Cellular Substrate to Facilitate Global Buckling of Serpentine Structures

Abstract

Three-dimensional (3D) serpentine mesostructures assembled by mechanics-guided, deterministic 3D assembly have potential applications in energy harvesting, mechanical sensing, and soft robotics. One limitation is that the serpentine structures are required to have sufficient bending stiffness such that they can overcome the adhesion with the underlying substrate to fully buckle into the 3D shape (global buckling). This note introduces the use of cellular substrate in place of conventional homogeneous substrate to reduce the adhesion energy and therefore ease the above limitation. A theoretical model based on energetic analysis suggests that cellular substrates significantly enlarge the design space of global buckling. Numerical examples show that the enlarged design space enables 3D serpentine structures with reduced maximum strains and resonant frequencies, which offers more possibilities for their potential applications.

A Nonlinear Mechanics Model of Zigzag Cellular Substrates for Stretchable Electronics

“…Based on Eqs. ( 11), ( 14), ( 15), (16), and ( 17), the global coordinates of points B and C can be obtained. The global coordinates of point C before deformation are…”

“…Significant progress has been achieved in materials [1][2][3] and mechanics [4][5][6][7][8][9][10][11][12][13][14][15][16] in offering the capability for stretchable electronics to be deformed into complex shapes without failure in functionality or structure. A recent direction of devising mechanically "invisible" skin-mounted stretchable electronics [17][18][19], which are ultrasoft and hardly detectable by skin through tactile sensation, demands a new class of compliant elastomer substrates.…”

Thermal and Mechanical Analyses of Compliant Thermoelectric Coils for Flexible and Bio-Integrated Devices

“…Many recent works have reported methods for forming such 3D configurations including 3D printing [14][15][16], thin-film folding and winkling [17][18][19], and actuation of active materials [20][21][22]. A collection of recent works [23][24][25][26][27][28][29][30][31][32] exploit a new strategy, i.e., buckling-guided 3D assembly that forms the 3D mesostructures by the compressive buckling of 2D precursors selectively bonded onto prestretched elastomer substrates. This assembly technique is intrinsically compatible with the planar technologies for a wide range of classes of functional materials, including device-grade semiconductors, and has some attractive features such as parallel operation, high speed, and size scalability, ranging from nanometers to centimeters [33][34][35][36][37][38][39][40].…”