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Journal Club for June 2020: Mechanically instructive biomaterials: a synergy of mechanics, materials and biology

 

Mechanically instructive biomaterials: a synergy of mechanics, materials and biology

Zhenwei Ma, Jianyu Li

Department of Mechanical Engineering, McGill University, Montreal, Canada

 

Mike Ciavarella's picture

Finite strains explain the non-monotonic change of contact area in soft rubber contacts loaded in torsion?

In unidirectional sliding of rubber contacts on smooth hard surface it has been found that contact shrinks largely in longitudinal directions, and generally much less in the transverse direction, and two explanations have been suggested to explain this: one is the effect of mixed mode fracture mechanics in the presence of adhesion (with mode II reducing adhesion and mode III less clear), and another uniquely based on finite strain effects even for a simple material model as neo-Hookean hyperelastic material.

Mike Ciavarella's picture

On friction effects and the conditions of failure of adhesion in punch shaped pillars and mushrooms

Carbone and Pierro (Meccanica 48, 1819--1833 (2013)) discuss that punch shaped ends give less strong adhesion than mushrooms-ended ones because of the stress singularity at the corner. In particular, they assume large friction at the interface, which leads close to the classical Linear Elastic Fracture Mechanics singularity, corresponding to the classical scaling with the flat punch shaped pillar radius for what they call mode I of failure, ruled by the so-called Kendall formula. Their calculations are valid assuming perfect bonding for both punch or mushroom shaped ends.

Kevin Turner's picture

Gordon Conference on Adhesion - Late July 2023

The Gordon Research Conference on the Science of Adhesion is this summer (23-28 July 2023).  The meeting will be held on the campus of Mount Holyoke College in western Massachusetts and will have more than 20 invited talks from world leaders in the fields of adhesion, soft matter, and materials. This is a great meeting for students and early career researchers to get connected to the community. Poster presentations are strongly encouraged from all participants, and poster abstracts can still be submitted.

Yifan Rao's picture

Size-dependent shape characteristics of 2D crystal blisters

Dear friends, I want to share our recent work on the shape characteristics of 2D crystal blisters. Micro- and nano-sized blisters can form spontaneously when two-dimensional (2D) crystals are transferred onto substrates because liquid molecules that are initially adsorbed on 2D material and substrate surfaces can be squeezed and trapped by interfacial forces. On the one hand, blisters are undesirable in 2D material devices as they impede charge/photon/phonon transport across the interface, so various means were developed to eliminate interfacial blisters. On the other hand, mechanics analys

Zhaohe Dai's picture

Peeling by pulling: In situ SEM blister test on nanoflakes

Dear iMechanicians,

I want to share our recent work published in Nano Letters on the blister test of nanoflakes. The title, abstract, and links for data are as follows:

Pull-to-Peel of Two-Dimensional Materials for the Simultaneous Determination of Elasticity and Adhesion 

Zheng Fang, Zhaohe Dai*, Bingjie Wang, Zhongzheng Tian, Chuanli Yu, Qing Chen, and Xianlong Wei*

zichen's picture

Optical and Mechanical Properties of Self-Repairing Pectin Biopolymers

Pectin’s unique physicochemical properties have been linked to a variety of reparative and regenerative processes in nature. To investigate the effect of water on pectin repair, we used a 5 mm stainless-steel uniaxial load to fracture glass phase pectin films. The fractured gel phase films were placed on a 1.5–1.8 mm thick layer of water and incubated for 8 h at room temperature and ambient humidity. There was no immersion or agitation. The repaired pectin film was subsequently assessed for its optical and mechanical properties.

Xavier Morelle's picture

Anti-icing propylene-glycol materials

Dear fellow iMechanicians,

Here is our recent paper published in EML on novel anti-icing materials based on propylene-glycol (PG) gels. This work was performed in collaboration with Xi Yao, Baohong Chen and myself while working in Zhigang Suo's lab at Harvard, and provides new solutions for anti-icing purposes (i.e. throug blankets design) without large and costly release of PG in the environment.

Anti-icing propylene glycol materials

Xi Yao, Baohong Chen, Xavier P. Morelle and Zhigang Suo*

Mike Ciavarella's picture

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.

mattia.bacca's picture

PhD opening on Mechanics of Bio-adhesion and Mechanobiology @ University of British Columbia, Vancouver (BC, Canada) - Mechanical Engineering

We are looking for a highly motivated PhD student to work on Computational Solid Mechanics, with focus on Cell Adhesion and Mechanobiology. The project is in collaboration with experimental biologists and biophysicists located at UBC and other international laboratories. It will involve the use analytical tools in Continuum Mechanics and Thermodynamics (e.g. Statistical Mechanics), and computational tools such as Finite Element Analysis. The goal will be to derive important scaling laws to understand the mechanical behavior of Biological Cells under different processes such as Motility, Differentiation and Mitosis.

Mike Ciavarella's picture

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.

carpick's picture

Two Postdoc Positions: DFT/MD and AFM of Oxide Interfaces

The School of Engineering and Applied Science at the University of Pennsylvania invites applications for two full-time Postdoctoral Researcher positions in the laboratories of Prof. D.S. Srolovitz (https://www.seas.upenn.edu/directory/profile.php?ID=180) and Prof. Robert W. Carpick (http://carpick.seas.upenn.edu).

 

Mike Ciavarella's picture

A comment on "A dimensionless measure for adhesion and effects of the range of adhesion in contacts of nominally flat surfaces" by M. H. Muser

I attach a Letter I sent to the Editor of a tribology journal, concerning adhesion of rough surfaces. 

I contend that some "criteria" that have been proposed based on extrapolation of numerical results are due to the limitations in present numerical sophisticated rough contact simulations, which only span at most 3 orders of magnitude of wavelengths, so typically people simulate from nanometer to micrometer scale.

Mike Ciavarella's picture

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

Zhaohe Dai's picture

Interface-Governed Deformation of Nanobubbles and Nanotents Formed by Two-Dimensional Materials

In this paper, we experimentally characterize a simple and unified power law for the profiles of a variety of nanobubbles and nanotents formed by 2D materials such as graphene and MoS2 layers. https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.121.266101

Key image

ABSTRACT

hyunwoo's picture

Multifunctional “Hydrogel Skins” on Diverse Polymers with Arbitrary Shapes

In this paper, we introduce a new simple yet effective strategy to form "hydrogel skins" on polymer-based medical devices with arbitrary shapes. Hydrogel skins can convert any surface of polymer devices into robust, wet, soft, slippery, antifouling, and ionically conductive without affecting the original properties and geometries.

Abstract

Mike Ciavarella's picture

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? 

Mike Ciavarella's picture

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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