Buckling patterns in biaxially pre-stretched bilayer shells: wrinkles, creases, folds and fracture-like ridges. Issue 43 (18th October 2017)

• Record Type: Journal Article
• Authors: Al-Rashed, Rashed; López Jiménez, Francisco; Marthelot, Joel; Reis, Pedro M.
• Is Part Of: Soft matter. Volume 13:Issue 43(2017)
• Page Start: 7969
• Page End: 7978
• Publication Date: 2017-10-18
• Subjects: Soft condensed matter -- Periodicals; 530.413
• DOI: 10.1039/c7sm01828b
• Languages: English
• ISSNs: 1744-683X

Abstract

Abstract : We introduce a new experimental system to study the effects of pre-stretch on the buckling patterns that emerge from the biaxial compression of elastomeric bilayer shells. Abstract : We introduce a new experimental system to study the effects of pre-stretch on the buckling patterns that emerge from the biaxial compression of elastomeric bilayer shells. Upon fabrication of the samples, releasing the pre-stretch in the substrate through deflation places the outer film in a state of biaxial compression and yields a variety of buckling patterns. We systematically explore the parameter space by varying the pre-stretch of the substrate and the ratio between the stiffness of the substrate and film. The phase diagram of the system exhibits a variety of buckling patterns: from the classic periodic wrinkle to creases, folds, and high aspect ratio ridges. Our system is capable of readily transitioning between these buckling patterns, a first for biaxial systems. We focus on the wrinkle to ridge transition. In the latter, we find that pre-stretch plays an essential role and that the ridge geometry (width, height) remains nearly constant throughout their formation process. For the localized ridged patterns, we find that the propagation of the ridge tip depends strongly on both strain and stiffness ratio, in a way that is akin to hierarchical fracture.