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research

Computing wrinkling and restabilization of stretched sheets based on a consistent finite-strain plate theory

Submitted by Fan Xu on

It was reported both in experiments and computations using some classical plate theories that wrinkles can appear in a uniaxially stretched rectangular hyperelastic film with clamped-clamped boundaries and can be suppressed upon further tension. Here, based on a recently-available consistent finite-strain plate theory, we investigate this complex instability problem with isola-center bifurcation (the nontrivial solution curve begins and ends at two distinct points on the trivial line) in more depth and present an efficient numerical algorithm.

Effects of Cleavage Plane and Material Strength on Fracture of Polycrystalline Brittle Materials: A Phase-Field Modeling Study

Submitted by mohsenzaeem on

A modified phase-field model for fracture is presented which includes the material strength and cleavage planes to quantitatively predict the crack propagation path and the mechanical response in polycrystalline brittle materials. Computational Materials Science 197 (2021) 110642 (11 pages).

Mathematically exploring wrinkle evolution

Submitted by Fan Xu on

Wrinkling is one of the most important mechanical deformation modes (for example, buckling and crumpling) that are omnipresent in our daily life: for instance, wrinkled fingers after soaking in water for a prolonged time, the folds within the brain, and metal wrinkles after a car collision, to name a few.

EML Webinar (Season 2) by Ju Li, on 16 June 2021: Elastic Strain Engineering for Unprecedented Properties

Submitted by Teng Li on

EML Webinar (Season 2) on 16 June 2021 will be given by Ju Li, MIT. Elastic Strain Engineering for Unprecedented Properties. Discussion Leaders: Sulin Zhang, The Pennsylvania State University

Time: 10 am Boston, 3 pm London, 10 pm Beijing on 16 June 2021

Zoom Link: https://ter.ps/EMLWebinarS2

Programmable 3D Self-Folding Structures with Strain Engineering

Submitted by zichen on

Self-assembly of three-dimensional (3D) structures, through bending, twisting, folding, and buckling, has garnered broad interest among physicists, mathematicians, chemists, and biologists. Herein strain engineering and geometric frustration as an on-demand strategy for fabricating spontaneous rolling “origami” structures with programmable multistability across multiple length scales are exploited.

Smart Laser-Writable Micropatterns with Multiscale Photo/ Moisture Reconstructible Structure

Submitted by zichen on

The design of a dynamic, versatile, convertible, and responsive micropatterned system is realized by a photo/moisture reconstructible multiscale film-substrate bilayer structure. Specifically, a hydrophilic polyvinyl alcohol (PVA)/laponite (LP) thin film is covalently bonded to a photothermally active polydimethylsiloxane (PDMS)/carbon black (CB) soft substrate. A laser engraver can inscribe programmable aligned micro-wrinkles by manipulating laser power and spatiotemporal control.

Critical thresholds for mode-coupling instability in viscoelastic sliding contacts

Submitted by Antonio Papangelo on

Mode-coupling instabilities are known to trigger self-excited vibrations in sliding contacts. Here, the conditions for mode-coupling (or "flutter") instability in the contact between a spherical oscillator and a moving viscoelastic substrate are studied. The work extends the classical 2-Degrees-Of-Freedom conveyor belt model and accounts for viscoelastic dissipation in the substrate, adhesive friction at the interface and non-linear normal contact stiffness as derived from numerical simulations based on a boundary element method capable of accounting for linear viscoelastic effects.