research

In this paper we formulate the problem of elastodynamic transformation cloaking for Kirchhoff-Love plates and elastic plates with both in-plane and out-of-plane displacements. A cloaking transformation maps the boundary-value problem of an isotropic and homogeneous elastic plate (virtual problem) to that of an anisotropic and inhomogeneous elastic plate with a hole surrounded by a cloak that is to be designed (physical problem). For Kirchhoff-Love plates, the governing equation of the virtual plate is transformed to that of the physical plate up to an unknown scalar field.

Dear iMechanicians,

I hope some of you find of interest our latest Acta Mat. paper. We show that the concept of "beneficial traps" can enlarge by an order of magnitude the range of "safe loading frequencies" at which hydrogen embrittlement is not observed. 

Analysis of the influence of microstructural traps on hydrogen assisted fatigue

Rebeca Fernández-Sousa, Covadonga Betegón, Emilio Martínez-Pañeda

Acta Materialia 199, 253-265 (2020). Link

By Yu Zhou and Lihua Jin

Journal: International Journal of Fracture

Abstract: A simple nonlocal field theory of peridynamic type is applied to model brittle fracture. The kinetic relation for the crack tip velocity given by Linear Elastic Fracture Mechanics (LEFM) is recovered directly from the nonlocal dynamics, this is seen both theoretically and in simulations. An explicit formula for the change of internal energy inside a neighborhood enclosing the crack tip is found for the nonlocal model and applied to LEFM.

Usually, roughness destroys adhesion and this is one of the reasons why the "adhesion paradox", i.e. a "sticky Universe", is not real. However, at least with some special type of roughness, there is even the case of adhesion enhancement, as it was shown clearly by Guduru, who considered the contact between a sphere and a wavy axisymmetric single scale roughness, in the limit of short-range adhesion (JKR limit).

EML Webinar on 9 September 2020 will be given by Prof. Rob Ritchie, University of California, Berkeley, Discussion leader: Nanshu Lu, University of Texas at Austin.

Title: Damage-Tolerance in Engineering and Biological Materials

Time: 7 am California, 10 am Boston, 3 pm London, 10 pm Beijing on 9 September 2020

https://doi.org/10.1016/j.ijplas.2020.102850

Abstract

The Biofilm Matrix - A Living Engineering Material

Chenxi Zhai, Haoyuan Shi, Tianjiao Li, Liming Zhao, Jingjie Yeo

J² Lab for Engineering Living Materials, Sibley School of Mechanical and Aerospace Engineering, Cornell University

Introduction