research

H. Hou, E. Simsek, T. Ma, N.S. Johnson, S. Qian, C. Cissé, D. Stasak, N. Al Hasan, L. Zhou, Y. Hwang, R. Radermacher, V.I. Levitas, M.J. Kramer, M. Asle Zaeem, A.P. Stebner, R.T. Ott, J. Cui, I. Takeuchi. Fatigue-resistant high-performance elastocaloric materials made by additive manufacturing. Science 366 (6469) (2019) 1116-1121.

Abstract

Adhesive contact of the Hertzian indenter with an incompressible elastic substrate bi-directionally stretched along the indenter principal planes of curvature is considered in the Johnson–Kendall–Roberts theoretical framework. An approximate model is constructed by examining energy release rate conditions only on the edges of the minor and major axes of the contact ellipse. The effect of weak coupling between fracture modes I and II is introduced using a phenomenological mode-mixity function.

I am creating this post to get some inputs on deriving the analytical solution to the 3D nonlinear elastic wave equation.

Recently, I guest-edited a special issue of the journal Entropy on Unified Mechanics Theory and related topics. All published papers are available for free download from the link below.

https://www.mdpi.com/journal/entropy/special_issues/fatigue

I hope that some of you will find this work interesting. We show that early cracking occurs in slow strain rate tensile testing (SSRT), which compromises the capabilities of this popular experiment for measuring hydrogen embrittlement susceptibility.

On the suitability of slow strain rate tensile testing for assessing hydrogen embrittlement susceptibility

E. Martínez-Pañeda, Z. D. Harris, S. Fuentes-Alonso, J. R. Scully, J. T. Burns

Corrosion Science 163, 108291 (2020)

In Journal of the Royal Society Interface https://royalsocietypublishing.org/doi/10.1098/rsif.2018.0738

A few years ago, we observed Wallner Lines on the fracture surface of a brittle Bulk Metallic Glass and explained the process of formation of nanocorrugations on the fracture surface.

We published our research in Acta Materialia in the paper: 'Wallner lines, crack velocity and mechanisms of fracture in a brittle bulk metallic glass'.

A few years ago we published a paper in Acta Materialia elucidating the mechanism and length scales in the ductile fracture of bulk metallic glass through experiments and finite element simulations.

The link to the paper is here: 'On the mechanism and the length scales involved in the ductile fracture of a bulk metallic glass'.

I hope you enjoy reading the paper and find it useful in your research.

There is a shortage of literature on mode III fracture behaviour of bulk metallic glasses.

In our following research paper published in Acta Materialia, we report our experiments and three-dimensional elasto-plastic finite element simulations of tension-torsion loading on notched ductile bulk metallic glass bars.

It is found that fracture toughness of this BMG is lowest in mode II among all three fracture modes.

Bulk Metallic Glasses were found to exhibit an intermediate temperature minimum in ductility. Does it also lead to an intermediate temperature minimum in fracture toughness?

Porous Bulk Metallic Glasses have been found to be mechanically superior under compressive stress states.

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.

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_definitio...