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Mike Ciavarella's blog

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Forget 3D printing....

In the last number of ....Nature an article which sounds like promising a new revolution in 3D printing.

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review paper: The role of adhesion in contact mechanics

Journal of The Royal Society Interface 16(151), February 2019.    DOI: 10.1098/rsif.2018.0738

Michele Ciavarella Junki Joe Junki Joe Antonio Papangelo James Richard Barber

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Stress-life vs strain life approaches in efatigue.com ?

dear collegue

 have you ever tried to compare the stress-life approach with the strain-life?

 I was experimenting with some students using the website https://www.efatigue.com/with normal notches and normal materials included in the web site database.

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Is Tribology Approaching Its Golden Age? Grand Challenges in Engineering Education and Tribological Research

An interesting paper by VL Popov which suggests many problems of tribology are still very far from being remotely solved.  Despite the very detailed theories for example on rough contact using fractal surfaces on which we have debated mainly academically , there is not a single theory for any quantitative prediction of friction coefficient which can vary by 1 order of magnitude and its dependence on many variables, let alone wear coefficient which can vary up to 7 orders of magnitude.  What is left to do, other than measure?   Is tribology bound to be in practice just an experimental area? 

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Questions to experts in Variable Amplitude Loading in Fatigue of metals

As a newcomer in this field, I try to pose some questions to the experts in Variable Amplitude Loading fatigue. The questions are probably trivial, but I don't find any reply in the literature, particularly on the arbitrary choice of frequency cutoff in the spectrum loading, and on the distinction  between cracked and uncracked structures. See attach and please respond if you can, even directly on email at mciava@poliba.it

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new ranking of highly cited researchers

In the ranking of the Highly Cited Researcher by Clarivate Analytics for 2018 that in Italy includes 95 scientists (of course in all disciplines from Medicine to Engineering) for the first time we have 2 working in my region, Puglia, in the new Cross-Field field.

One in medical field Logroscino Giancarlo (Policlinico di Bari, Associate Professor) University of Bari

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On stickiness criteria for multiscale random rough contacts

We have just submitted a paper which solves a problem that I have been struggling to solve for many years.

Any comments are welcome to improve, while the paper goes the standard review process in the journal we submitted it.

 

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fatigue: overstressing and understressing

 

While teaching some students from old textbooks, I found reference to "understressing and overstressing" as producing effects into fatigue limits.    Looking at classical papers like  W SCHUTZ, A HISTORY OF FATIGUE Engineering Fracture Mechanics Vol. 54, No. 2, pp. 263-300, 1996, he says that the theory of understressing was largely a mistake due to statistically poor testing.  However, I see some chinese papers still talk of understressing, see below.

 

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Jacob Israelashvili passed away

  I was about to write to dr Jacob Israelashvili because I was working on some adhesion problem and was wondering how to possibly send it to PNAS, but I read he passed away for cancer....   I had received some email few months ago about another question on his famous SFA and how to give some results useful for his company, he responded from the hospital evidently... that "nothing worries me"... What an example of strength.

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are fractal surfaces adhesive? a new attempt on JMPS

In 2007 I wrote a question in Imechanica, IS THERE NO PULL-OFF FOR ADHESIVE FRACTAL SURFACES?

Clearly, in 2007 this question was too hard to answer.  I pointed there that Fuller and Tabor 1975 asperity theory predicted a weird limit for a true fractal surface, that of no stickiness for any fractal dimension or amplitude, in the limit.

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Famous Morandi Genoa bridge collapses

There has been much discussion after the very sad collapse of a well known bridge in Genoa, designed by a famous bridge engineer Riccardo Morandi, more than 50 years ago.

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several phd positions at the Dept Mech Engineering Politecnico di BARI

Soon several phd positions including 1 reserved to non-italian citizens at Politecnico department of Mechanical engineering.

Various options for research themes are available, also including solid mechanics, fatigue, adhesion and contact mechanics.

See attachment or write for details at mciava AT poliba.it

Application expires on Sept.12, but please contact us for details asap !

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a new book "Contact Mechanics" from JR Barber

I am pleased to suggest a very interesting new book from prof JR Barber of UMich, a leading scientist in the field of contact mechanics.

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2 dead, gunman at large in Central Michigan University shooting

Here.  The question of safety especially in US campuses, is serious.

Very terrible news.

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Knowing the strength of adhesion

Knowing the strength of adhesion

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National TV program on Politecnico di BARI and its successes

See a national broadcast on Politecnico di BARI and the region Puglia, with its successes, including the worldwide success of Diesel common rail technology, the GE centre on Addittive Manufacturing and Cold Spray, and others.

 

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UK university staff strike over pension changes – live

See here.  Or here In comparison, our "italian strike" where we only omit 1 session of exams was much less dramatic. 

It will be interesting to follow the UK strike, because I would be surprised if so many academics let such significant part of salary be reduced.

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a "contact sport" between academics

Recently, there was a big competition announced for rough elastic adhesive contact --- by Martin Muser as organizer.  This was published in Tribology Letter, involved the effort of many groups in the world, and finally got even a commentary in Science by Rob Carpick.

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