Origami-inspired thin-film shape memory alloy devices

Abstract

We describe the design and fabrication of miniaturized origami structures based on thin-film shape memory alloys. These devices are attractive for medical implants, as they overcome the opposing requirements of crimping the implant for insertion into an artery while keeping sensitive parts of the implant nearly stress-free. The designs are based on a group theory approach in which compatibility at a few creases implies the foldability of the whole structure. Importantly, this approach is versatile and thus provides a pathway for patient-specific treatment of brain aneurysms of differing shapes and sizes. The wafer-based monolithic fabrication method demonstrated here, which comprises thin-film deposition, lithography, and etching using sacrificial layers, is a prerequisite for any integrated self-folding mechanism or sensors and will revolutionize the availability of miniaturized implants, allowing for new and safer medical treatments.

4D Multiscale Origami Soft Robots: A Review

“…Shape-memory materials are smart materials that can return to their original shape when triggered by an external stimulus, such as a temperature change. Shape-memory polymers (SMPs) [ 41 , 42 , 43 , 44 ] and shape-memory alloys (SMAs) [ 42 , 43 , 44 , 45 , 46 ] have been widely used in robotics. The shape-memory property of these materials makes them applicable in numerous fields including biomedical devices, aerospace structures, and morphing structures.…”

Modeling planar kirigami metamaterials as generalized elastic continua

“…Let (y eff , ξ) be a local minimizer to the potential energy in Eq. (7). Then, by taking the first variation of the energy functional,…”

“…The geometric rules linking design to deformation in such systems have captivated theorists [3][4][5]. In parallel, the embrace of shapemorphing in modern engineering -for the design of stents [6,7], soft robotic grippers [8,9], deployable space structures [10,11], and the like -has drawn applied researchers to these systems in an effort to demonstrate new functionalities. Thus, mechanical metamaterials sit at the intersection of engineering design and mechanics, where new paradigms are needed to realize their full potential.…”

Artificial intelligence automates the characterization of reversibly actuating planar-flow-casted NiTi shape memory alloy foil

“…A system capable of predicting the potential achievable actuation angles and the amount of force that in the past can be only generated by many experiments on the SMA foil, could make the SMA material characterization significantly faster, hence also making the material design more efficient and optimised. We aimed to design an automated and rapid SMA characterization system to achieve two primary objectives [27][28][29][30][31][32][33]. Firstly, we established a capability (aim A) to predict possible actuation angles achievable by a freshly manufactured foil, purely based on the dynamic maximum body temperature of the foil while under the thermal excitement.…”