Controllable Propagation of Bending Waves in Wrinkled Films

Abstract

Wrinkling is a common phenomenon in natural and engineering film structures. The wrinkles influence the geometry and dynamic response of these structures. In this work, we investigate the wrinkling of a stretched thin film containing engineered microstructures and its derived functionality on controlling the propagation of bending waves. The underlying mechanism is revealed and the effect of wrinkles on the bandgap of bending waves is systematically evaluated via numerical simulations based on the Bloch wave theory. We show that wrinkles with a customized wavelength can be triggered in the microstructured film due to the mismatched deformation in the film. The bandgap of the wrinkled film can be finely tuned via applied stretching, resulting in the controllable propagation of bending waves in thin films. Our work provides fundamental insights into wave propagation in wrinkled films and potential applications for dynamic control of the wave propagation in engineering film structures.

Magneto‐Mechanical Metamaterials with Widely Tunable Mechanical Properties and Acoustic Bandgaps

“…Early designs use static and passive structures and have properties that cannot be changed after the metamaterials are fabricated (3,(14)(15)(16)(17). To address this issue, mechanical loads are used to change the metamaterial properties by altering the geometry through buckling or snapping (18)(19)(20). At the same time, the recent surge in the interests in smart structures that can dynamically change properties on demand has led to the emergence of active metamaterials (or stimuli-responsive metamaterials), which can transform into predetermined shapes when triggered by certain stimuli.…”

Confined thin film wrinkling on shape memory polymer with hybrid surface morphologies

“…They fabricated wrinkled metal films on polydimethylsiloxane (PDMS) substrates using mismatch of thermal expansion, which introduced compression strain in the film and led to the formation of wrinkling. Both experimental and theoretical studies have shown that stiff thin film-soft substrate bilayer system and compression strain beyond a critical value in the film are required to form thin film wrinkling [3,11,[15][16][17][18][19][20][21][22][23][24][25]. It is a process to balance the bending energy of the thin film and the strain energy of the substrate by adopting specific wrinkling wavelength and amplitude [17,23,26,27].…”