Skip to main content

research

Mechanisms of compressive deformation and failure of porous bulk metallic glasses

Submitted by Parag Tandaiya on

Porous Bulk Metallic Glasses have been invented by researchers to mitigate catastrophic failure in monolithic Bulk Metallic Glasses which are susceptible to intense strain localization into shear bands.

Nonlocal Micromechanics of Composites of both Random and Periodic Structures (Background, Opportunities and Prospects)

Submitted by Valeriy Buryachenko on

An extended abstract dedicated to nonlocal (in the sense of either Eringen or Silling) micromechanics is attached. It can’t be considered as a review in any sense. It is just a personal vision on a new area of micromechanics, in particularly based on the author’s publications (references on hundreds related papers can be found in the referred publications). The style of the abstract is plausible rather than rigorous that willfully used by the author just for initiation of discussions in the new prospective area of micromechanics.

A variant of Irving-Kirkwood-Noll formulation for one-dimensional nanostructures

Submitted by Ajeet Kumar on

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…

Post-Doctoral Position in Modeling of Thermal Transport in Crystalline Solids

Submitted by AnterEl-Azab on

The Materials Theory Group at the School of Materials Engineering of Purdue University has a post-doctoral opening in the area of modeling of thermal transport in crystalline solids. The postdoc will use Boltzmann Transport Equation approach to investigate the phonon and electron thermal transport in crystalline solids with defects. Applicants with closely related theory background in physics, materials science, mechanical engineering, or other majors are encouraged to apply. The ideal candidate is one who is strongly interested in the fundamental concepts of thermal transport and related computational modeling, and must have excellent programming skills. To apply, please send a curriculum vita with list of publications and the names and contact information of two references to Professor Anter El-Azab (aelazab [at] purdue.edu). The cover letter should explain the relevance of the applicant background to the postdoc research topic above. This position is part of the DOE funded Energy Frontiers Research Center for Thermal Energy Transport under Irradiation (TETI), and the postdoc is expected to collaborate with a large team of theorists and experimentalists. The position is available now and will remain open until filled.

Plane stress Abaqus UMAT

Submitted by lefteris tsivolas on
Choose a channel featured in the header of iMechanica

Hello everyone,

I have created a UMAT code for J2 elasto-plasticity with isotropic hardening for 3D solid elements.

At this point I would like to support also plane stress shell elements. What changes in the code are

suggested? The already implemented code, takes as input the strain tensor at time tn and the strain

increment tensor and updates the stress at time tn+1 and calculates the material Jacobian and 

achieve quadratic convergence. The stress and strain tensors are manipulated as 6x1 vectors and the 

Novel Metamaterials based on Triply Periodic Minimal Surfaces

Submitted by Rashid K. Abu Al-Rub on

Recently, there has been a growing interest in investigating the multi-functional properties of novel types of metamaterials, metastructures, and metacomposites based on triply periodic minimal surfaces (TPMS). TPMS have been discovered more than 160 years ago and thanks to additive manufacturing (3D printing) they become reality only recently and opend the doors for several applications.

Structures loaded with a force acting along a fixed straight line, or the “Reut’s column problem”

Submitted by Davide Bigoni on

How to provide a structure with a force lying on a fixed line?
We provide the answer to this question in our paper: Bigoni and Misseroni (2019) Structures loaded with a force acting along a fixed straight line, or the “Reut’s column problem”.
Journal of the Mechanics and Physics of Solids.
Enjoy watching our video below (would you have trouble playing video on YouTube, click here to watch it).