Deployable mechanical metamaterials with multistep programmable transformation

Abstract

Transformations in shape are critical to actuation in engineered metamaterials. Existing engineering metamaterials are typically limited to a small number of shape transformations that must be built-in during material synthesis. Here, inspired by the multistability and programmability of kirigami-based self-folding elements, a robust framework is introduced for the construction of sequentially programmable and reprogrammable mechanical metamaterials. The materials can be locked into multiple stable deployed configurations and then, using tunable bistability enabled by temperature-responsive constituent materials, return to their original reference configurations or undergo mode bifurcation. The framework provides a platform to design metamaterials with multiple deployable and reversible configurations in response to external stimuli.

Digital Mechanical Metasurfaces for Reprogrammable Structural Display

“…It should be noted that (1) the dimensions of the MMP surface array adopted in the present study (i.e., 3 mm × 3 mm) were not large enough to be directly applied as braille printing for human finger interaction and (2) a systematic and quantitative study of the cyclic compression performances of the MMP surfaces is required before the braille display application becomes practical. Nevertheless, such a concept of interactive metasurfaces based on structurally reconfigurable stimuli-responsive microstructures could be an emerging direction and explored further for potential applications in other fields such as optics, ,,, sensors, − information reading and writing, − micromanipulations, − etc.…”

“…Stimuli-responsive micro-/nanostructured surfaces that are able to execute on-demand topographic changes upon external actuations have been increasingly studied due to their intriguing physical properties and potential applications for various surface engineering and micromanipulation devices. − Such devices include, for example, functional metasurfaces that exhibit anisotropic, reversible, and tunable biomimetic adhesive, − wetting, − optical, − acoustic, and/or mechanical properties, , ultrasensitive sensors and actuators that can sense and/or apply weak mechanical signals, − and miniature soft robots that can perform programmed transformations and locomotions, − among many others. − For the responsive structured surfaces, it is highly desirable to achieve not only programmable but also reprogrammable actuation performances such that the surface topography can be controlled to configure at a predesigned manner and then easily readapt into multiple new configurations as demanded. ,, Although significant advances have been made in designing and fabricating programmable structured surfaces, − ,,,− ,− ,− the actuated configurations and topography of existing surfaces are usually fixed once the fabrication is completed. There have been a few efforts in developing reprogrammable structured surfaces in the literature. − These efforts, however, are often limited to specif...…”

Auxeticity as a Mechanobiological Tool to Create Meta-Biomaterials

“…4D-printed medical devices have many applications ranging between cardiovascular engineering to orthopedic implants and beyond to create specific biological responses . One recent example of such applications involves the development of stimuli-responsive deployable metamaterials with dynamic Poisson’s ratios (Figure h). ,, Moreover, 4D-printed deployable implants can be implanted using minimally invasive surgical techniques. Upon external actuation or stimulation, such deployable meta-implants expand and fit into a cavity or defect zone. , It is, however, important to gain a better understanding of the interaction between 4D-(bio)­printed structures and living tissues.…”

Magnetic poles enabled kirigami meta-structure for stable mechanical memory storage with high information density and structural robustness

“…Mechanical meta-structure (or meta-material) have been demonstrated with various exotic properties beyond natural materials [1][2][3][4] . Pre-assigned with unique structural units, mechanical metamaterials can be integrated with mechanical intelligence (such as snap-through based instability 5,6 , bi/multi-stability [7][8][9] , topological (re)programmability [10][11][12] ) and/or materials intelligence 3,13,14 (for example combining with thermo-/electro-/magneto-actuated materials including liquid crystal elastomer 15,16 , shape memory alloy/polymer [17][18][19] , ferromagnetic material [20][21][22][23] , hydrogel 24,25 , dielectric materials 26 etc.) to achieve tunable and (re)programmable mechanical properties 27,28 , morph target shapes [29][30][31] , imitate electrical circuits 32,33 , perform logic computation 27 , encrypt/process simple information 34,35 , sense/intercept external environment conditions 36 , and/or act as multi-functional robotic structural platforms 37 .…”