Mike Ciavarella's blog

We provide a very simple result for a problem which has been often neglected (variable amplitude loading) in academia, but which is of paramount importance in real engineering situations, where fatigue is almost never "constant amplitude".

We found few cases where we could check this extremely simple result, but it worked very well.  We would welcome further verifications.

The paper is in press here.

See here.

The top italian engineer Davide Bigoni gets his 4th cover in Proc. Roy. Soc. A in just 18 months 

See here.

Maybe because I am proud of Betti's theorem being italian, I am curious about this big emphasys on systems violating it.  They may "open avenues for energy absorption, conversion and harvesting, soft robotics, prosthetics and optomechanics".... ?  I'd be curious to hear some comments.   Anyway, the last author Andrea Alu is anyway italian like Betti.

Abstract Submission Extended to March 1st 2017

More information

Article in Journal of The Royal Society Interface · January 2017DOI: 10.1098/rsif.2016.0996

Dear Colleague,

We are pleased to announce the 10th European Solid Mechanics Conference – ESMC 2018, which will be held in Bologna (Italy) during July 2-6, 2018. 
The Conference is organized by the University of Trento and the University of Bologna.

    The stress concentration induced by fretting fatigue was studied with a simple "Crack Analogue" model (CA) by the MIT group of Suresh in the late 1990's, which was then "improved" by the present author to take into account simply both contact loads and bulk stresses loads, and even the case of finite stress concentration in the so-called "Crack Like Notch Analogue" (CLNA) model.

 International Journal of Mechanical Sciences

Available online 28 December 2016

In Press, Accepted Manuscript — Note to users

We have organized a Lorentz Workshop with 60 selected partecipants leading scientists in tribology and contact mechanics mainly from Europe.

Attached a program.   Or see the web site

Micro/Nanoscale Models for Tribology (μ/n-Tribo-Models) 

Vladislav Yastrebov (co-organizer)

Lucia Nicola (co-organizer)

Annalisa Fasolino (co-organizer)

Michele Ciavarella (co-organizer)

Julien Scheibert (co-organizer)

Journal of the Mechanics and Physics of Solids

Available online 4 August 2015

In Press, Accepted Manuscript — Note to user

Abstract

Jim Barber and I just got accepted this paper in JMPS, and it is also already available on Arxiv.  We found a remarkably simple closed form solution for adhesion on orthotropic materials in the planes of symmetry.  This shows adhesion can increase significantly due to anisotropy, namely the JKR solution continues to hold in the sense of mean elastic modulus, but the prefactor can grow without limit. We expect applications in crystals indentation, but also in locomotion in biological world.

Would you believe this story?

To me, that metal - on - metal had large friction, especially with the newest designs, it was clear from the old Sir Charnley studies in Leeds in 1950s published in his gold book. 

Anyway, when I looked at ceramic on ceramic joints, I also found evidence of increased friction.  Maybe ceramic debris is less toxic?

Please comment.  What can we do outside USA to improve the situation?

Michele Ciavarella