Post-wrinkle bifurcations in elastic bilayers with modest contrast in modulus

Abstract

Wrinkles, folds, creases and other elastic surface instabilities play a crucial role in many systems in nature and engineering. While surface instabilities of ideal bilayer structures with large contrasts in elastic stiffness are well understood, many natural and man-made structures are far from this ideal. To better understand the behavior of systems with modest stiffness contrast, in particular their secondary post-wrinkling bifurcations, we systematically vary the modulus contrast between the film and the substrate through a combination of experiments and finite element simulations. Above a modulus contrast of about 2, but below approximately 14, wrinkles represent the primary bifurcation mode, but can undergo two distinct types of secondary bifurcations upon further compression: (1) a direct transition from wrinkles to creases, and (2) wrinkles that first undergo period doubling, followed by a transition to creases.

Peristaltic Elastic Instability in an Inflated Cylindrical Channel

“…However, if sufficient compression is applied, the substrate itself becomes unstable to the formation of cusped surface furrows known as sulci or creases: the substrate becomes destabilizing rather than stabilizing. In this sense, peristalsis is a tensile analogue of the Biot instability, and the implied peristalsisballooning transition is likely to be a rich area for further study, just as the sulcus-wrinkle transition has been in compressive mechanics [65][66][67][68][69][70][71][72][73][74].…”

A flexible topo-optical sensing technology with ultra-high contrast

“…ε = 0.38). According to Kim and coworkers, surface wrinkles will first undergo period doubling, followed by the formation of creases under a modulus ratio (G f /G sub ) between 5.86 and 13.89 43,44 . A threshold strain (ε th ) is the compressive strain when the first fold occurs on surface, which is variable against the setting factors for multilayer.…”

Viscoelastic Characteristics of Mechanically Assembled Three-Dimensional Structures Formed by Compressive Buckling

“…Diverse manufacturing techniques based on phenomena such as mechanical buckling [25][26][27][28], self-folding induced by residual stress [29][30][31][32], surface instabilities [33][34][35], capillary forces [36][37][38], and temperature changes [39,40] can provide access to 3D micro-and nanostructures. Among these methods, the compressive buckling approach is notable for its ability to construct complex 3D structures with vibration behaviors (e.g., natural frequency) that can be tuned by applying tensile strain to the soft, elastomeric assembly platform.…”