Buckling

elastic

Delamination of thin films from an elastic substrate

The wrinkling and delamination of stiff thin films adhered to a polymer substrate  have important applications in `flexible electronics’. The resulting periodic structures, when used for circuitry, have remarkable mechanical properties since stretching or twisting of the substrate is mostly accommodated through  bending of the film, which minimizes fatigue or fracture.

ooisson

Negative Poisson’s ratio materials

We have uncovered negative Poisson’s ratio (auxetic) behavior in cellular solids that comprise a solid matrix with a square array of circular voids. The simplicity of the fabrication implies robust behavior, which is relevant over a range of scales.

CoiledTubing

Buckling of a rod inside a cylindrical constraint: Applications to coiled tubing operations

We present results of an experimental investigation of a new mechanism for extending the reach of an elastic rod injected into a horizontal cylindrical constraint, prior to the onset of helical buckling. This is accomplished through distributed, vertical vibration of the constraint during injection.

Coiling_PNAS

Coiling ‘spaghetti’ onto rigid substrates

The deployment of a rodlike structure onto a moving substrate is commonly found in a variety engineering applications, from the fabrication of nanotube serpentines to the laying of submarine cables and pipelines.

norbert_wrinkling

Wrinkling on curved surfaces & Smorphs: Smart Morphable Surface for Aerodynamic Drag Reduction

We have devised a new class of Smart Morphable Surfaces, which we refer to as Smorphs, that make use of a wrinkling instability on curved surfaces to generate custom, switchable and tunable topography.

Print

The Mechanics of Curly Hair

We tackle the deceivingly simple problem of a suspended naturally curved rod, which we consider as an analogue for curly hair, to predict its resulting shapes. The role of natural curvature in the mechanics of rods, as a control parameter, has been largely overlooked in the literature.

espaguetti

Geometrically nonlinear configurations of thin elastic rods

We have developed a novel continuation method to calculate the equilibria of elastic rods under large geometrically nonlinear displacements and rotations. To describe the kinematics we exploit the synthetic power and computational efficiency of quaternions.

experimento5

The Buckliball and Buckligami: buckling-induced encapsulation and soft Actuation

We introduce a class of continuum shell structures, the Buckliball, which undergoes folding induced by buckling under pressure loading.  The geometry of the Buckliball consists of a spherical shell patterned with a regular array of circular voids.

cortina

Wrinklons as Building-blocks in Wrinkling Cascades: From Curtains to Graphene Sheets

We show that thin sheets under boundary confinement spontaneously generate a universal self-similar hierarchy of wrinkles. From simple geometry arguments and energy scalings, we develop a formalism based on wrinklons (the  transition zones in the merging of two wrinkles) as building-blocks of the global pattern.