bending
Improved formulas of extensional and bending stiffnesses of rectangular nanorods
Improved formulas of extensional and bending stiffnesses of isotropic rectangular nanorods are derived. These formulas reduce to the existing widely used formulas for a special choice of material parameters, i.e., when the surface Poisson's ratio and the bulk Poisson's ratio match thus highlighting the limitation of the existing formulas.
A variant of Irving-Kirkwood-Noll formulation for one-dimensional nanostructures
We present a one-dimensional variant of the Irving-Kirkwood-Noll procedure to derive microscopic expressions of internal contact force and moment in one-dimensional nanostructures. We show that these expressions must contain both the potential and kinetic parts: just the potential part does not yield meaningful continuum results. We further specialize these expressions for helically repeating one-dimensional nanostructures for their extension, torsion and bending deformation. As the Irving-Kirkwood-Noll procedure does not yield expressions of stiffnesses, we resort to a thermodynamic equilibrium approach to first obtain the Helmholtz free energy of the supercell of helically repeating nanostructures. We then obtain expressions of axial force, twisting moment, bending moment and the associated stiffnesses by taking the first and second derivatives of the Helmholtz free energy with respect to conjugate strain measures. The derived expressions are used in finite temperature molecular dynamics simulation to study extension, torsion and bending of single-walled carbon nanotubes and their buckling.
The article will soon appear in the Mathematics and Mechanics of Solids. The same can be accessed at the following link: https://www.researchgate.net/publication/337873624_Microscopic_definiti…
Call for Abstracts: Numisheet 2020 mini symposium on “Challenges and Opportunities in Forming Aluminum”
The NUMISHEET conference series is the most significant international conference on the area of the numerical simulation of sheet metal forming processes. Within Numisheet 2020, we are organizing a mini symposium on “Challenges and Opportunities in Forming Aluminum”.
Bending of Multilayer van der Waals Materials
Dear colleagues, I'd like to share our recent work on blister testing of multilayer 2D materials that gives a direct measurement of Young's modulus and bending rigidity of a multilayer (~10-70 layers). Materials involved include graphene, MoS2, and hBN.
You may access the pdf through Phys. Rev. Lett. 123, 116101 or Researchgate.
Visualizing bending and torsional deformation using experiment
This video contains an experimental demonstration of a simple bending and torsion and further speculate the nature of stresses induced by the respective loading scenarios
OVERHEAD ELECTRICAL CONDUCTORS IN BENDING : A SEMI-CONTINUOUS MODEL
As indicated in the review by Cardou & Jolicoeur (1997), and depending on the application, a helically stranded system may be modelled using a semi-continuous approach whereby each layer is replaced by a continuous helical orthotropic material. For those able to read Russian, this approach is presented in a paper by Danilin & Al. specifically oriented towards Overhead Electrical Conductor mechanics: “Modelling of Deformation of Wire Spiral Structures” published in the PNRPU Mechanics Bulletin (2015, No 4, pp. 72-93).
Graphene is softer to bend when stretched and bent and harder to stretch when bent and moderately stretched
In the attached paper, we have shown that concomitant bending and stretching, whatever their value, concur to make bending stiffness decrease; moreover, concomitant bending and stretching make the stretching stiffness (or the Young modulus) increase until the applied forces reach a threshold value, then they make it decrease. Said differently, graphene is softer to bend when stretched and bent and harder to stretch when bent and moderately stretched.
Rising Beyond Elastocapillarity
Douglas P. Holmes, P.-T. Brun, Anupam Pandey, and Suzie Protière, Soft Matter, 12, 4886-4890, (2016).