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Cancelling the effect of sharp notches or cracks with graded elastic modulus materials

Dear colleague

   I wonder if you could be interested in this idea of "Cancelling the effect of sharp notches or cracks with graded elastic modulus materials", particularly if you know who could help doing some experiments. Thanks for any comment, since this is a preprint it would be useful to discuss to make improvements.    RegardsMike    Cancelling the effect of sharp notches or cracks with graded elastic modulus materials

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Friction for a sliding adhesive viscoelastic cylinder: Effect of Maugis parameter

Prediction of friction is one of the nigthmares of tribologists!   For elastomers, friction may be due to shear stresses or to dissipation and adhesion hysteresis.  Here we consider the two effects in rolling/ sliding a viscoelastic cylinder. We find that at low speeds the numerical bem results confirm Persson/Brener theory for crack propagation at large Tabor parameter.

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apparent paradox: for a sliding flat punch on a viscoelastic halfspace, friction is zero or not?

dear Imechanica friends here is an apparent paradox: for a sliding flat punch on a viscoelastic halfspace, friction is zero or not?  Certainly there seems to be viscoelastic dissipation, but the pressure is also normal to dispacements, so am I missing something obvious here?

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2023 career elsevier top scientists rankings --- congratulation to the Harvard professors

I have extracted in attachment the top scientists according to the Elsevier October 2023 data-update for "Updated science-wide author databases of standardized citation indicators", see https://elsevier.digitalcommonsdata.com/datasets/btchxktzyw/6

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On the Shrimali and Lopez-Pamies theory on viscoelastic fracture mechanics

dear collegues

 

   I have been attracted recently by a theory from Shrimali and Lopez-Pamies which is based on experimental evidence obtained from Suo's group in Harvard in 2012 in a (limited, but significant) set of experiments on rubber.   The theory assumes that the stretch to nucleating a crack is constant and independent on stretch rate.  The theory is then built on that, to predict the increase of fracture energy with rate.

 

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Prof. Huajian Gao elected FRS

Eighty outstanding researchers, innovators and communicators from around the world have been elected as the newest Fellows of the Royal Society, the UK’s national academy of sciences and the oldest science academy in continuous existence.

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A few PhD positions are available at PoliBA (Italy) in adhesion regulated by microvibrations

Call for PhD student grants and applications

 

Location: Polytechnic University of Bari, Department of Mechanics Mathematics and Management (DMMM), Via Orabona 4 - 70125 Bari – Italy

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Fretting fatigue --- is there really an important effect of friction coefficient??

dear Colleagues

In writing a review of models on fretting fatigue, I am looking at the effect of friction coefficient.   Obviously, if friction is zero there is no fretting fatigue!   This goes without saying.

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A very simple solution to the rolling contact problem will falling friction

In rail-wheel contact modelling, there is a huge industrial interest to model accurately rolling contact of hard bodies with friction for predicting fatigue, squeal, noise, vehicle dynamics.     In the literature, the case of Carter 1926 has been extended with numerical codes known as FASTSIM and CONTACT which are based on algorithms by JJ Kalker.     However, there is a serious problem to model falling rate-dependent friction, which gives unexpected instabilities and unclear solutions.

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A comment on a hybrid asperity-Persson friction rubber theory by A Emami, S Khaleghian and S Taheri. Friction 9(6): 1707--1725 (2021)

dear collegues, I may be interested to share your views on an "asperity theory" modified Persson's rubber friction contact mechanics theory which I find not clearly motivated and seems to lead to erroneous conclusions ---- but I am also unable to reproduce the results claimed by the authors. The preprint is here, and the original paper attached: https://www.researchgate.net/publication/359392510

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Improved Muller approximate solution of the pull-off of a sphere from a viscoelastic substrate

M. Ciavarella (2021) Improved Muller approximate solution of the pull-off of a sphere from a viscoelastic substrate, Journal of Adhesion Science and Technology, DOI: 10.1080/01694243.2021.1882766

See also in attach the PDF.

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Ciavarella-McMeeking. Crack propagation at the interface between viscoelastic and elastic materials

Crack propagation at the interface between viscoelastic and elastic materials

M.Ciavarella, R.McMeeking

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On the Afferrante-Carbone theory of ultratough peeling

I attach a preprint of a note on the elegant and interesting and simple theory by Afferrante and Carbone on ultratough peeling of an elastic tape from a viscoelastic substrate.   Any comment is most welcome.   Regards, MC

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In the 100 000 top scientists there is decline of USA, and a jump of China and India

Not everyone has noticed, also from our previous studies including a letter to Nature,  that in the list of 100 000 most cited scientists by Ioannides et al. recently published in PLOS Biology, comparing the career database (1996-2017) with that of 2017, composed of around 2% of Italians, all the states we analysed except for Italy and China and India have suffered a decline in the number of researchers present in the 2017 data set compared to even substantial career data (Japan –20% nationally ).

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Analytical Models for Fatigue Life Prediction of Metals in the Stress-Life Approach -- phd thesis by Pietro D’Antuono

dear collegues

  I'd be very grateful if you could have a look, if not a deep reading, at the phd thesis of my last student, playing on classical results on uniaxial fatigue, but with a view of simple, unified perspective on constant and varying amplitude fatigue.  We made large use of e-fatigue.com web site and the data in there.
 Thanks in advance for any remark.  The final thesis will be submitted in few weeks time.

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electroadhesion of rough surfaces, with application to touch screen technology

Just submitted a paper on electroadhesion of rough surfaces, greatly simplifying the recent theory of the great Bo Persson , with hot application to touch screens :  see here

Comments welcome.

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The false myth of the rise in Italian self-citations, and the impressively positive effect of bibliometric evaluations on the increase of the impact of Italian research

Title: The false myth of the rise in self-citations, and the impressively positive effect of bibliometric evaluations on the increase of the impact of Italian research

Authors: Pietro D'Antuono and Michele Ciavarella

Categories: physics.soc-ph math.ST stat.TH   Comments: 20 pages, 8 figures, 10 tables, in English and inItalian  License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/

 https://arxiv.org/abs/1910.02948

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