An Inverse Design Method of Buckling-Guided Assembly for Ribbon-Type 3D Structures

Abstract

Mechanically guided three-dimensional (3D) assembly based on the controlled buckling of pre-designed 2D thin-film precursors provides deterministic routes to complex 3D mesostructures in diverse functional materials, with access to a broad range of material types and length scales. Existing mechanics studies on this topic mainly focus on the forward problem that aims at predicting the configurations of assembled 3D structures, especially ribbon-shaped structures, given the configuration of initial 2D precursor and loading magnitude. The inverse design problem that maps the target 3D structure onto an unknown 2D precursor in the context of a prescribed loading method is essential for practical applications, but remains a challenge. This paper proposes a systematic optimization method to solve the inverse design of ribbon-type 3D geometries assembled through the buckling-guided approach. In addition to the torsional angle of the cross section, this method introduces the non-uniform width distribution of the initial ribbon structure and the loading mode as additional design variables, which can significantly enhance the optimization accuracy for reproducing the desired 3D centroid line of the target ribbon. Extension of this method allows the inverse design of entire 3D ribbon configurations with specific geometries, taking into account both the centroid line and the torsion for the cross section. Computational and experimental studies over a variety of elaborate examples, encompassing both the single-ribbon and ribbon-framework structures, demonstrate the effectiveness and applicability of the developed method.

Flexible and Stretchable Photonics: The Next Stretch of Opportunities

“…After releasing the prestretching of the substrate, the unbonded region pops up and forms a deterministic 3D topography due to the constrained buckling of the 2D precursor. These 3D architectures, which can be predicted by mechanical analysis, are precisely controlled by the geometries of 2D precursor and bonded sites. ,, Further improvements of this method include the inverse design of the precursor , and the reconfiguration of the 3D structure through the incorporation of shape-memory or transient materials. − To generate the stress needed for the assembly without transferring the device onto another substrate, it is possible to resort to differential stresses caused, for example, by heating, as illustrated by the folding process of Figure c. The Sn hinges reflow during etching, creating the torque that orients the Al 2 O 3 panels. ,− The versatility and tunability of these 3D fabrication methods highlight the potential of their application to 3D integrated photonics.…”

“…These 3D architectures, which can be predicted by mechanical analysis, are precisely controlled by the geometries of 2D precursor and bonded sites. 13,215,224 Further improvements of this method include the inverse design of the precursor 225,226 and the reconfiguration of the 3D structure through the incorporation of shape-memory or transient materials. 227−229 To generate the stress needed for the assembly without transferring the device onto another substrate, it is possible to resort to differential stresses caused, for example, by heating, as illustrated by the folding process of Figure 8c.…”

A Nonlinear Mechanics Model of Zigzag Cellular Substrates for Stretchable Electronics

“…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].…”