohammedlamine on

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)?

Submitted by Deniz Yalcin on

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

My Scientific New Paper

Submitted by mohammedlamine on

Hi All,

My New Scientific Paper is :

Structural Probabilistic Health Monitoring of a Potentially Damaged Bridge

Mohammed Lamine MOUSSAOUI , Mohamed CHABAAT , Abderrahmane KIBBOUA

International Journal of Structural and Civil Engineering Research

Volume 10, No. 3, pp. 119-122, 2021

Doi: https://doi.org/10.18178/ijscer.10.3.119-122