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Abstract This is a roadmap article with multiple contributors on different aspects of embodying intelligence and computing in the mechanical domain of functional materials and structures. Overall, an IOP roadmap article is a broad, multi-author review with leaders in the field discussing the latest developments, commissioned by the editorial board. The intention here is to cover various topics of adaptive structural and material systems with mechano-intelligence in the overall roadmap, with twelve sections in total. These sections cover topics from materials to devices to systems, such as computational metamaterials, neuromorphic materials, mechanical and material logic, mechanical memory, soft matter computing, physical reservoir computing, wave-based computing, morphological computing, mechanical neural networks, plant-inspired intelligence, pneumatic logic circuits, intelligent robotics, and embodying mechano-intelligence for engineering functionalities via physical computing.  In this paper, we view all the 2-page sections with equal contributions to the overall roadmap article and thus list the authorship on the front page via alphabetical order of their last names.  On the other hand, for each individual section, the authors decide on their own the order of authorship.  

Abstract Emerging interest to synthesize active, engineered matter suggests a future where smart material systems and structures operate autonomously around people, serving diverse roles in engineering, medical, and scientific applications. Similar to biological organisms, a realization of active, engineered matter necessitates functionality culminating from a combination of sensory and control mechanisms in a versatile material frame. Recently, metamaterial platforms with integrated sensing and control have been exploited, so that outstanding non‐natural material behaviors are empowered by synergistic microstructures and controlled by smart materials and systems. This emerging body of science around active mechanical metamaterials offers a first glimpse at future foundations for autonomous engineered systems referred to here as soft, smart matter. Using natural inspirations, synergy across disciplines, and exploiting multiple length scales as well as multiple physics, researchers are devising compelling exemplars of actively controlled metamaterials, inspiring concepts for autonomous engineered matter. While scientific breakthroughs multiply in these fields, future technical challenges remain to be overcome to fulfill the vision of soft, smart matter. This Review surveys the intrinsically multidisciplinary body of science targeted to realize soft, smart matter via innovations in active mechanical metamaterials and proposes ongoing research targets that may deliver the promise of autonomous, engineered matter to full fruition. 

Spherically focused transducers have been long relied on to target acoustic energy delivery. Yet, these structures have limitations with respect to size and mobility for medical treatment applications. Recent developments in the field of reconfigurable structures reveal that the ancient art of origami inspires new platforms by which to enable spherical shapes that are additionally foldable for ease of transport. This research explores the opportunities for a unique, flat foldable doubly curved tessellated array to enable wave focusing capability similar to an ideal medical transducer shape: the spherical cap transducer. An analytical model of the doubly curved array is created and validated against data collected from a proof-of-concept array. The model is then leveraged to understand how the array design and complexity relatively govern the wave focusing capability. The findings show that doubly curved acoustic arrays do not require excessive facet refinement to achieve wave focusing similar to nominal spherically focused transducers. Yet, the optimal frequencies for which such capability is borne out vary substantially on the basis of array design. The discoveries of this research motivate future consideration of flat foldable doubly curved acoustic arrays for potential implementation into medical transducer development for hard-to-access surgical treatments. 

The development of materials with periodic microstructures provides the means to tune mechanical properties via prescribed collapse mechanisms. As investigations give attention to tunable unit cell designs, questions arise regarding strategic ways to exploit built‐up materials to empower large, programmable control over properties and material functionality. The potential to rationally design functionally graded elastomeric materials to yield prescribed mechanical properties is demonstrated herein. Following computational and experimental studies of simplified unit cells and layers, the results inspire ways to exploit linear elastic network analogies to design built‐up and functionally graded materials. This approach exemplifies a streamlined means to create pre‐programmed properties on the basis of simple calculations related to measurements from fundamental material constituents. The results build a foundation for innovative approaches to newly leverage elastomeric materials with programmable collapse for myriad engineering applications. 

In recent years, great advances in understanding the opportunities for nonlinear vibration energy harvesting systems have been achieved giving attention to either the structural or electrical subsystems. Yet, a notable disconnect appears in the knowledge on optimal means to integrate nonlinear energy harvesting structures with effective nonlinear rectifying and power management circuits for practical applications. Motivated to fill this knowledge gap, this research employs impedance principles to investigate power optimization strategies for a nonlinear vibration energy harvester interfaced with a bridge rectifier and a buck-boost converter. The frequency and amplitude dependence of the internal impedance of the harvester structure challenges the conventional impedance matching concepts. Instead, a system-level optimization strategy is established and validated through simulations and experiments. Through careful studies, the means to optimize the electrical power with partial information of the electrical load is revealed and verified in comparison to the full analysis. These results suggest that future study and implementation of optimal nonlinear energy harvesting systems may find effective guidance through power flow concepts built on linear theories despite the presence of nonlinearities in structures and circuits. 

Magnets have received broad attention for vibration energy harvesting due to noncontact, nonlinear forces that may be leveraged among harvesting system elements. Yet, opportunities to integrate multi-directional coupling among a nonlinear energy harvesting system subjected to impulsive excitations have not been scrutinized, despite widespread prevalence of such excitations. To characterize these potentials, this research investigates an energy harvesting system with magnetically induced nonlinearities and coupling effects under impulsive excitations. A system model is formulated and validated with experimental efforts to reconstruct static and dynamic properties of the system via simulations. Then, the model is harnessed to scrutinize dynamic response of the system when subjected to impulse conditions. This research reveals the clear impulse strength dependence and influence of asymmetries on total electrical energy capture and energy conversion efficiency that are tailored by magnetic force coupling. Asymmetry is found to promote greater impulse-to-electrical energy conversion when compared to the symmetric counterpart system and a benchmark nonlinear energy harvester. The roles of initial conditions exemplify how stored energy in an asymmetric energy harvesting system may be released during nonlinear impulsive response. These results provide insights about opportunities and challenges to incorporate magnetic coupling effects in nonlinear energy harvesting systems subjected to impulses.