instability

We developed a method enabling a single material system to transform with untethered, reversible, low-powered reprogrammable deformations and shape locking via the application of magneto-thermomechanically triggered prestress on the Shape Memory Polymers (SMPs) and structural instability with asymmetric magnetic torque.

The transition between necking-mediated tensile failure of glasses, at elevated temperatures

and/or low strain-rates, and shear-banding-mediated tensile failure, at low temperatures and/or

high strain-rates, is investigated using tensile experiments on metallic glasses and atomistic simula-

tions. We experimentally and simulationally show that this transition occurs through a sequence of

macroscopic failure patterns, parametrized by the ultimate tensile strength. Quantitatively analyz-

Jie Ma, Daochen Yin, Zhi Sheng, Jian Cheng, Zheng Jia*, Teng Li, Shaoxing Qu, Delayed Tensile Instabilities of Hydrogels, Journal of the Mechanics and Physics of Solids, 168, 105052 (2022)

The Journal of Engineering Mechanics (JEM) launches a series of high-profile special issues. The first one is dedicated to “Instability and Failure of Nonclassical Materials and Nonlinear Structures”, guest edited by C.W. Lim (City University of Hong Kong), Stylianos Yiatros (Cyprus University of Technology), and Ahmer Wadee (Imperial College London). Submissions will be accepted until May 31, 2022.

For details, read the attached PDF.

We would like to invite you to participate in the Mini-Symposium on "Mechanics and Physics of Structures" within "ESMC2022 - 11th European Solid Mechanics Conference" in Galway (Ireland), July 4-8, 2022.

The deadline for abstract submission is November 19th, 2021.

Mini-symposium Organizers
Sebastien Neukirch (CNRS/UPMC),
Benoit Roman (CNRS/UPMC),
Keith Seffen (University of Cambridge),
Francesco Dal Corso (University of Trento)

We combine experiment and finite element simulation and come up with a design of a mechanical metamaterial which demonstrates snap-back induced hysteresis and energy dissipation. The resultant is an elastic system that can be used reversibly for many times. The underlying mechanism of existence of hysteresis and the physics of snap-back induced elastic instability is unveiled. Our results open an avenue for design and implementation of recoverable energy dissipation devices by harnessing mechanical instability.

 J. Li, V. Slesarenko, S. Rudykh Auxetic multiphase soft composite material design through instabilities with application for acoustic metamaterials. Soft Matter 14: 6171-6180 (2018) 

https://www.youtube.com/watch?v=RRlJhnIylNk

Reconfigurable electronic devices that can be shaped in two or more stable geometries modifying their functionalities have been realized, as highlighted by the Cover of March 2018 Issue of Nature Materials.

We would like to invite you to participate in the Mini-Symposium on "Mechanics and Physics of Solids and Structures" within "ESMC2018 - 10th European Solid Mechanics Conference" in Bologna (Italy), July 2-6, 2018.

The EXTENDED deadline for abstract submission is December 10, 2017.

Mini-symposium Organizers
Sebastien Neukirch (CNRS/UPMC),
Benoit Roman (CNRS/UPMC),
Keith Seffen (University of Cambridge),
Francesco Dal Corso (University of Trento)

Dear Colleagues,

We would like to invite you to submit an abstract to our symposium titled “362 Failure and Damage in Soft Materials: From Instabilies to Cracking” as part of the 18th U.S. National Congress for Theoretical and Applied Mechanics (Northwestern University in Chicago, IL, June 4-9, 2018).

We would like to invite you to participate in the Mini-Symposium on "Mechanics and Physics of Solids and Structures" within "ESMC2018 - 10th European Solid Mechanics Conference" in Bologna (Italy), July 2-6, 2018.

The deadline for abstract submission is November 15th, 2017.

Mini-symposium Organizers
Sebastien Neukirch (CNRS/UPMC),
Benoit Roman (CNRS/UPMC),
Keith Seffen (University of Cambridge),
Francesco Dal Corso (University of Trento)

V. Slesarenko and S. Rudykh, Microscopic and macroscopic instabilities in hyperelastic fiber composites.  J. Mech. Phys. Solids, 99, 471 – 482 (2017)

Abstract:

We present a systematic approach to deal with the modelling and analysis of the cracked rotating shafts behaviour. We begin by revisiting the problem of modelling the breathing mechanism of the crack. Here we consider an original approach based on the form we give to the energy of the system and then identify the mechanism parameters using 3D computations with unilateral contact conditions on the crack lips. A dimensionless flexibility is identified which makes the application of the approach to similar problems straightforward.

Because of the increasing need of energy, the plants installed by electricity supply utilities throughout the world are becoming larger and more highly stressed. Thus, the risk of turbogenerator shaft cracking is increasing also. The development and propagation of a crack represents the most common and trivial beginning of integrity losses in engineering structures.

Journal: PNAS, published ahead of print, March 9 2015, doi:10.1073/pnas.1418491112

Title: Endocytic proteins drive vesicle growth via instability in high membrane tension environment

Authors: Nikhil Walani, Jennifer Torres, and Ashutosh Agrawal 

Cavitation can be often observed in soft materials. Most previous studies were focused on cavitation in an elastomer, which is under different mechanical loadings. In this paper, we investigate cavitation in a constrained hydrogel induced by drying. With taking account of surface tension and chemo-mechanics of gels, we calculate the free energy of the system as a function of cavity size. The free energy landscape shows double-well structure, analogous to first-order phase transition.  Above the critical humidity, a cavity inside the gel is tiny.

Can buckling and instability of a structure be affected by Eshelby forces?  

We provide a positive answer to this question, see http://www.ing.unitn.it/~bigoni/blade.html