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.
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.
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)
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).
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)
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.
I am writing to invite your contirbution to the mini-symposium on failure and instability in soft materials and geomaterials co-organized by myself, Joshua White, Pencheng Fu, Nikolaos Bouklas, Wei Wang and Christian Linder for the upcoming ICCM conference at Berkeley. More information can be found in the URL listed below.
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.
a quick question:- I am playing with continuum models of Contact (Hertz, Westergaard and so on) and friction laws. However, I prefer for my students to use ANSYS FEM code. In Ansys there is standard Coulomb, rate-dependence but not rate-state (unless one codes some user subroutines). See
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.
Hi, my question is on the use of Riks and other Arc length methods when analysing a system for gross plastic deformation. ASME B&PV code , in its investigation for Gross plastic deformation as a Load at which convergence does not take place. Now, as far as I understand, Newton Raphson method fails at locations of singularity in the stiffness matrix and also at Bifurcation points, it can trace the unstable primary paths. Both these issues can be overcome ( provided the limit point is not too sharp) by Riks and other Arc length methods.
in commercial FE codes, such as ABAQUS, ANSYS, there is option to get convergence in quasi-static analysis by using artificial damping factor. I tried to dig their documentation about this method, but it is somewhat sparse. Could some body recommend me some literature about this topic so that I can gain a better understanding about it.
This monograph gives a complete overview on the subject of nonconservative stability from the modern point of view. Relevant mathematical concepts are presented, as well as rigorous stability results and numerous classical and contemporary examples from mechanics and physics.
One postdoctoral research associate position is available (dates negotiable). The successful candidate will work on one or multiples of the following topics: mechanics of morphogenesis in plants and embryos, fast motion of plants (e.g., the Venus flytrap's rapid closure), mechanical self-assembly and instability of thin structures (e.g., DNA, plant tendrils, self-assembly of nanostructures, etc.), and bioinspired structures. The candidate should have received (or expect to receive very soon) a Ph.D.
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